5/6/2023 Page 1 of 99

Standard Paragraphs

API CRE Subcommittee on Mechanical Equipment

REVISION 25Sept 25, 2008

5/6/2023

5/6/2023 Page 2 of 99

SPECIAL NOTES

API publications necessarily address problems of a general nature. With respect to particular circumstances, local, state, and federal laws and regulations should be reviewed.

API is not undertaking to meet the duties of employers, manufacturers, or suppliers to warn and properly train and equip their employees, and others exposed, concerning health and safety risks and precautions, nor undertaking their obligations under local, state, or federal laws.

Information concerning safety and health risks and proper precautions with respect to particular materials and conditions should be obtained from the employer, the manufacturer or supplier of that material, or the material safety data sheet.

Nothing contained in any API publication is to be construed as granting any right, by implication or otherwise, for the manufacture, sale, or use of any method, apparatus, or product covered by letters patent. Neither should anything contained in the publication be construed as insuring anyone against liability for infringement of letters patent.

Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at least every five years. Sometimes a one-time extension of up to two years will be added to this review cycle. This publication will no longer be in effect five years after its publication date as an operative API standard or, where an extension has been granted, upon republication. Status of the publication can be ascertained from the API Downstream Segment [telephone (202) 682-8000]. A catalog of API publications and materials is published annually and updated quarterly by API, 1220 L Street, N.W., Washington, D.C. 20005.

This document was produced under API standardization procedures that ensure appropriate notification and participation in the developmental process and is designated as an API standard. Questions concerning the interpretation of the content of this standard or comments and questions concerning the procedures under which this standard was developed should be directed in writing to the general manager of the Downstream Segment, American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005. Requests for permission to reproduce or translate all or any part of the material published herein should also be addressed to the general manager.

API standards are published to facilitate the broad availability of proven, sound engineering and operating practices. These standards are not intended to obviate the need for applying sound engineering judgment regarding when and where these standards should be utilized. The formulation and publication of API standards is not intended in any way to inhibit anyone from using any other practices.

Any manufacturer marking equipment or materials in conformance with the marking requirements of an API standard is solely responsible for complying with all the applicable requirements of that standard. API does not represent, warrant, or guarantee that such products do in fact conform to the applicable API standard.

All rights reserved. No part of this work may be reproduced, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior

written permission from the publisher. Contact the Publisher,API Publishing Services, 1220 L Street, N.W., Washington, D.C. 20005.

Copyright © 1999 American Petroleum Institute

5/6/2023

5/6/2023 Page 3 of 99

FOREWORD

This standard is based on the accumulated knowledge and experience of manufacturers and users of ________. The objective of this standard is to provide a purchase specification to facilitate the procurement and manufacturer of _________ for use in petroleum, chemical, and gas industry services.

The primary purpose of this standard is to establish minimum requirements. This limitation in scope is one of charter as opposed to interest and concern.

Energy conservation is of concern and has become increasingly important in all aspects of equipment design, application, and operation. Thus innovative energy conserving approaches should be aggressively pursued by the manufacturer and the user during these steps. Alternative approaches that may result in improving energy utilization should be thoroughly investigated and brought forth. This is especially true of new equipment proposals, since the evaluation or purchase options will be based increasingly on total life costs as opposed to acquisition cost alone. Equipment manufacturers, in particular, are encouraged to suggest alternatives to those specified when such approaches achieve improved energy effectiveness and reduced total life costs without sacrifice of safety or reliability.

This standard requires the purchaser to specify certain details and features. Although it is recognized that the purchaser may desire to modify, delete, or amplify sections of this standard, it is strongly recommended that such modifications, deletions, and amplifications be made by supplementing this standard, rather than by rewriting or incorporating sections thereof into another standard.

API standards are published as an aid to procurement of standardized equipment and materials. These standards are not intended to inhibit purchasers or producers from purchasing or producing products made to other standards.

API publications may be used by anyone desiring to do so. Every effort has been made by the Institute to assure the accuracy and reliability of the data contained in them; however, the Institute makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal regulation with which this publication may conflict.

Suggested revisions are invited and should be submitted to the general manager of the Downstream Segment, American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005.

5/6/2023

5/6/2023 Page 4 of 99

IMPORTANT INFORMATION CONCERNING USE OF ASBESTOSOR ALTERNATIVE MATERIALS

Asbestos is specified or referenced for certain components of the equipment described in some API standards. It has been of extreme usefulness in minimizing fire hazards associated with petroleum processing. It has also been a universal sealing material, compatible with most refining fluid services.

Certain serious adverse health effects are associated with asbestos, among them the serious and often fatal diseases of lung cancer, asbestosis, and mesothelioma (a cancer of the chest and abdominal linings). The degree of exposure to asbestos varies with the product and the work practices involved.

Consult the most recent edition of the Occupational Safety and Health Administration (OSHA), U.S. Department of Labor, Occupational Safety and Health Standard for Asbestos, Tremolite, Anthophyllite, and Actinolite, 29 Code of Federal Regulations Section 1910.1001; the U.S. Environmental Protection Agency, National Emission Standard for Asbestos, 40 Code of Federal Regulations Sections 61.140 through 61.156; and the U.S. Environmental Protection Agency (EPA) rule on labeling requirements and phased banning of asbestos products (Sections 763.160-179).

There are currently in use and under development a number of substitute materials to replace asbestos in certain applications. Manufacturers and users are encouraged to develop and use effective substitute materials that can meet the specifications for, and operating requirements of, the equipment to which they would apply.

SAFETY AND HEALTH INFORMATION WITH RESPECT TO PARTICULAR PRODUCTS OR MATERIALS CAN BE OBTAINED FROM THE EMPLOYER, THE MANUFACTURER OR SUPPLIER OF THAT PRODUCT OR MATERIAL, OR THE MATERIAL SAFETY DATA SHEET.

5/6/2023

5/6/2023 Page 5 of 99

IntroductionUsers of this International Standard should be aware that further or differening requirements may be needed for individual applications. This International Standard is not intended to inhibit a vendor from offering, or the purchaser from accepting, alternative equipment or engineering solutions for the individual application. This may be particularly appropriate where there is innovative or developing technology. Where an alternative is offered, the vendor should identify any variations from this International Standard and provide details.

Discussion: The proposal section para 9.2.1 indicates description of alternative designs is required to be presented in the proposal.

Annex A specifies calculations for specific speed and suction specific speed.Annex B contains schematic drawings of cooling water and lubrication systems.Annex C specifies requirements for hydraulic power recovery turbines.Annex D specifies requirements for standard baseplates.Annex E contains an inspector's checklist.Annex F specifies criteria for piping design.Annex G give guidance on material class selection.Annex H specifies requirements and gives guidance on materials selection.Annex I specifies requirements for lateral analysis.Annex J specifies requirements for determining residual unbalance.Annex K contains seal chamber runout illustrations.Annex L contains forms which may be used to indicate vendor drawing and data requirements.Annex M contains forms which may be used to record test data.Annex N contains data sheets which purchasers are encouraged to use.

Discussion: ISO requires that the Annexes are numbered sequentially as they are referenced in the text. [ ISO Directives Part 2 - 4the edition 2001, paragraph 5.2.6]. Since the next paragraph references data sheets the data sheets would appear as Annex A if the above listing was not present. Thus by prelisting the Annexes before any of the other text, the annexes are placed in the desired order. The above is an excert from API 610. Each TF should determine the order in which they want the Annexes to appear.

This International Standard requires the purchaser to specify certain details and features.A bullet () at the beginning of a subclause or paragraph indicates that either a decision by, or further information from, the purchaser is required. Further information should be shown on the data sheets (see example in Annex XX) or stated in the quotation request and purchase order.[ISO Comment to 619]

In this International Standard, US Customary units are included in brackets for information.

Discussion: Bullets appear when the wording " if specified”, "the purchaser shall specify" or the purchaser “should”appears in the paragraph. A bullet is not required for "unless

5/6/2023

5/6/2023 Page 6 of 99

otherwise specified" or when a decision has been previously made and the phrase "When XXXXX has been specified" is used.

“When” specified has been replaced with “If specified” since “When” is a time and “if” is in the event that. Therefore “If” is proper, not “ when”.

Discussion: Information in square brackets i.e [ XXX ] are for Task Force use and reference only.

5/6/2023

5/6/2023 Page 7 of 99

CONTENTS

1 SCOPE................................................................................................................................. 1

2 NORMATIVE REFERENCES............................................................................................. 1

3 DEFINITION OF TERMS................................................................................................... 3

4 GENERAL......................................................................................................................... 134.1 Unit Responsibility.................................................................................................... 134.2 Unit Conversion......................................................................................................... 134.3 Nomenclature............................................................................................................. 13

5 REQUIREMENTS............................................................................................................. 135.1 Dimensions................................................................................................................ 135.2 Statutory Requirements.............................................................................................. 145.3 Alternative Designs.................................................................................................... 145.4 Conflicting Requirements........................................................................................... 14

6 BASIC DESIGN................................................................................................................. 146.1 General...................................................................................................................... 146.2 Pressure Casings (or Cylinders).................................................................................206.3 Casings (or Cylinder) Appurtenances.........................................................................246.4 Pressure Casings (or Cylinder) Connections...............................................................246.5 External Forces and Moments....................................................................................276.6 Rotating Elements (or Gear Elements).......................................................................276.7 Seals........................................................................................................................... 286.8 Dynamics................................................................................................................... 286.9 Bearings and Bearing Housings..................................................................................416.10 Lubrication................................................................................................................. 486.11 Materials.................................................................................................................... 566.12 Nameplates and Rotation Arrows...............................................................................68

7 ACCESSORIES................................................................................................................. 697.1 Drivers....................................................................................................................... 697.2 Couplings and Guards................................................................................................ 717.3 Belt Drives................................................................................................................. 737.4 Mounting Plates......................................................................................................... 747.5 Controls and Instrumentation.....................................................................................787.6 Piping........................................................................................................................ 887.7 Special Tools............................................................................................................. 947.8 Coatings, Insulation and Jacketing.............................................................................947.9 Starting Equipment.................................................................................................... 947.10 Fuel System............................................................................................................... 94

5/6/2023

5/6/2023 Page 8 of 99

8 INSPECTION, TESTING AND PREPARATION FOR SHIPMENT................................948.1 General...................................................................................................................... 948.2 Inspection................................................................................................................... 958.3 Testing....................................................................................................................... 988.4 Preparation for Shipment.........................................................................................105

9 VENDOR’S DATA.......................................................................................................... 1079.1 General.................................................................................................................... 1079.2 Proposals.................................................................................................................. 1089.3 Contract Data........................................................................................................... 110

Informative Annex1 Discussion on Flanges2 Discussion on Surface Finish3 Discussion on L10 Life of rolling element bearings4 Discussion on L10 Life for two and four bearing systems5 Manufacturers allowableDmN vis API allowable6 Manufacturers NDm used to determine API allowable7 Screw Threads

Figures3 Undamped Critical Speed Map...................................................................................30

Tables1 Driver Trip Speed...................................................................................................... 176.9-1 Bearing Selection....................................................................................................... 476.9-2 Anti-Friction Bearing Limiting ndm Factors………………………………………………...2 (Reference for placement of this table only)...............................................................833 Minimum Requirements for Piping Materials............................................................914 Maximum Severity of Defects in Castings.................................................................97E-2 International Materials Standards.............................................................................113

5/6/2023

5/6/2023 Page 9 of 99

Standard ParagraphsAPI CRE Subcommittee on Mechanical Equipment

Discussion:1. Titles of API SOME mechanical equipment specifications that reference “refinery service” should be changed to include “service in petroleum, chemical, and gas industry services.”

Discussion: New Work Items (NWI) submitted to ISO TC 67 should read “Petroleum, Petrochemical and Natural Gas Industries – (Equipment covered). The primary difference between the ISO and SOME title is that the API title includes “Chemical” instead of “Petrochemical” and “Gas Industry services” instead of “Natural Gas”. The API title has broader application since Gas Industries can also apply to the Air Separation industry and “Chemical” is broader than “Petrochemicals”.

ISO TC 67 titles are limited to the scope of that technical committee i.e petroleum and natural gas industries. TC’s other than TC67 are “equipment”focused and are not limited to a specific industry. Thus standards not in TC 67 such as pumps, compressors, seals have the option to include only the equipment and not the industry in the title. For example ( API 682) i.e.ISO 21049 title is “Pumps- shaft sealing systems for centrifugal and rotary pumps”.

ISO titled documents which have “Petrochemical” in their title will have to be adopted back using “chemical, and gas industries”. ISO titles for standards not in TC 67 which have only the equipment or the API “petroleum, chemical, and gas industries” can be adopted without a title change. It is therefore recommended that ISO standards not in TC 67 read like the API title or not reference the industry such as the above example for ISO 21049.

TF Chairs should include the appropriate proposed title when submitting a project justification to iniate work on an API document.

2. As the result of the request to provide insight into the standard paragraphs, a discussion paragraph has been added after some of the paragraphs. Discussion paragraphs are more informal than note paragraphs and are for the guidance of the TF and are not intended for inclusion and publication in the standards. NOTE paragraphs are part of the standard.

3. During review of this issue of the SPs it has been suggested these discussion paragraphsbe included in the base specifications. The SP task Force has decided to leave it up to each task force chair to determine the extent to which he chooses to incorporate any discussion paragraphs.

5/6/2023

5/6/2023 Page 10 of 99

1 Scope This standard covers the minimum requirements for [TF Chairmen: description or limitation

on the type insert the equipment the standard covers here] for use in the petroleum, chemical, and gas industry services. [The remainder of this paragraph generally gives further definition of equipment to which the standard is to be applied]

2 Normative ReferencesDiscussion: The referencing of standards in this document is presented in one of the following formats. The choice of the format depends upon the availability of similar documents:

In the following, US Ref yyyy is, for example, ASTM uuuu or API vvv.

a) Delete as many references as possible. This is normal guidance but there is still scope for some deletion in current drafts. (Refer to rewrite of SP 6.2.1 as an example with relation to the ASME code)

b) If the US reference can be replaced by the ISO reference, and all parties accept this, then use the ISO reference only. This is the desired ISO situation.

Example (from ISO 10423) “Viscosity and sand content shall be determined in accordance with ISO 10414-1.”

c) If the ISO and US references provide the same technical result for a particular provision, but it is desired to retain the traditional US reference, then write the provision in the form:" ....... in accordance with ISO xxxxx.NOTE - For the purposes of this provision, US Ref yyyy is equivalent to ISO xxxxx."

In this case US Ref yyyy is included as an informative reference in the bibliography.

Example “Steam turbine drivers shall be in accordance with ISO 10437NOTE - For the purposes of this provision API Std 612 is equivalent to ISO 10437."

This case will often include the case of an ISO standard based on an API where the ISO has not yet been adopted back by API. The note shall be placed in the line following each subclause/clause in which this formulation is used to state a provision. If this could be ambiguous, for example because the subclause/clause contains several such provisions, then the note shall be placed in the line following the sentence containing the provision.

SPTF GUIDANCE FOR API TF CHAIRS AND CONVENORS: This (c) approach should only be used if the ISO standard is IDENTICAL to the US or API standard. The “same

5/6/2023

5/6/2023 Page 11 of 99

technical result” wording is subjective and subject to interpretation, therefore the majority, if not all, dual references should appear as outlined in item d) following.

d) If the ISO and US reference do not provide the same technical result for a particular provision, BUT both results are acceptable then write the provision in the form:" ....... in accordance with ISO xxxxx or US Ref zzzz".

In this case both the ISO xxx and US Ref zzzz are normative references (if the provision is a requirement), or informative references (if the provision is a recommendation or permission).

Example (from ISO 10439) “The compressor shall be performance tested in accordance with ISO 5389 or ASME PTC 10.”

In the above example, the manufacturer is free to choose which of the referenced standards to apply. If it is considered necessary for the purchaser to select one or other of the referenced standards, the provision should be constructed as follows: “The compressor shall be performance tested in accordance with ISO 5389 or ASME PTC 10, as specified.”The SP’s referencing of standards requires the purchaser to choose what reference specifications are to be used and takes the form of the previous sentenance . It is recommended that the specifications particular to a standard and not covered by the SP’s be referenced in this mannor.

e) If an ISO Standard is not available but other internationally recognized similar standards are available, the wording used is internationally recognized standard. Refer to 6.11.1.2, for example, materials shall be identified by reference to applicable internationally recognized standards, or 6.11.2.5 Nodular iron castings shall be produced in accordance with internationally recognized standards such as ASTM A396. Not covered by the above ISO a,b,c,d therefore this guidance is still applicable.

f). If there are no other internationally recognized standards, the reference is presented as is presently in R22. as in 6.6.1 “These areas shall be properly demagnetized to the levels specified in API Standard 670... Not covered by the above ISO a,b,c,d therefore this guidance is still applicable.

g) Even if there is a ISO document available but the TF feels it not appropriate, the ISO reference does not have to be included in the document. (Per TC 67 procedures xxxxx).

h) Only reference published standards; this differs somewhat from ISO which allows referencing a document if it is in the FDIS stage. Referencing a standard before it is published is in conflict with SP2.5 therefore, only published standards should be referenced.

i) When the ASME code has been referenced in the SP the reference took one of the following three option:

a. Design (stress levels, etc.) (Refer to SP 6.2.1 as an example)

5/6/2023

5/6/2023 Page 12 of 99

b. NDE, welder qualification, etc.(Refer to SP 6.11.4)c. Buy-outs, other pressure vessels (pulsation dampers, coolers, etc.)

In the first category, (a) pull the paragraph out of the applicable code reference and include in the clause without reference to the specific standard. This agrees with ISO a) above. Refer to the rewrite of SP 6.2.1

For the second category, (b) Default to the ASME code and with purchasers approval allow EN 287 and 288. (Refer to rewrite of SP 6.11.4)

For the third category, (c) use the term “shall be in accordance with Section VIII of ASME pressure vessel code or other purchaser specified pressure design code”. This will be a bulleted item and included on the datasheet. [API 614]

Discussion: This paragraph previously did not have a default. It was modified to provide a default . The default is the the ASME code which is generally specified anyway. (90-10 rule)

2.1 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 10241:1992 , International terminology standards-Preparation and layout

ISO Directives Part 2:2001, Rules for the structure and drafting of International Standards

ISO Directives Part 3:1997, Rules for the structure and drafting of International Standards

ISO 6708:1995, Pipework components – Definition and selection of DN (nominal size)

ISO 7268:1983, Pipe components – Definition of nominal pressure

ISO 3740:2000, Acoustics – Determination of sound power levels of noise sources-Guidelines for the use of basic standards

ISO 3744:1994, Acoustics – Determination of sound power levels of noise sources using sound pressure –Engineering method in an essentially free field over a reflecting plane

ISO 3746:1995, Determination of sound power levels of noise sources using sound pressure –Survey method using n enveloping measurement surface over a reflecting plane – Technical Corrigendum 1

ISO 10494:1993, Gas turbine sets-Measurement of emitted airborne noise-Engineering/survey method

ISO 261: 1998, ISO general purpose metric screw threads-General plan

5/6/2023

5/6/2023 Page 13 of 99

ISO 262: 1998, ISO general purpose metric screw threads-Selected sizes for screw,bolts and nuts

ISO 724: 1993, ISO general-purpose metric screw threads-Basic dimensions

ISO 965: 1998, 1-5, ISO general purpose metric screw threads-Tolerances

ISO 7- l:1994, Pipe threads where pressure-tight joints are made on the threads

ISO 7-2: 2000, Pipe threads where pressure-tight joints are made on the threads-Verification by means of limit gauges

ISO 7005-1:1992, Metallic flanges – Steel flanges

ISO 7005-2:1988, Metallic flanges – Cast iron flanges

ISO 582:1995, Rolliing bearings – Chamfer dimensions – Maximum values

ISO 8821:1989, Mechanical vibration- Balancing-Shaft and fitment key convention

ISO 3448:1992, Industrial liquid lubricants – ISO viscosity classification

ISO 8068:1987, Petrolium products and lubricants – Petroleum lubricating oils for turbines (categories ISO-L-TSA and ISO-L-TGA)-Specifications

ISO 281:1990, Rolling bearings-Dynamic load ratings and rating life. TF Chair note:(This is not the latest issue of this standard, however theSPTF has reviewed the later edition and elected to continue referencing the first edition)

ISO 355:1977, Rolling bearings-Metric tapered roller bearings-Boundary dimensions and series designations

ISO 15;1998, Rolling bearings-Radial bearings-Boundary dimensions, general plan

ISO 464:1995, Rolling bearings-Radial bearings with locating snap rings-Dimensions and tolerances

ISO 492:2002, Rolling bearings-Radial bearings-Tolerances

ISO 582:1995, Rolling bearings-Chamfer dimensions-Maximum values

ISO 5753:1991, Rolling bearings-Radial internal clearances

ISO 8443:1999, Rolliing bearings-Radial ball bearings with flanged outer ring-Flange dimensions

5/6/2023

5/6/2023 Page 14 of 99

ISO 12043:1995, Rolling bearings-Singel-row cylindrical roller bearings-Chamfer dimensions for loose rib and non-rib sides

ISO 12044:1995, Rolling bearings-Single-row angular contact ball bearings-Chamfer dimensions for oouter ring non-thrust side

ISO 286-Part 1:1988, ISO system of limits and fits-Basis of tolerance, deviations and fits

ISO 286-Part 2:1988, ISO system of limits and fits-Tables of standard tolerance grades and limit deviations for holes and shafts

ISO 3290:2001, Rolling bearings-Balls-Dimensions and tolerances

SPTF NOTE: The above lising of standards is complete for the ISO references upto and including SP 6.9. Need to add references for later paragraphs onces these later paragraphs have been reviewed. In addition, need to add US Customary references.

SPTF: Look into the rules for adding standards to this reference list. Our interpretation is that if its not referenced in the document, it can not be included in these lists. KIPA inserted a reference specification to this list (GP CPLGS) which was not referenced in the document.

Note to Task Force Chairmen: 1) All standards referenced in the SP’s have been referenced in a normative manor and will eventually be all listed in Clause 2.

2) Additional standards applicable for each standard should be referenced in a normative mannor and also included in Clause 2.

3) If the task force references standards in an informative mannor, these shall be listed in a Bibliography. Wording “such as” preceeding a specification, makes it an informative reference. For example, 6.11.1.15 only requires the bolting to be carbon steel and the ASTM grade is not listed since the wording “such as” precedes the material spec. TF ‘s should realize that informative reference DO NOT MANDATE ANYTHING. It is suggested that all references to the extent possible, be Normative.

4) Notes following a paragraph are informative therefore you can not specify a requirement in a note.

5) Only those standards referenced in the specifications are to be included in the listing of specifications in Section 2. [ISO Directives Part 2, 6.2.2]

2.2 For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

Discussion: Undated references may be made only to a complete document or a part thereof and only in the following cases:

5/6/2023

5/6/2023 Page 15 of 99

a) it is accepted that it will be possible to use all future changes of the referenced document for the purposes of the referring documentb) for informative references.

Undated references shall be understood to include all amendments to and revisions of the referenced document. [ISO Directives Part 2: 2001 , 6.6.7.5.2]

• 2.3 The hierarchy of documents shall be specified.NOTE - Typical documents are user, industry, ISO and API specifications, data sheets , meeting notes and supplemental agreements.

3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply. [ISO Directive Part 2: 2001 Para 6.3.1] Note to Task Force Chairmen: 1) The following list of definitions is not necessarily complete or applicable to all standards. They should be amended and/or supplemented as appropriate for each standard.

2) New definitions should follow the format of these SP’s. ISO 10241: 1992 and ISO Directive Part 2: 2001 Annex C cover the rules for definitions. The requirements in these ISO documents which are applicable to the standard paragraphs are outlined below for easy reference.

3) The information in square brackets [ ] is the ISO paragraph containing the requirement,

TERM (word or words) BEING DEFINED

The term to be defined should be bold and in lower case [ISO 10241:1992 paragraph 6.2.2]

If more than one preferred term is seleced, they shall each be printed in boldface on a separate line . [ISO 10241:1992 paragraph 6.2.2.] (Refer to the definition of Normally Open, Normally closed, SP 3.34, 3.35, 3.36 for an example of this formatting requirement)

If a given term designates more than one concept, each concept shall be treated in a separate entry. [ISO 10241:1992 paragraph 6.2.2.] (Refer to the definition of Normally Open, Normally closed, SP 3.34, 3.35, 3.36 for an example of this formatting requirement)

When a term is used to represent several concepts as indicated in the previous paragraph, the subject to which each concept belongs is indicated between angle brackets, before the definition. [ISO 10241:1992 paragraph 6.2.10 & ISO Directives Part 2 : 2001 Paragraph C 3.6] (Refer to the definition of Normally Open, Normally closed, SP 3.34, 3.35, 3.36 for an example of this formatting requirement)

If there is a synonym for the term being defined, each shall be placed on a new line after the initial term. [ISO Directives Part 2 : 2001 paragraph C 3.3] (Refer to the definition of supplier and vendor, SP 3.75 for an example of this formatting requirement)

DEFINITION

5/6/2023

5/6/2023 Page 16 of 99

Definitions shall consist of a single phrase describing the term being defined. [ISO 10241:1992 paragraph 6.2.11] (Refer to Axially split joint SP 3.3 for an example of this formatting requirement)

Definitons should not contain a requirement [ISO Directive Part 2:2001 Paragraph C.1.5.2]

There shall be no punctuation (period, semi-colon, etc) at the end of a definition. [ISO Directive Part 2: 2001 Paragraph C 3.2 & ISO 10241:1992 paragraph 6.2.11]

The definition shall not begin with an article unless there is a specific reason, [ISO 10241:1992 paragraph 5.2.5.d ]

Definition shall not begin with a capital letter (except for proper nouns and the like).[ ISO 10241:1992 paragraph 6.2.11]

The term being defined should not appear in the definition [ISO 10241:1992 paragraph 6.2.10]

If a definition has been taken verbatim from another normative document, a reference shall be added between square brackets after the definition ISO 10241:1992 paragraph 6.2.11] (Refer to PN SP 3.44 for an example of this formatting requirement)

If a definition has been adapted and modified from another document, an explanation shall be given in a note. [ISO 10241:1992 paragraph 6.2.11] (Refer to NPS SP 3.36 for an example of this formatting requirement)

References to related definition – On a separate line after the definition insert the term cf (Cross reference) and the term and paragraph number [ISO 10241:1992 paragraph 6.2.13.2] (Refer to 3.2 definiton of Anchor bolts as an example of this formatting requirement).

If a term is used to represent several consepts, the subject field to which each consept belongs shall be indicated between angle brackets, before the definition. [ISO directives Part 2 : 2001 Para C 3.6] (Refer to definition of “local” SP 3.17 for an example of this formatting requirement)

If a given term designates more than one concept, each consept shall be treated in a separate definition entry. [ISO Directives Part 2; 2001 C.3.2 ] (Refer to definition of Normally open SP 3.34, 3.35, 3.36 for an example of this formatting requirement)

If more than one term to be defined is selected, they shall each be printed in boldface on a separate line. [[ISO 10241:1992 paragraph 6.2.2. (Refer to definition of Normally open SP 3.34, 3.35, 3.36 for an example of this formatting requirement)

No units shall be used in the definition of a term [[ISO 10241:1992 paragraph 5.2.5.e] (Refer to definition of Long wave cut-off SP 3.52 for an example of this formatting requirement)

The definition shall have the same grammatical form as the term. Thus to define a verb phrase shall be used; to define a singular noun, the singular shall be used. [ISO 10241:1992 paragraph 5.2.5.a] (Refer to definition of Radially split joint SP 3.51for an example of this formatting requirement)

Parenthese and square brackets shall be used only if they constitute a normal written form of the term. They shall not be used to show alternative terms [ISO 10241:1992 paragraph 6.2.2]

5/6/2023

5/6/2023 Page 17 of 99

“must” vs “shall” - “Do not use “must” as an alternative for “shall”. [ISO Directives Part 3:1997 Annex E table E.1 and ISO Directives Part 2 Annex G ] (Refer to the SP 5.1 modifications of “Statutory Requirement” as an example of this ISO formatting requirement)

NOTES after the definition

Notes may be added to a definion after the definition. The term NOTE shall be capatilized followed by a dash. A note shall be on a separate line in smaller type and should have the following format:

NOTE – Insert here the note. [ISO 10241:1992 paragraph 6.2.15]( Refer to 3.10 gauge board as an example of this formatting requirement).

When several notes occur within the same clause, they shall be designated “NOTE 1”, “NOTE 2”, NOTE 3”, etc. and placed on separate lines.

Can’t state a requirement in a NOTE. NOTES are intended to give additional information to assist in the understanding or use of the document. [ISO Directives Part 2: 2001 paragraph 6.5.1] (Refer to SP XXX as an example of this formatting requirement).

“May & Can” The use of the word “may” is not appropriate for use in a NOTE since it implies “permission” to perform a requirement, and requirements are not allowed in a NOTE. The use of the word “can” is used to indicate a possibility and is therefore not a requirement and is appropriately used in a NOTE. [ISO Directives Part 2 Annex G paragraph G.3]. The use of the word “might” also indicates a possibility and is appropriately used in a NOTE [D.Sales comments on SP 6.1.7.1] . May implies “permitted” but not “required”. Have not “muddied the water” by introducing “Might”

When EXAMPLES and NOTES are provided after a definition, EXAMPLE comes first and the NOTE is placed below the EXAMPLE on a separate line.[ISO Directives Part 2: 2001 paragraph C.3.9] (Refer to NPS SP 3.36 as an example of this formatting requirement)

ABBREVIATIONS

Abbreviations – An abbreviation may be listed before or after the term the abbreviation refers to, depending on which is the preferred term. The abbreviation is on a separate line and in lower or upper case in accordance with the normal usage. Periods are used in accordance with normal usage. [ISO 10241:1992 paragraph 6.2.5] (Refer to 3.36 NPS as an example of this formatting requirement)

CROSS REFERENCING

When referring to another definition the cross referenced definition shall be inserted following the definition. The cross reference should be in boldface type preceded by the small letters “cf.” and followed by the cross referenced paragraph in parenthese. [ISO 10241:1992 paragraph 6.2.13.2] (Refer to Anchor bolt SP 3.2 as an example of this formatting requirement)

EXAMPLES OF TERM USAGE

An example of the defined term may be given in a separate paragraph . The term EXAMPLE shall be capitalized followed by a dash line. The example shall be on a separate line in smaller type and should have the following format:

5/6/2023

5/6/2023 Page 18 of 99

EXAMPLE – Insert here an example of the defined term. [ISO 10241:1992 paragraph 6.2.14] (Refer to 3.36 NPS as an example of this formatting requirement)

When EXAMPLES and NOTES are provided after a definition, EXAMPLE comes first and the NOTE.[ISO Directives Part 2: 2001 C.3.9] (Refer to NPS SP 3.36 as an example of this formatting requirement)

3.1alarm pointpreset value of a measured parameter at which an alarm is activated to warn of a condition that requires corrective action

Discussion: All alarm points have to be measured however all measured points do not have to be alarmed.

3.2alloy steelsteel with the maximum range given for the content of alloying elements which exceeds one or more of the following: manganese, 1.65%; silicon, 0.60%: copper, 0.60%; or in which a definite minimum quantity of any of the following alloys are specified or required within the limits of the recognized field of constructional alloy steels: aliminum, boron, chromium up to 3.99%, cobalt, columbium, molybdium, nickel, titanium, tungsten, vanadium, zirconium, or any other alloying element added to obtain a desired alloying effect [Metals Handbook???]

3.2anchor boltsbolts used to attach the equipment to the support structure (concrete foundation or steel structure)cf. hold-down bolt (3.12) [format per ISO 10241:1992 6.2.13.2][cf means cross reference]

3.3axially split jointjoint split with the principal face parallel to the shaft centerline [Formatted in accordance with ISO 10241 : 1992 5.2.5.a]

3.4BWGBirmingham wire gaugestandard series of sizes arbitrarily indicated by numbers, used in specifying and describing the thickness of sheet metal [format per ISO 10241: 1992 6.2.5]

Discussion: The term “wire gage” is used in describing the diameter of wire and the thickness of sheet metal. Within the SP it is used to describe the thickness of tubes in coolers. In the world of wire gages, the only consistency is that there is no consistency. There are many different standards for wire gauges, as in different countries, or for different kinds of metal,

5/6/2023

5/6/2023 Page 19 of 99

the Birmingham wire gauges and the American wire gauge being often used and designated by the abbreviations B. W. G. and A. W. G. respectively. Other wire gages are the Washburn & Moen, Imperial Standard (S.W.G), Stubs and the Brown & Sharpe.

There's a difference between gauge thicknesses of steel tubing and nonferrous tubes. The wall thickness of an 18 gauge aluminum bronze tube is 0 .0403 inch, and an 18 gauge steel tube, is 0 .049 inch.

Nonferrous alloys, copper base, and aluminum, use Brown & Sharp measurements, and steel uses Birmingham-Wire Gage (B.W.G.). However B.W.G. is used to describe the tube thickness of a copper/zinc/tin non-ferrous material such as UNS C44300 (ASTM B-111) (inhibited admiralty) in the SP’s. As a result, 18 gauge BWG measures 0 .049 inch. Brown & Sharp is 0 .0403 inch and the sheet steel manufacturing standard for 18 gauge is 0 .0478 inch. All of which differ from wire gauge dimensions.

Discussion: ISO 10241 paragraph 6.2.5 allows an abbreviation to be before or after the word to be defined depending on which on is the preferred term. It is more common to refer to B.W.G. than Birmingham wire gauge and therefore the definition in the SP will have B.W.G on the first line and Birmingham wire gauge on the second.

3.5commercial fastenerfastener manufactured to published consensus standards and stocked by manufacturers or distributors. [ASME B 18.12 :2001]

3.6critical speedshaft rotational speed at which the rotor-bearing-support system is in a state of resonance

3.7DNdiamétre nominalalphanumeric designation of size for components of a pipework system

EXAMPLE- DN20

NOTE 1- Adapted from ISO 6708:1995NOTE 2- The letters DN are followed by a dimensionless whole number which is indirectly related to the physical size, in millimeters, of the bore or outside diameter of the end connectionNOTE 3-The number following the letters DN does not represent a measurable valueNOTE 4- In those standards which use the DN designation system, any relationship between DN and component dimensions should be given, e.g. DN/OD or DN/ID. [ISO 6708:1995 (E)]

5/6/2023

5/6/2023 Page 20 of 99

 Discussion: The following table lists the corresponding  DN and NPS pipe sizes. TF chairmen should use this table in referencing these two systems of pipe size designations in their standards when including paragraphs not already covered by the SP's.    

Diameter Nominal- DN -(mm)

Nominal Pipe Size

- NPS -(inches)

6 1/88 ¼10 3/815 ½20 ¾25 132 1 ¼40 1 ½50 265 2 ½80 3100 4150 6200 8250 10300 12350 14400 16450 18500 20550 22600 24650 26700 28750 30800 32900 36

1 000 401 100 421 200 481 400 54

5/6/2023

5/6/2023 Page 21 of 99

1 500 601 600 641 800 722 000 802 200 88

 The following two paragraphs are from the discussion paragraphs after 3.36 NPS

1. Up to and including 12 in diameter piping, the bore is the nominal dimension of the pipe, above 12 in pipe, the OD is the nominal dimension of the pipe.2. The thickness of the pipe is determined by specifying the pipe schedule.

3.8designmanufacturer’s calculated parameter

NOTE- A term used by the equipment manufacturer to describe various parameters such as design power, design pressure, design temperature, or design speed. It is not intended for the purchaser to use this term. [Formated per ISO 10241: 1992, 6.2.11 & ISO Directive Part 2: 2001 C.1.5.2]

Discussion: The term design had been used loosely by the users to describe operating conditions such as the design point. It can also apply to the equipment. In an attempt to reduce confusion, the word DESIGN has been relegated to use by the manufacturer.

3.8fail safesystem or component which will cause the equipment to revert to a permanently safe condition (shutdown and/or depressurized) in the event of a component failure or failure of the energy supply to the system [API 614]

3.9 flammable fluid: (Refer to NFPA document number 30)Discussion : SPTF eliminated the definition for flammable since NFPA definition does not cover gases. In addition, the NFPA definition of flammable only covers liquids with flash points less than 100 F. We would have to add the definition of “combustable” since the NFPA definition of combustable covers liquids with flash points greater than 100 F. With out “Flammable” defined in the standard, one has to rely on the definition in Websters which states : “capable of being easily ignited and of burning quickly”. This definition covers liquids and gases.The information from NFPA 30 and a discussion on “Flammable” and “Combustable” is presented below:flammable fluid any liquid that has a closed-cup flash point at or below 37.8 ºC (100 º F) as determined by the test procedures and apparatus in paragraph 1.7.4 of NFPA 30:2003NOTE - Adapted from NFPA 30:2003 [Format per ISO 10241: 1992 paragraph 6.2.11]

5/6/2023

5/6/2023 Page 22 of 99

NFPA differentiates between flammable fluid and combustable fluid and also defines, liquid, flash point and what tests, depending on the fluids viscosity, to use to determine the closed-cup flash point.

Flammable fluids are easier to ignite than combustable fluids since the flash point of the flammable fluid is lower tha the combustable fluid.

Flash points are deterined experimentally by heating the liquid in a container and then introducing a small flame just above the liquid surface. The temperature at which there is a flash/ignition is recorded as the flash point.

Two general methods are called closed-cup and open-cup. The closed cup method prevents vapors from escaping and therefore usually results in a flash point that is a few degreed lower than in an open cup. Because the two methods give different results, one must always list the testing method when listing the flash point. Example: 100 o C (Closed cup)[MSDS Hyper Glosery http://www.ilpi.com/msds/ref/flashpoint.html]

A combustable liquid is one with the closed cup flash point ABOVE 37.8 ºC (100 º F) and further subdivides these fluids into 3 subcatagories. [NFPA 30:2003 paragraph 1.7.3.1]

Liquid is defined as any material that has a fluidity greater than that of 300 penetration asphalt when tested in accordance with ASTM D 5, Standard Method of Test for Penetration of Bituminous Materials. [NFPA 30:2003 paragraph 1.7.2.3]

Flash point is defined as the minimum temperature of a liquid at which sufficient vapor is given off to form an ignitable mixture with the air, near the surface of the the liquid or within the vessel used as determined by the appropriate test procedure and apparatus specified in paragraph 1.7.4 of NFPA 30:2003. [NFPA 30:2003 paragraph 1.7.2.2]

Determination of Flash Point is based on the viscosity of the liquid and are separated into two sub-categories. The flash points testing procedures referenced are ASTM D 56, ASTM D 93, ASTM D 3278, or ASTM D 3828. All these referenced procedures are closed cup procedures.

3.9gauge boardbracket or plate used to support and display gauges, switches and other instruments cf. panel (3.34) [format per ISO 10241 6.2.13.2][cf means cross reference]NOTE - A gauge board is not a panel. A gauge board is open and not enclosed. A panel is an enclosure.

3.10

general purpose application

application that is usually spared or is in non-critical service

5/6/2023

5/6/2023 Page 23 of 99

3.11heat rateenergy consumption of a prime mover per unit of output work

Discussion: Heat rate is a general term and other terms such as steam rate may be used on individual classes of equipment. For combustion engines or gas turbines, the heat rate is calculated on the basis of the lower heating value of the fuel.

API 616 “Gas Turbines” task force recommended these modifications based on the fact that the exact heating value of the fuel is unknown. It will be somewhere between the LHV and the HHV.

The steps in the design of the equipment are:a. Assume efficiencyb. Test the machinec. Now need to decide what the heating value of the input fuel is. The efficiency calculated depends on the value chosen. If the HHV is used a different efficiency will be calculated than if the LHV is used. The purpose of the definition is to specify which heating value is to be used. By not introducing any units i.e. BTU per KW or BTU per HP the definition is nondimensionalized.

3.12hold down bolts mounting boltsbolts holding the equipment to the mounting plate [format per ISO Directives Part 2: 2001, C 3.3]

Discussion: Hold down bolting is used to attach the equipment to the mounting plate. Anchor bolting is used to attach the mounting plate to the support structure (concrete foundation or steel structure). Refer to Paragraph 3.2 for definition of anchor bolts.

3.13hydrodynamic bearingsbearings that use the principles of hydrodynamic lubrication

Note - The bearing surfaces are oriented so that relative motion forms an oil wedge, or wedges, to support the load without shaft-to-bearing contact. [ISO made 2ed sentenance a note]

Discussion: SHAFT addresses thrust collars in addition to journals. WEDGES was added to describe the action of multiple dam bearings and thrust bearings.

3.14informativeinformation only cf. normative (3.35)

5/6/2023

5/6/2023 Page 24 of 99

NOTE - An informative reference or Annex provides advisory or explanatory information. It is intended to assist the understanding or use of the document

Discussion: Appendices which are required are titled NORMATIVE. Refer to 1.5.30 for the definition of normative. Appendices which are for information are to be titled informative.

Since notes are informative, requirements, instructions, or recommendations, are NOT TO BE INCLUDED in notes. Rule of thumb – You should be able to delete a note and not affect the documents requirements.

Refer to paragraph 2 for discussion on normative reference.

3.15inlet volume flowflow rate expressed in volume flow units at the conditions of pressure, temperature, compressibility and gas composition, including moisture content, at the compressor inlet flangeNOTE- Inlet volume flow is a specific example of Actual Volume Flow. Actual volume flow is the volume flow at any particular location such as interstage, impeller inlet, discharge or compressor discharge. Actual volume flow should not be used interchangeably therefore with inlet volume flow.

3.16local<position of devices> on or near the equipment or console [ ISO Directives Part 2 : 2001,Para C 3.6]

Discussion: The term “local” is used in multiple different contexts in the document (e.g. SP 6.1.11 “local codes”, SP 7.5.6.3 “local temperature”. ISO directives Part 2 :2001, Para C 3.6 states: “if a term is used to represent several consepts, the subject field to which each consept belongs shall be indicated between angle brackets, before the definition.

3.17maximum allowable speedhighest speed at which the manufacturer's design will permit continuous operationNOTE- The maximum allowable speed is usually set by rotor stress values.

Discussion: Revolutions per minute was removed from the definition since it is not necessary to apply units to revolutions.

Discussion: The maximum allowable speed and the maximum continuous speed differ in that the maximum continuous speed is with the specified fluid and the maximum allowable speed does not depend on the specified operating conditions.

The maximum allowable speed could be at a much higher speed than required for the specified fluid. For example, a compressor compressing a heavy molecular weight gas may be

5/6/2023

5/6/2023 Page 25 of 99

running at a much lower speed for aerodynamic reasons (high mach number) than dictated by impeller stresses.

3.18maximum allowable temperaturemaximum continuous temperature for which the manufacturer has designed the equipment (or any part to which the term is referred) when handling the specified fluid at the specified maximum operating pressure

Discussion: The maximum allowable temperature is usually set by material considerations. This may be the material of the casing or a temperature limit imposed by a gasket or O-ring.

The material strength i.e. yield point, or ultimate strength is temperature dependent. A components stress level can depend on operating pressure. Thus the margin between the strength limit of the material and the operating stresses depends on both the materials operating temperature and the components stress level. If the temperature is lowered, the materials strength increases and the stress level of the component may increase. This is the reason for associating the maximum allowable temperature to the maximum specified operating pressure.

3.19maximum allowable working pressuremaximum continuous pressure for which the manufacturer has designed the equipment (or any part to which the term is referred) when handling the specified fluid at the specified maximum operating temperature

Discussion: Refer to the discussion on maximum allowable temperature 3.18.

3.20maximum continuous speedhighest rotational speed (revolutions per minute) at which the machine, as built and tested, is capable of continuous operation with the specified fluid at any of the specified operating conditions. [API 671]

Discussion: The definition of maximum continuous speed was added since it did not exist previously.

The margin over design speed was moved to Section 2 since it is a specified requirement and not a definition.

All new machines are mechanically tested in the vendors shop. For rerated machines it may be in a full speed balance bunker or in the field.

3.21maximum discharge pressure (of a centrifugal pump or compressor)

5/6/2023

5/6/2023 Page 26 of 99

maximum suction pressure plus the maximum differential pressure the pump (or compressor) is able to develop, when operating with the furnished impeller(s) and the fluid with the maximum density [API 614]NOTE - Refer to 3.24 for the definition of maximum suction pressure..

Discussion: Operation above maximum continuous speed should be considered as a short term transient.

3.22maximum exhaust casing pressure (of a turbine)highest exhaust pressure that the purchaser requires the casing to contain, with motive fluid supplied at maximum inlet conditions..NOTE - The turbine casing will be subjected to the maximum temperature and pressure under these conditions.

Discussion: This is a maximum condition. Transients above this are not allowed.

This is not a performance criteria but a structural criteria. It depends on the application.

This term is traditionally used for steam turbines.

Although this term is defined in NEMA, it is good for other types of equipment besides steam turbines and may be modified by individual task forces to reflect the equipment their standards address. These terms also appear on the data sheets.

3.23maximum exhaust pressurehighest exhaust pressure at which the turbine is required to operate continuously

Discussion: The maximum exhaust pressure for steam turbines, is a requirement determined by site steam conditions, it is set by the purchaser.

Cooling in some Gas Turbine bearings depends on the turbines backpressure. In supplemental firing operation, high backpressures can be developed.

3.24maximum inlet pressure and temperaturehighest inlet pressure and temperature conditions at which the turbine is required to operate continuously

Discussion: This term is generally applicable to general and special purpose turbines.

3.25maximum sealing pressurehighest pressure the seals are required to seal during any specified static or operating condition and during start-up and shutdown

5/6/2023

5/6/2023 Page 27 of 99

Discussion: In determining this pressure, consideration should be given to the maximum suction pressure (refer to 3.24), buffer gas or flush fluid, and the effect of any internal clearance changes.

3.26maximum suction pressure (of a pump or compressor)highest suction pressure the pump or compressor will be subject to in service

Discussion: The maximum suction pressure may be determined by 1) Relief valve setting on the suction system 2) Maximum liquid level in a pump suction system 3) Maximum shutoff supply pressure from a suction booster pump 4) settling out pressure 5) leaking discharge check valve on parallel operating compressors or pumps.

3.27minimum allowable speedlowest speed (revolutions per minute) at which the manufacturer's design will permit continuous operation.

Discussion: Minimum allowable speed can be set by many factors. These may include but not limited to the following: location of critical speeds (lateral and torsional), blade natural frequencies, minimum differentials which need to be developed across close clearances for lubrication, cooling and rotor dynamic damping & stiffening, dry gas seal lift off, and minimum speed of shaft driven lubricating pumps..

3.28minimum allowable temperaturelowest temperature for which the manufacturer has designed the equipment (or any part to which the term is referred).

Discussion: The modifier CONTINUOUS has not been applied to this definition since brittle fracture can occur during a short time the component may be at the low temperature.

Minimum temperature can be caused by operating conditions including autorefrigeration, low ambients during shipping, installation, operation or shutdowns.

3.29minimum exhaust pressurelowest exhaust pressure at which the turbine is required to operate continuously

Discussion: Minimum exhaust pressure is one of the factors that can determine the maximum power a turbine can develop and may be specified by the purchaser, however, for a condensing turbine, it may be set by the turbine design considering such as velocity across the last stage blades when the condenser cooling water is cold.

3.30

5/6/2023

5/6/2023 Page 28 of 99

minimum inlet steam pressure and temperature (of a steam turbine)lowest inlet steam pressure and temperature conditions at which the turbine is required to operate continuously

Discussion: Minimum inlet steam pressure and temperature are used to determine the turbines performance. This data is supplied by the purchaser and API 611 and 612 require the turbine to develop the required power with the minimum inlet and maximum exhaust conditions.

3.31mounting platedevice used to attach equipment to concrete floundations; includes both baseplates and soleplates [API 687]

3.32normal operating pointpoint at which usual operation is expected and optimum efficiency is desired. This point is usually the point at which the vendor certifies that performance is within the tolerances stated in this standard

Discussion: This is the point which the purchaser usually economically evaluates the offerings. The vendor usually tries to select the machine such that it has its maximum efficiency at this point.

The certified performance is usually some measure of energy consumption. For Centrifugal compressors it is power, for Gas turbines it is heat rate, for steam turbines it is steam rate.

3.33normally opennormally closed [definition format per ISO Directives Part 2 C. 3.6]

<On-the-shelf> state of a device (e.g. automatically activated switch or actuated valve).

NOTE 1 - The following table gives examples of various devices and there on-the-shelf state.

DEVICE ON-THE-SHELF STATE

ELECTRICALLY ACTIVATED DEVICES

DEENERGIZED POSITION OF THE DEVICE.

AUTOMATICALLY ACTIVATED PRESSURE SWITCH

STATE OF THE CONTACTS AT AMBIENT PRESSURE

FLOW SWITCH STATE OF THE CONTACTS AT NO FLOW

LEVEL SWITCH STATE OF THE

5/6/2023

5/6/2023 Page 29 of 99

CONTACTS AT NO LEVELLIMIT SWITCH STATE OF THE

CONTACTS AT NON- ACTUATED CONDITION

SPEED SWITCH STATE OF THE CONTACTS AT 0 RPM

NOTE 2 - During operation of the equipment, these devices may be normally energized or actuated, therefore, the state of these devices during operation may not be the same as their on-the-shelf state.

Discussion : An example of the NOTE may be illustrated by a steam turbine trip solenoid in a fail safe system. For this case, the trip solenoid’s on-the-shelf state would be normally open. During operation, the solenoid is energized, holding it in the closed position. When a trip is initiated, the solenoid becomes deenergized (i.e. fail safe system), reverting to its on-the-shelf, open position, dumping the oil, shutting down the turbine. Thus during normal operation (e.g. energized) its state (closed) is not the same as its on-the-shelf state (open).

3.34normally opennormally closed <installed> deenergized or non activated state of a device (e.g. automatically activated switch or actuated valve).

NOTE 1- The installed state of these devices is the same as that described in Note 1 of 3.34

NOTE 2 - During operation of the equipment, these devices may be normally energized or actuated, therefore, the state of these devices during operation may not be the same as their on-the-shelf state.

NOTE 3 -The normal convention in wiring diagrams is to indicate the contact state in the on-the-shelf condition.

NOTE 4 - The normal convention in Process and Instrumentation Diagrams ( P&ID’S) is to identify the device in its normal operating condition and does not identify the state of the contacts.

3.35normally opennormally closed <manual hand valve> state during normal operation.

Discussion: The definition of a manual hand valve was added since manual hand valves are not covered in 3.34 & 3.35 and the position of a manual hand valve is whatever it is during normal operation. It has nothing to do with on-the-shelf condition.

3.36normative

5/6/2023

5/6/2023 Page 30 of 99

requiredcf. informative (3.15)

NOTE - A normative reference or Annex enumerates a requirement or mandate of the specification.

Discussion: This term is applied in the standard to certain Appendices. Although it has been stated many times in meetings that the information in the Appendices is not part of the standard nowhere in the standards is this stated. For this reason, the term normative is introduced.

3.37NPSnominal pipe sizedimensionless value approximately equal to the diameter in inches

EXAMPLE- NPS 3/4

NOTE 1- Adapted from ASME B 31.3-2002, para. 300.2.NOTE 2 - The letters NPS are followed by a dimensionless number which is related to the physical size, in inches of the bore or outside diameter of the pipe.

NOTE 3 -The number following the letters NPS does not represent a measurable value (Can’t specify in a note)

NOTE 4 - NPS is a designation of pipe size only. The pipe end may be threaded or prepared for a welded fitting.

Discussion;1. Up to and including 12 in diameter piping, the bore is the nominal dimension of the pipe, above 12 in pipe, the OD is the nominal dimension of the pipe.2. The thickness of the pipe is determined by specifying the pipe schedule.

3.38NPT American National Standard Pipe Taper thread form designation for pipe threads

EXAMPLE - ¾-14 NPT

NOTE- It is comprised of a number representing nominal pipe size followed by the number of threads per inch and the letters NPT representing the thread series.

Discussion: ANSI/ASME B.1.20.1 is the US standard for dimensions and gageing of general purpose pipe threads. There are 6 American standard pipe thread forms and corresponding designations as outlined below. Each has the general form of nominal pipe size followed by the number of threads per inch and a designation for the pipe thread series.

3/8 - 18 NPT

5/6/2023

5/6/2023 Page 31 of 99

1/8 - 27 NPSC ½ - 14 NPTR1/8 - 27 NPSM1/8 - 27 NPSL 1 - 11.5 NPSH

Each letter in the symbols has a definite significance as follows:

N= National (American) StandardP = PipeT = TaperC = CouplingS = StraightM = MechanicalL= LocknutH = Hose CouplingR= Ralling Fittings

Pipe size and number of threads per inch may be found in ASME B.1.20.1 Table 2 , a section of which has been reproduced for reference below. TF chairmen should use these designations when identifying pipe threads.

Refer to the discussion after 6.4.8 and 7.6.1.7 and for the discussion of ASME B 1.20.1 and US tapered pipe threads.

ASME B.1.20.1 Table 2

5/6/2023

5/6/2023 Page 32 of 99

3.39observedinspection or test where the purchaser is notified of the timing of the inspection or test and the inspection or test is performed as scheduled if the purchaser or his representative is not present

3.40oil mist reclassifierlong path orifice device which meters and controls the flow of oil mist to an application point

NOTE 1- The turbulent flow through the orifice causes the small mist particles from the header to agglomerate into larger size particles that more effectively wet the bearing surfaces.

NOTE 2 - Mist reclassifies are normally screwed into the face of the manifold block and stainless steel tubing channels the mist to the application point.

3.41

5/6/2023

5/6/2023 Page 33 of 99

oil mist directional reclassifieroil mist classifier that points the oil mist flow directly at the bearing

NOTE- Directional reclassifiers are mounted at the bearing and are used to overcome bearing windage and in those cases where mist flow through the bearing can not be otherwise assured

3.42oil mist lubricationlubrication systems that employ oil mist produced by atomization in a central unit and transported to the bearing housing, or housings, by compressed air

3.43ownerfinal recipient of the equipment who may delegate another agent as the purchaser of the equipment

3:44panelenclosure used to mount, display and protect gauges, switches and other instruments.

3.45PNnominal pressurenumerical designation relating to pressure that is a convenient round number for reference purposes. [ISO 7268:1983]

EXAMPLE - PN 100

NOTE - The permissible working pressure associated with a PN designation depends upon materials, design and working temperature and has to be selected from the pressure/temperature rating tables in corresponding standards. [ISO 7268-1983]

3.46PMIpositive material identification testingphysical evaluation or test of a material to confirm that the material is consistent with the selected or specified alloy material designated

NOTE - Adapted from API 578: 1999

3.47potential maximum power approximate maximum power to which a steam turbine can be uprated at the specified normal speed and steam conditions when it is furnished with larger or additional) nozzles and possibly with a larger governor-controlled valve or valves

5/6/2023

5/6/2023 Page 34 of 99

Discussion: This is a data sheet entry on the steam turbine standards. By comparing it against the quoted HP one can determine the additional turbine capability without major modifications to the turbine such as a new shaft or inlet casing.

3.48pressure casingcomposite of all stationary pressure containing parts of the unit, including all nozzles and other attached parts

Discussion: The pressure casing may be a single wall such as a pump casing or dual wall such as a reciprocating compressor cylinder or the jacketed dry screw compressor. In the case of dual wall casings, the inside wall is designed to contain the process pressure and the outside wall to contain the pressure caused by the cooling water. Pressure casing terminology usually does not apply to diaphragms, or bearing housings.

3.49 pure oil mist lubrication lubrication systems in which the mist both lubricates the bearing and purges the housing

NOTE-There is no oil level in the bearing housing when using pure oil mist lubrication. (i.e.dry sump)

[Formatted in accordance with ISO 10241:1992 6.2.2 which states that brackets shall not be used to show alternative terms]

Discussion: Every bearing does not have a classifier directing the oil mist directly on the bearing race. Therefore, to include the wording DIRECTLY lubricates would be misleading.

3.50purge oil mist lubrication lubrication systems in which the mist purges the bearing housing

NOTE - There is an oil level in the bearing housing when using purge oil mist lubrication and the bearing is lubricated by a conventional oil-bath, flinger or oil ring lubrication system. ( i.e.wet sump)

[Formatted in accordance with ISO 10241:1992 6.2.2 which states that brackets shall not be used to show alternative terms]

3.51

Discussion: The difference between the pure oil mist (3.44) and purge oil mist (3.45) is that the pure oil mist has a dry sump and the purge oil mist has oil in the sump. Purge oil mist purges a bearing which has a conventional oil flinger or oil ring lubrication system.

Purge oil mist systems generally are fitted with a constant level oiler type. The oiler can function as a sight glass indicator, ( to determine if too much or too little oil mist is being provided), and it can also assist in maintaining the oil level in the sump.

5/6/2023

5/6/2023 Page 35 of 99

3.52purchaseragency that issues the order and specification to the vendorNOTE - The purchaser may be the owner of the plant in which the equipment is to be installed or the owner's appointed agent.

Discussion: The definition of purchaser was added to compliment the definition of owner

3.52Ra arithmetric average of the absolute value of the profile height deviations recorded within the evaluation length and measured from the mean line

NOTE 1- Adapted from ASME B 46.1-2002 para 1.4.1.1

NOTE 2 - It is the average height of the entire surface, within the sampling length, from the mean line

Discussion: Refer to Informative Annex 2 for detailed disussion and tables explaining surface finish. These discussions and tables were too voluminous to include in the body of the Standard Paragraphs.

3.53 rolled thread thread produced by the action of a form tool that when pressed into the surface of a blank displaces material radially. [ASME B 18.12 Glossary of Terms for Mechanical Fasteners – 2001]

3.54roughness long-wavelength cutoffnominal rating of the electrical or digital filter that attenuates the long wavelengths of the surface profile to yield the roughness profile

NOTE 1- Roughness long-wavelength cutoff is usually expressed in millimeters.

NOTE 2 - In most electrical averaging instruments, the cutoff can be selected. It is a characteristic of the instrument rather than the surface being measured.

NOTE 3- Adapted from ASME B 46.1-2002, para. 1.3.5.

[Formatted in accordance with ISO 10241:1992 para. 5.2.5.e]

Discussion: Term is used in 6.1.20 and refer to Informative Annex 2 for detailed disussion and tables explaining surface finish. These discussions and tables were too voluminous to include in the body of the Standard Paragraphs.

5/6/2023

5/6/2023 Page 36 of 99

3.55radially split split with the principal joint perpendicular to the shaft centerline[Formatted in accordance with ISO 10241:1992 para. 5.2.5.a]

Discussion: Made similar to the definition of axially split

3.56rated pointmaximum specified capacity on the rated speed performance curve

Discussion: The term capacity is meant to refer to flow as well as power.

There is generally a difference between the normal operating point and the rated point since the normal operating point is where the equipment will usually operate and the rated point implies a maximum capacity point.

3.57rated speed100% speedhighest rotational speed (revolutions per minute) required to meet any of the specified operating conditions

Discussion: The rated speed is usually determined by either the maximum head operating point or the maximum capacity operating point. The rated speed is the speed on which the rated operating point lies. The rated speed may not be the normal operating speed since the normal operating speed is determined by the normal operating point.

For variable speed machines rated speed is not maximum continuous speed. Maximum continuous speed is 105% of the rated speed.

3.58relief valve set pressurepressure at which a relief valve starts to lift

Discussion: This definition is used in setting the maximum allowable working pressure (paragraph 3.17). That relief valve set pressure is the pressure at which the relief valve starts to lift and does not include accumulation. The margins built into the ASME code allowable stresses account for accumulation.

3.59remotelocation of a device when located away from the equipment or console, typically in a control room

5/6/2023

5/6/2023 Page 37 of 99

3.60rolling element bearing effective clearancebearings internal clearance under operating conditions

3.61 rolling element bearing initial clearancebearings internal clearance before it is installed on a shaft or in a housing

3.62rolling element bearing preloadcompressive force acting on a rolling element bearing when the bearing has zero internal clearance

3.63rolling element bearing sealring affixed to the bearings stationary race and contacting the rotating race

NOTE - Seals are used primarily to retain grease in the bearing.

3.64rolling element bearing shieldring affixed to the bearings stationary race and having a clearance between the shield and the rotating race

NOTE - Shields are used to control the flow of grease.

3.65shallrequired in order to conform to the specification

NOTE - Adapted from ISO/IEC Directives Part 2: 2001

3.665shouldrecommended but not required in order to conform to the specification

NOTE - Adapted from ISO/IEC Directives Part 2: 2001

Discussion: Please note the important difference between “shall” and “should”. If you use the word "should" for a paragraph then you must accept that the reader may, contractually, ignore the provision entirely. If this is not what you want, then use the word "shall" (if necessary, with conditions)."

3.67

5/6/2023

5/6/2023 Page 38 of 99

shutdown set pointpreset value of a measured parameter at which automatic or manual shutdown of the system or equipment is required

3.68soleplateplate attached to the foundation , with a mounting surface for equipment or for a baseplate [API 619]

3.69special purpose applicationapplication for which the equipment is designed for uninterrupted, continuous operation in critical service, and for which there is usually no installed spare equipment

Discussion: The user determines which services are critical.

3.70special tooltool which is not a commercially available catalog item

3.71standard volume flowflow rate expressed in volume flow units at standard conditions as follows:

ISO Standard Conditions

Flow: Cubic meters per hour (m3/h)Cubic meters per minute (m3/min)

Pressure: 1.013 bar

Temperature: 0 °C

U.S. Standard Conditions

Flow: Standard cubic feet per minute (scfm)Million standard cubic feet per day (mmscfd)

Pressure: 14.7 PSI

Temperature: 60 °F

3.72standbyservice state in which a piece of equipment is normally idle or idling and is capable of immediate automatic or manual start-up for continuous operation

5/6/2023

5/6/2023 Page 39 of 99

3.73stress intensityWhen the maximum shear stress theory is used to combine stresses, the stress intensity is equal to two times the maximum shear stress or the difference between the algebraically largest principal stress and the algebraically smallest principal stress at a given point

NOTE 1 - Tensile stresses are considered positive and compressive stresses are considered negative.

NOTE 2 – Adapted from ASME Boiler & Pressure Vessel Code Section VIII Div 2 Part AD-140(a)

Discussion: The code was revised to reduce the hydrotest pressure from 150% MAWP to 125% MAWP (in approximately 1990). The allowable stress levels of materials were increased to maintain the same hydrotest stress level at 125% MAWP hydrotest as previously occurred at 150% MAWP. This allowed pressure vessels to be designed to higher stress levels at MAWP.

3.74System 21thread inspection system typically utilizing fixed GO, NO-GO gages to assure interchangeable assembly of mating parts

NOTE - The threads passing this inspection fit between the maximum and minimum material limits. No dimensional data is recorded. GO and NO-GO gages only identify a product as it pertains to the maximum and minimum tolerance limits. Thread characteristics such as lead, flank angle, taper and roundness variations are confined within these limits with no specific control of their individual magnitudes. If the GO gage does not go, the thread exceeds the maximum material limit. i.e. one or more of the thread characteristics is too small for internal threads and too large for external threads. If the NO-GO gage goes, the thread is less than the minimum material limit. i.e. one or more of the thread characteristics is too large for internal threads and too small for external threads. A variable gage can also be configured to perform the GO, NO-GO inspection.

3.75System 22thread inspection system utilizing variable differential gages to assure interchangeable assembly of mating parts with dimensional cumulative and individual identification of critical component features or attributes

NOTE - The threads passing this inspection fit within the maximum and minimum material limits envelope. The cumulative variation of thread characteristics such as lead, flank angle, taper, and roundness is measured and confined within the maximum and minimum material envelop. Differential gaging uses two measurements. One gage is used to measure the functional diameter size, and another gage is used to measure the pitch diameter size.

3.76System 23 thread inspection system utilizing variable differential gages to assure interchangeable assembly of mating parts with dimensional identification and smaller acceptance tolerance of critical component features or attributes than System 22

5/6/2023

5/6/2023 Page 40 of 99

NOTE - The threads passing this inspection fit within the maximum and minimum material limits envelope. The magnitude of other thread characteristics such as lead, flank angle, taper, and roundness are further controlled within the maximum and minimum material limits. Thread characteristics (surface texture, etc.) for which no limiting requirements are specified do not require evaluation.

3.77TIRtotal indicator readingtotal indicated runoutdifference between the maximum and minimum readings of a dial indicator or similar device, monitoring a face or cylindrical surface during one complete revolution of the monitored surface

NOTE - For a cylindrical surface, the indicated runout implies an eccentricity equal to half the reading. For a flat face the indicated runout implies an out-of-squareness equal to the reading. If the diameter in question is not cylindrical or flat, the interpretation of the meaning of TIR is more complex and may represent ovality or surface irregularities.

3.78trip speed<electric motor driver> speed corresponding to the synchronous speed of the motor at maximum supply frequency at the motor terminals.[ ISO 10241 6.2.2]

Discussion :There is a definition of trip speed for an electric motor since Table 1 paragraph 6.9 uses the term Trip speed with relation to motors and paragraph 8.3.3.2.2 states: The speed shall be increased to trip speed and the equipment shall be run for a minimum of 15 minutes.

3.79trip speed<turbine, engine, expander, hydrostatic driver> speed at which the independent emergency overspeed device operates to shut down the driver [ ISO 10241 6.2.2]

3.80unit responsibilityobligation for coordinating the documentation, delivery and technical aspects of the equipment and all auxiliary systems included in the scope of the order

NOTE-The technical aspects to be considered include, but are not limited to, such factors as the power requirements, speed, rotation, general arrangement, couplings, dynamics, lubrication, sealing system, material test reports, instrumentation, piping, conformance to specifications and testing of components. [API 671]

5/6/2023

5/6/2023 Page 41 of 99

Discussion: If different components of the order are purchased separately by the purchaser, the responsibility for these components can subsequently be assigned to the vendor having unit responsibility.

3.81vendorsuppliermanufacturer or manufacturer’s agent that supplies the equipment

Note to TF Chairmen: Use vendor in the documents and not supplier

Discussion: The API mechanical equipment documents address the responsibilities between two parties. For the purposes of these standards these parties are defined as the purchaser (3.40) and the vendor or supplier (3.54). There are many parties that are involved in the purchase and manufacturer of the equipment. These parties are given different titles depending on there location in the chain of the order. They may be called buyer, contractor, manufacturer, and subvendor. In all instances however, one party is purchasing something from another party. For example, the party supplying a lube oil console may be the console vendor to the compressor manufacturer, the subvendor to the purchaser, and the purchaser to components within the console. All of these terms however can be reduced to the purchaser and vendor or supplier. It is for this reason that only these two terms are defined. Attempts to define these other terms would only add confusion.

3.82witnessedinspection or test where the purchaser is notified of the timing of the inspection or test and a hold is placed on the inspection or test until the purchaser or the purchasers representative is in attendance

4 General4.1 UNIT RESPONSIBILITY

The vendor who has unit responsibility shall assure that all subvendors comply with the requirements of this standard and all reference documents. [API 618]

Discussion: Typically, the vendor who has unit responsibility invokes the applicable standards to his subvendors and they in turn invoke the applicable standards to there subvendors etc. It is not intended here that the unit responsible vendor know all of the subvendors which are required to manufacture the equipment. It is sufficient for him to pass this requirement on to each of his subvendors with the stipulation that they in turn pass the requirements on to their subvendors.

4.2 UNIT CONVERSION

5/6/2023

5/6/2023 Page 42 of 99

Discussion: The factors in Chapter 15 of the API Manual of Petroleum Measurement Standards formally API 2564 were used to convert from U.S. Customary to SI units. The resulting exact SI units were then rounded off. It should be noted that paragraph 15.4.12 EXCEPTIONS states: “ The major exceptions to SI practice are as follows:”..Sub paragraph 5 Pressure—The bar (which equals 100 kilopascals - kPa) is an allowable unit.

4.3 NOMENCLATURE

A guide to XXXXX nomenclature can be found in Appendix E (Note to Task Force Chairmen: Fill in the name of the equipment standard being addressed.)

Discussion: This Appendix is tutorial in nature and helps standardize on the names of various components of the equipment.

5 Requirements 5.1 DIMENSIONS

The purchaser shall specify whether data, drawings, hardware (including fasteners) and equipment supplied to this standard shall use the SI or US customary system of measurements .NOTE - Dedicated Data Sheets for SI units and for US customary units are provided in Annex XXX.

Note to TF Chairman: Provide four boxes on each set of data sheets to allow the purchaser to specify if SI or US customary units are to be used for software (drawings, data, etc.) and fasteners.

5.2 STATUTORY REQUIREMENTS

The purchaser and the vendor shall mutually determine the measures to be taken to comply with any governmental codes, regulations, ordinances, directives,or rules that are applicable to the equipment its packaging and any preservatives used.,. [ISO directives Part 3:1997 Annex E]

Equipment installed in the European Economic Area (EEA) shall comply with all applicable European Union Directives.

NOTE - The European Economic Area includes the countries of the European Union plus Norway, Iceland and Liechtenstein.

Task Force Chairmen: Refer to Informative SP Annex 9 describing the ramifications of this statement.

5.4 DOCUMENTATION REQUIREMENTS

The hierarchy of documents shall be specified.

5/6/2023

5/6/2023 Page 43 of 99

NOTE - Typical documents include company and industry specifications, meeting notes, and modifications to these documents.

6 Basic Design6.1 GENERAL

6.1.1 The equipment (including auxiliaries) covered by this standard shall be designed and constructed for a minimum service life of 20 years and at least 5 years ( TF Chairmen: Use 3 years for GP Equipment) of uninterrupted operation [API 617] Shutting down the equipment to perform maintenance or inspection does not meet the continuous uninterrupted operation requirement.NOTE 1- It is recognized that these are design criteria.

NOTE 2 - It is realized that there are some services where this objective is easily attainable and others where it is difficult.

NOTE 3 - Auxiliary system design and design of the process in which the equipment is installed are very important in meeting this objective. [TI 6180203]

NOTE 4 - 9.2.1 requires the vendor to identify any component or maintenance requirement that would result in the need to shut down the equipment within the uninterrupted operational period.

Discussion: (From TI 6180203)

Question: Since this API clause calls for "an expected uninterrupted operation of at least 3 years", my question to you is, that whether such 3 years continuous operation is really possible or not, OR, this clause neglects the downtime required for the annual maintenance or in other words,

Does API 618 insist, that the compressor be designed for 3 YEARS MAINTENANCE FREE OPERATION ?

Reply: Yes, it is the intent of this standard to provide equipment (including auxiliaries) that have been designed to provide 3 years of uninterrupted operation, without annual maintenance. It is realized that there are some services where that objective is easily attainable and others where it is more difficult. The system design is a very important criterion in meeting this objective. Note that this is a design requirement. Manufacturers may choose to recommend reduced maintenance intervals dependant upon the proposed operating conditions.

6.1.2 The vendor shall assume unit responsibility for all equipment and all auxiliary systems included in the scope of the order.

Note to TF Chairmen: Suggest eliminating "unit" from standards covering such equipment as couplings, seals, and vibration monitoring, which are not usually designated as having unit responsibility.

5/6/2023

5/6/2023 Page 44 of 99

Discussion: This paragraph requires that each vendor who is a party to an order be responsible for the equipment he is supplying. Task forces responsible for equipment not generally designated as having unit responsibility (such as couplings, seals and L. O. systems) can delete "unit" from the paragraph. This will still make them responsible for the equipment they are supplying but not necessarily the entire train.

6.1.3 The purchaser shall specify the equipment's normal operating point.

6.1.4 Equipment driven by induction motors shall be rated at the actual motor speed for the rated load condition.

Discussion: Due to load, the motor runs at a slower speed than synchronous. This can be several percent depending on motor slip.

6.1.5 Control of the sound pressure level (SPL) of all equipment furnished shall be a joint effort of the purchaser and the vendor having unit responsibility. The equipment furnished by the vendor shall conform to the maximum allowable sound pressure level specified. In order to determine compliance, the vendor shall provide both maximum sound pressure and sound power level data per octive band for the equipment. ISO 3740 , ISO 3744 and ISO 3746 or ASME PTC 36 as specified, may be consulted for guidance. [610 uses the ISO references]

Discussion: Sound pressure levels are easier to determine than sound power levels. Therefore a screening sound pressure test is performed per ASME PTC 36 (For Gas turbines use ANSI B 133.8 and ISO 10494) (Refer to OPTIONAL TESTS in Section 4) In the event that the overall sound pressure levels do not meet those specified by the purchaser in this paragraph, diagnostic tests to determine the sound generated by each component in the train are to be run using the sound power level calculations in accordance with ISO XXX . The corrections can then be made to that component. If the initial easier performed sound pressure level test indicates the equipment meets the requirements of this paragraph there is no need to run the more demanding sound power level tests.

Discussion: Sound Power Vs Sound Pressure Level

The sound power level of a source can be treated as a property of that source under a given set of operating conditions. The sound pressure level however will vary depending on the environment in which the source is located as well as the distance from the source.

Vendors routinely take exception to guaranteeing a purchasers maximum allowable sound pressure level requirement due to the argument that the vendor has no control over the environment in which the equipment is to be located. The vendor has control, however, over the sound power level of the equipment.

6.1.6 Unless otherwise specified, cooling water system or systems shall be designed for the following conditions:

5/6/2023

5/6/2023 Page 45 of 99

Water Velocity over heat exchange surfaces ≥1,5 m/s to 2,5 m/s 5 ft/s to 8 ft/sMaximum allowable working pressure , MAWP, (Gauge) [614]

≥700 kPa (7 bar) ≥100 psig

Test pressure (≥1.5 MAWP) ≥1 050 kPa (10,5 bar) ≥150 psigMaximum pressure drop 100 kPa (1 bar) 15 psiMaximum inlet temperature 30 °C 90 °FMaximum outlet temperature 50 °C 120 °FMaximum temperature rise 20 K 30 °FMinimum temperature rise 10 K 20 °FWater side fouling factor 0,35 m2K/kW 0.002 hr-ft2-°F/BtuCorrosion allowance for carbon steel shells 3 mm 1/8 in

The vendor shall notify the purchaser if the criteria for minimum temperature rise and velocity over heat exchange surfaces result in a conflict. The criterion for velocity over heat exchange surfaces is intended to minimize water-side fouling; the criterion for minimum temperature rise is intended to minimize the use of cooling water. If such a conflict exists the purchaser shall approve the final selection.

NOTE - For water cooled bearing housings, maintaining the inlet water temperature above ambient air temp will prevent condensation of water in the bearing housing. ( Modified to eliminate “should” )

Discussion: The term "Unless otherwise specified" implies another alternative may be indicated by the purchaser. In most cases "Unless otherwise specified" has been introduced when a bullet has been eliminated.

Discussion: In SI units K is used for temperature rise without the (°) sign. C is shown with the (°) sign because C without the (°) sign means coulomb. API Manual of Petroleum Measurement Standards Chapter 15 page 17 indicates that temperature difference in the US Customary system of units is given in ºF. SPTF therefore elected to keep ºF as the unit for temperature difference and not use K.

Discussion: These cooling water design conditions have historically been representative of the conditions specified by the purchaser. They are supplied to result in consistent offerings in proposals. If a user has different conditions, they should be specified. [ Technical inquiry 610 01 03]

6.1.6.1 Provision shall be made for complete venting and draining of the system or systems.

6.1.7 Note to task force chairmen: Use either 6.1.7.1 (for centrifugal equipment) or 6.1.7.2 (for positive displacement equipment)

6.1.7.1 Equipment shall be designed to operate simultaneously at the maximum discharge pressure and trip speed without damage regardless of driver power. (ISO Recommendation)

5/6/2023

5/6/2023 Page 46 of 99

6.1.7.2 Equipment shall be designed to operate simultaneously at the relief valve setting and trip speed without damage regardless of driver power. (ISO Recommendation)

Discussion: Relief valves are not to be used to protect equipment against mechanical failure. They are used to protect equipment against overpressurization due to process upsets. The ability of the equipment to run to the relief valve setting or to the maximum allowable working pressure is covered in 6.1.8.

Reference to relief valves is eliminated for centrifugal equipment since the discharge piping and vessels for centrifugal pumps and compressors is generally designed for the maximum the equipment can develop in order to prevent relieving product to the flare. Relief valves are therefore generally not installed to protect centrifugal equipment. When positive displacement type equipment is installed, relief valves are generally provided and the equipment should be capable of operating to the relief valve setting.

6.1.8 The equipment's maximum continuous operating speed shall be not less than 105% of the rated speed for variable speed machines and shall be equal to the rated speed for constant speed motor drives.

Discussion: Unforeseen variations in operating conditions requires the equipment be capable of an additional 5% in speed.

The Maximum continuous and trip speeds for constant speed motors are the same speed. The operating speed is slightly less as caused by the slip frequency.

For equipment running in parallel, such as pumps, with a motor and turbine drive, the definition for the variable speed application shall govern for the motor driven pump. This will allow duplication of both pieces of driven equipment.

6.1.9 The equipment's trip speed shall not be less than the values in Table 1.

Note to TF Chairmen: Include as applicable, the proper trip speed for the Standard being reviewed.

Table 1—Driver Trip Speeds

Driver Type

Trip Speed(% of Maximum

Continuous Speed)Steam TurbineNEMA Class Aa 115%NEMA Class B, C, Da 110%

Gas Turbine 105%

5/6/2023

5/6/2023 Page 47 of 99

Variable-Speed Motor 110%Constant-Speed Motor 100%

Reciprocating Engine 110%

aIndicates governor class as specified in NEMA SM 23

6.1.10 The arrangement of the equipment, including piping and auxiliaries, shall be developed jointly by the purchaser and the vendor. The arrangement shall provide adequate clearance areas and safe access for operation and maintenance.

Discussion: This gives the purchaser the right to critique the arrangement of the equipment and define "adequate clearance" and “safe access”.

•6.1.11 Electrical Classification

6.1.11.1 Locations for installed equipment can be classified as hazardous electrical areas or they can be unclassified. An unclassified area is considered non-hazardous; therefore, motors, electrical instrumentation, equipment, components, and electrical installations for unclassified areas are not governed by hazardous area electrical codes.

• 6.1.11.2 If an installation location is classified as hazardous, motors, electrical instrumentation, equipment , components, and electrical installations shall be suitable for the hazardous electrical area classification designation as specified.

• 6.1.11.3 All applicable electrical codes shall be specified. Local electrical codes that apply shall be provided by the purchaser upon request.

6.1.11.4 Electrical codes vary by installation location. Refer to table XXX for a tabulation of common hazardous area electrical codes in use.

Common Hazardous Area Electrical Codes

Standards Org. Codes Where Used

Hazardous Electrical Area Classification

DesignationIECCENELEC

IEC 60079EN 60079

European Union (EU) countries & worldwide, except U.S.

Zone, Gas Group, Temperature Class

European Union (EU)

ATEXDirective 94/9/EC

Required, in addition to IEC, in EU countries only. May be requested in other countries.

Equipment Group, Category

5/6/2023

5/6/2023 Page 48 of 99

NEC®

NFPA 70Sections 500-502, 504

United States Class, Division, Group, Temperature Class

NEC®NFPA 70Section 505

United States Class I, Zone, Gas Group, Temperature Class

CEC®

CSA C22.1-06, Section 18

Canada

Primary: Adoption of IEC - Zone, Gas Group, Temperature Class In Appendix: Class, Division, Group, Temperature Class

Table XXXIEC: International Electrotechnical CommissionCENELEC: European Committee for Electrotechnical StandardizationATEX: “Atmospheres Explosibles”, “Equipment intended for use in Potentially Explosive Atmospheres” NEC®: National Electrical Code®, published by National Fire Protection Association, Inc. (NFPA)CEC®: Canadian Electrical Code®, published by Canadian Standards Association (CSA)

NOTE – 1 The ATEX directive, 94/9/EC, became effective on June 30, 2003, and applies to all equipment (mechanical and electrical) that is intended for use in a potentially explosive atmosphere, in the European Economic Area . While not a specific electrical code, it is listed in the table because most electrical products cannot be put into use in a hazardous area in the European Economic Area without ATEX certification. Also, mechanical products, which are used in the EU, in a hazardous area, are required to conform to the ATEX directive. The ATEX directive defines categories, which determine the approach used to obtain ATEX certification. Electrical and mechanical equipment are required to meet the essential health and safety requirements set forth in the ATEX directive.

NOTE - 2 Refer to Annex XXX for a comparison of electrical area classifications for various governing bodies.

Discussion: For a detailed discussion on adoption of API standards in Europe, EU Directives and ATEX refer to SP Informative Annex 9.

Discussion: Article 500 describes Area classification in general, Article 501 covers classification for Class 1 locations, Article 502 covers class 2 locations, Article 503 covers class 3 locations [Dust & grain mils (possibly coal or coke dust in coker units) not in API scope so don’t include], Article 504 covers intrensically safe systems and article 505 addresses Zone classification systems. (European method of classification)

API document RP 500 is for the division method and 505 is for the zone method of classification. The NFPA explain the various the concepts of area classification . The API documents explain how to do the area classification . The NFPA tells you what type of equipment is acceptable in each area.

5/6/2023

5/6/2023 Page 49 of 99

The reference standards differ in some cases in the definition between explosion proof and flame proof. In addition, NFPA 70 instructs how to draw the boundaries for the different zones, several of the other references only define the zones but do not tell where to place their boundaries.

The vendor is required to request from the purchaser any governmental requirements. The purchaser generally has other equipment at the site, and is more familiar with the local governmental regulations. Refer also to 5.2 Statutory requirements.

6.1.12 Oil reservoirs and housings that enclose moving lubricated parts such as bearings, shaft seals, highly polished parts, instruments, and control elements shall be designed to minimize contamination by moisture, dust, and other foreign matter during periods of operation and idleness.

6.1.13 All equipment shall be designed to permit rapid and economical maintenance. Major parts such as casing components and bearing housings shall be designed and manufactured to ensure accurate alignment on reassembly.

NOTE - This can be accomplished by the use of shouldering, cylindrical dowels or keys.

Discussion: TF should consider highlighting other components which are only specific to there specific standard such as cylinders and distance pieces for reciprocating compressors. Cylindrical dowels are required in lieu of tapered dowels since cylindrical dowels are positive locating. Tapered dowels can be started and driven home if the dowel holes in the mating components don't match exactly.

Last sentence in 6.1.13 was made a Note, since it describes how the requirement of the paragraph can be accomplished.

6.1.14 The equipment (machine, driver, and ancillary equipment) shall perform on the test stand(s) and on their permanent foundation within the specified acceptance criteria. After installation, the performance of the combined units shall be the joint responsibility of the purchaser and the vendor who has unit responsibility.

Discussion: This does not imply that the equipment has to be tested together. Where ever the equipment is tested, it must meet the specified acceptance criteria.

6.1.15 Many factors can adversely affect site performance. These factors include such items as piping loads, alignment at operating conditions, supporting structure, handling during shipment, and handling and assembly at the site. To minimize the influence of these factors, the vendor shall review and comment on the purchaser's piping and foundation drawings. When If specified, the vendor's representative shall witness:a. A check of the piping alignment performed by unfastening the major flanged connections of the equipment.

5/6/2023

5/6/2023 Page 50 of 99

b. The initial shaft alignment check.c. Shaft alignment at operating temperature.

6.1.16 The equipment, including all auxiliaries, shall be suitable for operation under the environmental conditions specified. These conditions shall include whether the installation is indoors (heated or unheated) or outdoors (with or without a roof), maximum and minimum temperatures, unusual humidity, and dusty or corrosive conditions.

Discussion: Although paragraph 6.1.1 states that the equipment is to be designed to operate at least 3 years continuously, it was felt that the tie-in with the environmental conditions outlined in this paragraph (R-20) was weak. The paragraph was thus revised.

6.1.17 The equipment, including all auxiliaries, shall be suitable for operation, using the utility stream conditions specified.Note to Task Force Chairmen: Space for all utility streams and there operating ranges should appear on the data sheets. The streams should agree with the listing in Section 3 Table XXX for the auxiliary piping streams.

6.1.18 Spare and replacement parts for the machine and all furnished auxiliaries shall meet all the criteria of this standard.NOTE - Refer to 5.3.4 for parts list requirements.

Discussion: The term “spare parts” could be applied to only those ordered with the original order. Parts ordered later as the result of the initial spares being used in many cases are not produced to the same standards and QC requirements as was the original "spare parts"but should. Therefore the term replacement parts was introduced to cover these subsequent parts. The standard now requires these parts to meet the same criteria as the original “spare Parts”.

Note to TF Chairs : The following paragraphs on bolting was moved from 6.2 Pressure casing section since these paragraphs are applicable to any bolting supplied.

6.1.19 Bolting and Threads

Task Force Chairs: For a complete description of bolting , threads and the background on this section refer to SP Informative Annex 7

• 6.1.19.1 The threading shall conform to ISO 261, or ASME B1.1. as specified. [API 672 / 610 / 617]. NOTE 1- ISO 261 covers general metric screw threads and ASME B 1.1 covers general inch series screw threads.

NOTE 2- For the purposes of this provision, ASME B 1.13M is equivalent to ISO 261.

NOTE 3- Glossary of terms for screw threads can be found in ASME B 18.12-2001

NOTE 4- J profile threads are covered in 6.1.19.2

5/6/2023

5/6/2023 Page 51 of 99

Discussion: ISO 261 (Metric) & ASME B 1.1 (Inch) are general standards covering screw threads. ISO and ASME have excerpted segments of these generalized specifications and generated standards only addressing commercial fasteners (Nuts & Bolts). Metric commercial fasteners are covered in ISO 262 and ASME B 1.18M.

So what actually is the difference between the general screw thread specification such as ASME B 1.13M and the one covering fasteners ASME B 1.18M? The answer to this is found in one of the introductory paragraphs of ASME B 1.18M which states:“Due to the specific application of this document to standard fastener sizes, ANSI/ASME B1.13M (the general specification) shall be used for other diameter-pitch combinations, other tolerance classes, long and short thread engagement lengths, left-hand threads, and multiple start threads. ANSI/ASME B1.13M shall be used where the IS0 68 profile dimensioning practices are required.”

In order to reduce the number of standards referenced, SP 6.1.19.1.1 and 6.1.19.1.2 uses the generalized ISO and ASME specifications and adds requirements and caveats specific to fasteners. Note that the ASME metric fastener specification B 1.18M has a slightly different external root than the generalized ASME Metric specification B 1.13 or ISO 261 or 262. Threads produced to B1.18M are functionally interchangeable with IS0 and ANSI B1.13M threads of the same size and tolerance class. However, threads produced to the IS0 and ANSI B1.13M standards may not meet all requirements for threads produced to this Standard ASME B1.18M.

6.1.19.1.1 When ASME B1.1 threads have been specified, the thread series shall be variable pitch series UNC or UNRC, or constant pitch series 4, 6, or 8-UN or UNR. Diameters shall be selected from Table 2 Column 1 of ASME B 1.1. The threads shall be Class 2 for bolting, studs and nuts. For other threads and nuts they shall be Class 2 or 3.

In order to prevent galling, when ASME B 1.1 Class 3 external threads are used, the tolerance for maximum material conditions shall be modified to prevent zero clearance.

NOTE 1 - ASME B1.1 Class 3 tolerance for the OD of the external thread and the ID of the internal thread results in zero clearances. This has resulted in galling and inability to disengage the mating components.

NOTE 2 - Internal threads do not have any allowance, and therefore even if a Class 2 nut is used with a Class 3 external thread, metal-to-metal at maximum material conditions can develop.

6.1.19.1.2 When ISO 261 has been specified, the thread series shall be coarse or 3, 4, 6 or 8 pitch. Diameters shall be selected from Table 2 Column 1 of ISO 261. The threads shall be Class 6g for bolting and studs, and Class 6H for nuts. For other threads they shall be Class 6g or 4h for external threads and Class 6H or 5H for internal threads.

5/6/2023

5/6/2023 Page 52 of 99

In order to prevent galling, when ISO class h/H position is specified for mating components, the tolerance for maximum material conditions shall be modified to prevent zero clearance.

NOTE 1- ISO position h/H clearance for the OD of the external thread and the ID of the internal thread can result in 0 clearance between the mating components. This has resulted in galling and inability to disengage the mating components.

NOTE 2- Internal threads position G in the ISO system have an allowance, and therefore a nut using position G can be used with a position h external thread, and not develop metal-to-metal contact.

Discussion: This is different than ASME where interference will still exist if a Class 2 nut is used with a Class 3 stud.

Although ISO labels the 3, 4 & 6 Pitch series as “fine” they are approximately equivalent to the constant pitch ASME UN series which we allow. Refer to Table 7-2 and 7-3 in this Annex for the complete tabulation of all diameters and pitches for the ASME and ISO threads covered by ISO 261 and ASME B 1.1.

A comparison of the ISO “Fine” 3, 4, & 6 pitch threads to the ASME UN is presented in Table 7-0. This is the reason to include the ISO 3, 4, & 6 pitch series, even though they are labeled “fine” in Table 2 in ISO 261

Note to Task forces: A complete description of the ASME and ISO thread systems can be found in Informative Annex 7

5/6/2023

5/6/2023 Page 53 of 99

Note to Task Force Chairmen: Include UNJ threads when the equipment covered by the specification normally uses this type of thread i.e threads with large root diameters. The ASME or ISO standards do not require these threads to be manufactured by rolling and therefore rolled threads should be specified in the API paragraph. Rolled J threads are typically found on recip rods, and possibly axial compressors and gas turbine tie bolts .

• 6.1.19.2 When J profile threads are used, they shall comply with ISO 5855-1-1988 or ASME B 1.15 -1995 as specified.

NOTE 1- ISO 5855-1 -1998 is the general metric J profile screw threads and ASME B 1.15-1995 covers inch J profile screw threads.

NOTE 2 - For the purposes of this provision, ASME B 1.21M-1978 is equivalent to ISO 5855-1- 1988 and ISO 5855-2-1988.

Discussion: ISO 5855-1 is the general ISO specification for J threads. ISO 5855-2 covers requirements for bolts and nuts up to 33 mm and references ISO 5855-1.

6.1.19.2.1 When ISO 5855-1-1988 has been specified, the thread series shall be course or 3 pitch as required by Table 2 of ASME B 1.21M-1978. Diameters shall be selected from Table 2 Column 1 of ASME B 1.21M -1978. The threads shall be Class 4h6h for bolting studs and 4H5H for nuts. Threads other than those for fasteners shall be Class 6g or 4h for external threads and Class 6H or 5H for internal threads. In order to prevent galling, when ISO class h/H position is specified for mating components, the tolerance for maximum material conditions shall be modified to prevent zero clearance.

NOTE 1- ISO position h/H clearance for the OD of the external thread and the ID of the internal thread can result in 0 clearances. This has resulted in galling and inability to disengage the mating components.

NOTE 2- Internal threads position G in the ISO system have an allowance, and therefore a nut using position G can be used with a position h external thread, and not develop metal-to-metal contact

Discussion: Thread series: Unlike ISO 261, ISO 5855-1-1998 does not have a table listing course, and fine pitches, nor preferred diameters. ASME B 1.21M-1978 has these tabulations and is therefore referenced for consistency. ASME B 1.21M-1978 does not have 4, 6, or 8 pitch threads as does the general metric threads of ISO 261.

Discussion: Diameters : ISO 5855-1-1998 Table 2 does not differentiate between 1st and 2ed choice diameters. Table 2 has only one list which spells out the allowable combinations of diameters and pitches.

ISO 261 (which covers general metric screw threads) has 3 columns of diameters, Column 1 is the first choice, Column 2 is the second choice and Column 3 is the third choice. This is why in 6.1.1.19.1 Column 1 is referenced when using ISO 261.

ASME B 1.21M-1978 (which covers J metric threads) does list preferred diameters. In Table 2 of ASME B 1.21M-1978 there are two Nominal Diameter columns. Column 1 is the 1st

5/6/2023

5/6/2023 Page 54 of 99

choice and Column 2 is the second choice. To keep ISO 5855-1-1998 and ASME B 1.21 M-1978 similar, the preferred diameters listed in column 1 of ASME B 1.21M-1978 are required in 6.1.19.2.1. All threads referenced in ASME B 1.21M-1978 appear in ISO 5855.

Discussion: Thread Class : The ISO and ASME specifications’ covering J threads place a position and grade (i.e. Class) on the pitch diameter in addition to the major and minor diameters. This does not agree with the “normal” metric threads which assigns the same position & grade to both the pitch diameter and major and minor thread dimension. A comparison of the positions and grades as required by the various specifications are tabulated below.

SP 6.1.19.2.1 has defaulted to the requirements of ISO 5855-2 for the class of threads for bolts and nuts. i.e. 4h6h for bolting studs and 4H5H for nuts

SP 6.1.19.2.1 defaulted to the requirements of ISO 261 for threads other than bolting and nuts i.e. 6g or 4h for external threads and Class 6H or 5H for internal threads.

ISO 5855-2 threads were designed primarily for fasteners used on aircraft and therefore should be ready available in the 4h6h and 4H5H class. It did not appear justifiable to require this split class designation to apply to threads other than bolts and nuts. Therefore threads other than those used for fasteners have a class applied which is the same as that required by ISO 261. ISO 261 requires Class 6g or 4h for external threads and Class 6H or 5H for internal threads. These classes are generally equivalent to the ASME class 2 & 3.

Discussion: A comparison of the different classes of fits is tabulated the following table.

5/6/2023

5/6/2023 Page 55 of 99

5/6/2023

5/6/2023 Page 56 of 99

5/6/2023

5/6/2023 Page 57 of 99

6.1.19.2.2 When ASME B1.15 (Inch series) threads have been specified, the thread series shall be variable pitch series UNJC or constant pitch series 4, 6, or 8-UNJ. The threads shall be Class 2 or 3. Diameters shall be selected from Table 2 Column 1 of ASME B 1.15. In order to prevent galling, when ASME B 1.15 Class 3 external threads are used, the tolerance for maximum material conditions shall be modified to prevent zero clearance.

NOTE 1- ASME B1.15 Class 3 tolerance for the OD of the external thread and the ID of the internal thread results in zero clearances. This has resulted in galling and inability to disengage the mating components.

NOTE 2- Internal threads do not have any allowance, and therefore even if a Class 2 nut is used with a Class 3 external thread, metal-to-metal at maximum material conditions can develop.

Discussion: UNJ thread series does not have a constant 4 or 6 pitch series threads like the UN series has – refer to paragraph 6.1.19.1) Discussion: Defaulted to class 2 or 3 since these are generally special threads and class 3 threads are generally available for bolting since this class is required for the military. In paragraph 6.1.1.19.1 the bolting is required to be Class 2 for bolting, studs and nuts. For other threads and nuts they shall be Class 2 or 3.

6.1.19.2.3 When J profile threads are used, external threads shall be formed by rolling.

6.1.19.3 Gaging

6.1.19.3.1 Inspection or gaging requirements of threads shall be identified in accordance with ASME B 1.1 – 1989 Section 6 - Screw Thread Designation.

6.1.19.3.2 All threaded products shall be visually inspected for gross defects. This visual inspection shall be made without magnification and is intended to detect such gross defects as missing or incomplete threads, defective thread profile, torn or ruptured surfaces and cracks, etc [ASME B 1.3M 1986]

6.1.19.3.3 All threads used to join components of a built-up rotor configuration, or on running gear components of reciprocating equipment shall be inspected in accordance with ASME B 1.3 M – 1986 differential thread gaging system 22. The pitch diameter and cumulative variation of thread characteristics such as lead, flank angle, taper, and roundness (functional diameter) shall be measured at each end of the thread and shall not exceed the tolerance on pitch diameter. The major diameter of external threads and minor diameter of internal threads shall also be measured at each end of the thread and shall not exceed the tolerances for the specification specified in 6.1.19.1. The root radius of J profile threads shall be measured and shall not exceed the requirements of ASME B 1.21 (Metric series) or ASME B 1.15 (Inch series).

• 6.1.19.3.3.1 When specified, the individual errors for lead, flank angle, taper, and roundness shall be determined and shall not exceed ASME or ISO governing thread specification.

5/6/2023

5/6/2023 Page 58 of 99

6.1.19.3.4 Where one tie-bolt is used to join components of a built-up rotor configuration, the threads shall be inspected in accordance with ASME B 1.3 M – 1986 differential thread gaging system 23. The pitch diameter and cumulative variation of thread characteristics such as lead, flank angle, taper, and roundness (functional diameter) shall be measured at each end of the thread and there difference shall not exceed 50% of the tolerance on pitch diameter. The major diameter of external threads and minor diameter of internal threads shall also be measured at each end of the thread and shall not exceed the tolerances for the specification specified in 6.1.19.1. The root radius of J profile threads shall be measured and shall not exceed the requirements of ASME B 1.21 (Metric series) or ASME B 1.15 (Inch series).

6.1.19.3.5 Threads used to secure the positioning of components on rotors shall be inspected in accordance with 6.1.19.3.3 using Go, No-Go gaging when thread length is less than 1 ½ times the gage length. If greater than 1½ times the gage length they shall be checked in accordance with ASME B 1.3M-1986 gaging system 22 using differential gaging. The pitch diameter and cumulative variation of thread characteristics such as lead, flank angle, taper, and roundness (functional diameter) shall be measured and shall not exceed the tolerance on pitch diameter. The major diameter of all external threads and minor diameter of all internal threads shall also be measured and shall not exceed the tolerances of the specification specified in 6.1.19.1

6.1.19.3.6 Threads used in joining casing pressure containing components shall be inspected in accordance with 6.1.19.3.6.1 or 6.1.19.3.6.2

6.1.19.3.6.1 Commercial fasteners shall be manufactured in accordance with the requirements of ASME B 18.18.2M or shall be procured from distributors having quality plans in accordance with ASME B 18.18.2M

6.1.19.3.6.2 All threads used on non-commercial fasteners shall be manufactured in accordance with ASME B 1.3M-1986 thread gaging system 21 using GO, NO-GO gaging.

6.1.19.3.7 All threads used on non-commercial studs inserted into blind holes shall be manufactured in accordance with ASME B 1.3M-1986 gaging system 22 using differential gaging. The pitch diameter and cumulative variation of thread characteristics such as lead, flank angle, taper, and roundness (functional diameter) shall be measured and shall not exceed the tolerance on pitch diameter. The major diameter of all external threads and minor diameter of all internal threads shall also be measured and shall not exceed the tolerances of the specification specified in 6.1.19.1

5/6/2023

5/6/2023 Page 59 of 99

6.1.19.4 Adequate clearance shall be provided at all bolting locations to permit the use of socket or box wrenches.

6.1.19.5 Internal socket-type, slotted-nut, or spanner-type bolting shall not be used unless approved by the purchaser.NOTE - For limited space locations, integrally flanged fastener may be required.

Discussion: This type of bolting has a bolt head with a recess for wrench device such as a 6 sided socket head cap screw or a star head (Torx) head configuration. [Technical inquiry 612-01-04]

6.1.19.6 Manufacturers marking shall be located on all fasteners 6 mm (1/4") and larger (excluding washers and headless set screws). For studs, the marking shall be on the nut end of the exposed stud end.NOTE - A set screw is a headless screw with an internal hex opening on one end.

Discussion: U.S. Government requires that all fasteners be identified, except as noted. It may be an ASTM or a manufacturers identifying mark. This is standard practice with fastener suppliers and allows the user to confirm all fasteners have been properly sourced.

• 6.1.20 Fluids that are flammable, hazardous, or toxic shall be identified by the purchaser. [610 9th edition]

TF Chair: Include a box (s) on the data sheets for the purchaser to fulfill this requirement.

6.2 PRESSURE CASINGS (OR CYLINDERS)

6.2.1 The pressure casing shall be designed in accordance with 6.2.1.1 or 6.2.1.2 as selected by the Vendor and the casing joint bolting shall be in accordance with 6.2.1.3 to:

A) Operate without leakage or internal contact between rotating and stationary components while subject simultaneously to the MAWP ( and corresponding temperature) and the worst case combination of maximum allowable nozzle loads applied to all nozzles.

B) Withstand the hydrostatic test.

6.2.1.1 The allowable tensile stress used in the design of the pressure casing (excluding bolting) for any material shall not exceed 25% of the minimum ultimate tensile strength for that material at the maximum specified operating temperature . For cast materials, the allowable tensile stress shall be multiplied by the appropriate casting factor as shown in Table 1

5/6/2023

5/6/2023 Page 60 of 99

Table 1 — Material Casting factors

Type of NDE Casting factor

Visual, magnetic particle and/or liquid penetrant

0.8

Spot radiography 0.9Ultrasonic 0.9

Full radiography 1.0

DISCUSSION: This table is applicable for castings used in turbomachinery such as cast irons and steels and in accordance with paragraph 6.2.1.1.

Discussion: 6.2.1.1. does not account for creep as required by the Code, however almost all of the SOME mechanical equipment operating temperatures are below the temperature at which creep starts. The code starts to decrease the allowable tensile stress at about 600 F which only affects high temperature steam turbines and gas turbines. In gas turbine design creep is generally allplied to the blades and discs and not the casing. We will therefore disregard the creep and degradation above 600 F.

6.2.1.2 Pressure containing components may be designed with the aid of finite element analysis provided that the value of the stress intensity reflects a requirement to perfom a hydrotest at 150% of MAWP.

Discussion: The code was revised to reduce the hydrotest pressure from 150% MAWP to 125% MAWP (in approximately 1990). The allowable stress levels of materials were increased to maintain the same hydrotest stress level at 125% MAWP hydrotest as previously occurred at 150% MAWP. This allowed pressure vessels to be designed to higher stress levels at MAWP. SPTF did not go along with the ASME method since we did not want to increase the casing stress levels to a region were there was no experience. Many of these casings are cast and have complicated shapes.

6.2.1.3 A corrosion allowance of at least 3mm (0.12in) shall be added to the casing thickness used in 6.2.1.1 or 6.2.1.2. This corrosion allowance shall also be added to all auxiliary connections exposed to the same fluid as the pressure containing casing. NOTE - In general deflection is the determining consideration in the design of casings. Ultimate tensile or yield strength is seldom the limiting factor.

Note to TF Chairs: Review 6.2.1.3 auxiliary connection requirement inlight of shaft end seals which use the process fluid as a buffer fluid.

Discussion: The previous standard paragraph allowed for various stress values depending if Division 1 or 2 methods of calculations are used. Division 1 requires fairly simple calculations and conversely has lower allowable stress values than Division 2 more rigorous methods The 6.2.1.1 mandating 25% of the ultimate tensile is intended for Division 1 code calculations and

5/6/2023

5/6/2023 Page 61 of 99

the Stress intensity requirements of 6.2.1.2 refer to Division 2 calculations. It is left up to the manufacturer which method will be used.

Although the code exempts mechanical rotating equipment, the requirement has been repeated for clarity i.e. the last paragraph from 610 has been added. The following is excerpted from ASME Section VIII Division 1 scope paragraph U-1(c)(2) “Based on the committees consideration, the following classes of vessels are not included in the scope of this Division...(c) pressure containers of rotating or reciprocating mechanical devices, such as pumps, compressors, turbines, generators, engines, and hydraulic or pneumatic cylinders...”

6.2.1.4 For casing joint bolting, the allowable tensile stress, as determined in 6.2.1.1 shall be used to determine the total bolting area based on hydrostatic load and gasket preload as applicable. The bolting preload stress shall not exceed 75% of the bolting material mimimum yield.NOTE 1 - Preloading the bolting is required to prevent unloading the bolted joint due to cyclic operation.

 6.2.1.5 The manufacturer shall state the source of the material properties used in 6.2.1.1 or 6.2.1.2, such as ASTM, ASME Pressure vessel code etc., as well as the casting factors applied in his proposal.

6.2.1.6 Manufacturing data report forms, third party inspections, and stamping as specified in the ASME code are not required.

6.2.2 The maximum allowable working pressure of the casing (or cylinder) shall be at least equal to the specified relief valve set pressure. If a relief valve is not specified, the maximum allowable working pressure shall be at least 125% of the maximum specified discharge pressure gauge but not less than the maximum discharge pressure as defined in 3.21. The maximum allowable working pressure is a function of the design of the casing. The maximum allowable working pressure for a casing design shall not be reduced based on the particular application requirements. [Spring refining meeting 2003]

Unless otherwise specified, system pressure protection shall be furnished by the purchaser. (Can’t specify anything in a note. Made a part of the standard paragraph.

.

Discussion: The relief valve cracks open at the relief valve set pressure and is fully open at a higher pressure. This pressure rise is called accumulation and is typically 10% of the relief valve setting. It is improper to set the maximum allowable working pressure at the relief valve setting plus accumulation since the ASME code takes this rise into account when calculating allowable stresses.

In order to prevent relieving product through relief valves, systems are generally designed to withstand the highest pressure which the centrifugal rotating equipment can develop. Systems containing positive displacement pumps or compressors require relief valves.

5/6/2023

5/6/2023 Page 62 of 99

The maximum SPECIFIED discharge pressure is the highest discharge pressure specified by the purchaser. The 125% is applied to this pressure to obtain a condition which generally encompasses the entire operating envelope of a centrifugal piece of equipment. This approach is used when other conditions which can effect the discharge pressure are not known. When additional information concerning the operating conditions are known, these can be taken into account as requires by 3.18??? to calculate a more accurate maximum discharge pressure.

6.2.3 Casings shall not be designed for more than one maximum allowable pressure level (split-pressure-level casings) unless approved by the purchaser. If approved, the vendor shall define the physical limits and the maximum allowable working pressure of each part of the casing.

6.2.4 The main joint of axially split casings shall use a metal-to-metal joint that is tightly maintained by bolting. The joint shall be sealed with a compound that is compatible with the fluids to be handled. Gaskets (including string type) shall not be used.

The main joints of radially split casings, may incorporate a gasket. Such gaskets shall be fully confined.

Discussion: String type gaskets can cause indentations in the joint when the flange is tightened. This groove can subsequently cause a leakage path. The preferred joint is a metal-to-metal joint. Did not include the use of O-rings since they are not common in the equipment purchased by US users. Metal to metal joints provide more sealing area and are more reliable since they do not depend upon the proper design of an O ring grove. Metal to metal joints also eliminate the need for a special O ring spare part.

However for certain types of equipment, alternatives have been allowed if the manufacturers and users can indicate successful field experience. Where alternatives have been allowed the vendor has to notify the purchaser. Thus API 617 allows O rings on the horizontal joint only with purchasers approval and API 610 requires the vender to notify the purchaser if composition sheet gasket is used on the horizontal joint.

6.2.5 Each axially split casing shall be sufficiently rigid to allow removal and replacement of its upper half without disturbing rotor-to-casing running clearances.

Discussion: Rotor-to-casing running clearances are checked with the top half of the casing off. These clearances need to be the same when the top of the casing is installed.

6.2.6 Casings and supports shall be designed to have sufficient strength and rigidity to limit any change in the relative position of the shaft ends at the coupling flange, caused by the worst combination of allowable pressure, torque, and piping forces and moments, to 50 µm (0.002 in).

Discussion: This paragraph specifically eliminates the change of alignment due to thermal growth which can be cold offset. The intent of this paragraph is to have heavy duty equipment (and supports) which will not deflect during operation and possibly rub, or adversely affect

5/6/2023

5/6/2023 Page 63 of 99

bearing or seals. In some cases, the coupling movement is monitored as the main flanges are bolted to the piping. Movement of the coupling under these conditions generally indicates excessive pipe strain on the equipment.

6.2.7 Supports and the design of jack screws and their attachments shall be rigid enough to permit the machine to be moved by the use of its lateral and axial jackscrews.

6.2.8 The use of threaded holes in pressure parts shall be minimized. To prevent leakage in pressure sections of casings, metal equal to at least 12mm (1/2 in), in addition to the corrosion allowance, shall be left around and below the bottom of drilled and threaded holes. The depth of the threaded holes shall be at least 1.5 times the stud diameter. [API 617 & 682]

6.2.9 Bolting shall be furnished as specified in 6.2.9.1 through 6.2.9.2

6.2.9.1 Studs shall be supplied on the main joint of axially split casings and bolted end covers of radially split casings.

Studs shall be used instead of cap screws, on all other joints, except where hexagonal head cap screws are essential for assembly purposes and have been approved by the purchaser.

Discussion: Other types of fasteners may also be used if approved by the purchaser—Refer to 6.1.19.3

Studs are required instead of bolting since the bolting screws into the casing lower half and may strip the threads in the casing when being removed. With a stud-nut combination, the stud remains in the bottom half of the casing and the nut is removed from the stud. It is easier to rework a stud than the casing.

Thru bolt design (stud with a nut on each end) is provided for certain applications and is also acceptable. Thru bolting requires the bottom half of the casing also be spot faced.

6.2.9.2 If specified, the main casing (or cylinder) joint studs and nuts shall be designed for the use of hydraulic bolt tensioning. Procedures and extent of special tooling provided by the vendor shall be mutually agreed upon.

Discussion: Hydraulic tensioning requires the stud to be stretched and the nut screwed into position. This generally requires the stud to extend through and above the nut. i.e. castle type nuts can not be used.

Hydraulic torqing however, generally does not require special studs or nuts. In hydraulic torquing, most of the energy goes into overcoming the thread friction. A lubricant which gives a known coefficient of friction is required if hydraulic torquing is used.

6.2.10 Jackscrews, guide rods, cylindrical casing-alignment dowels and/or other appropriate devices shall be provided to facilitate disassembly and reassembly. Guide rods shall be of sufficient length to prevent damage to the internals or casing studs by the casing during disassembly and reassembly. Lifting lugs or eyebolts shall be provided for lifting only the top half of the casing.

5/6/2023

5/6/2023 Page 64 of 99

When jackscrews are used as a means of parting contacting faces, one of the faces shall be relieved (counterbored or recessed) to prevent a leaking joint or an improper fit caused by marring of the face.

Discussion: “Other appropriate devices” could be extraction rigs for vertically split equipment, or rollers on the bundles of these machines.

6.2.11 Mounting surfaces shall meet the following criteria:

1. They shall be machined to a finish of 6,3 μm (250 μin) Ra or better.2. Each mounting surface shall be machined within a flatness of 40 μm per linear meter (0.0005 inches per linear foot) of mounting surface.3. They shall be in the same horizontal plane within 25 μm (0.001 in) to prevent a soft foot. 4. Different mounting planes shall be parallel to each other within 50 m (0.002 in).

5. The upper machined or spot faced surface shall be parallel to the mounting surface.Hold-down bolt holes shall be drilled perpendicular to the mounting surface or surfaces, machined or spot faced to a diameter three times that of the bolt and to allow for equipment alignment, be 15 mm (1/2") larger in diameter than the hold down bolt. [API 677]

Discussion: Removed reference to foundation bolts since this is the casing section and as previously discussed in the definitions, foundation bolts only attach to the mounting plates, not the casing.

Paragraph 6.2.11.3 addresses machining of individual feet.

Paragraph 6.2.11.4 addresses machining feet which, by design, are not in the same place such as wobble foot on turbines.

Discussion: refer to 7.4.2.9 for machining of the baseplate mounting surfaces.

6.2.12 The equipment feet shall be provided with vertical jackscrews and shall be drilled with pilot holes that are accessible for use in final doweling.

6.3 CASING (OR CYLINDER) APPURTENANCES

6.4 PRESSURE CASING (OR CYLINDER) CONNECTIONS [3.6.1.2]

6.4.1 All openings or nozzles for piping connections on pressure casings (or cylinders) shall be DN 20 (NPS 3/4) or larger and shall be in accordance with ISO 6708:1995. Sizes DN 32, DN 65, DN 90, DN 125, DN 175 and DN 225 (NPS 1 1/4, 2 1/2 3-1/2, 5, 7, and 9) shall not be used.

6.4.2 All connections shall be flanged or machined and studded, except where threaded connections are permitted by 6.4.5. All connections shall be suitable for the maximum allowable working pressure of the casing as defined in 3.16. Main inlet and outlet process connections shall

5/6/2023

5/6/2023 Page 65 of 99

be oriented as specified. Flanged connections may be integral with the casing (or cylinder) or, for casings (cylinders) of weldable material, may be formed by a socket-welded or butt-welded pipe nipple or transition piece, and shall terminate with a welding-neck or socket-weld flange.

Discussion: The configuration of the flange connections and does not allow van-stone type flanges.

6.4.3 Connections welded to the casing (or cylinder) shall meet the material requirements of the casing (or cylinder), including impact values and temperature pressure rating , rather than the requirements of the connected piping (see 6.11.4.5). All welding of connections shall be completed before the casing (or cylinder) is hydrostatically tested (see 8.3.2). [610]

6.4.4 Butt welded connections, size DN 40 (NPS 1-1/2) and smaller, shall be reinforced by using forged welding inserts or gussets.

Discussion: Typically these connections are required to support heavy valves which can cause fatigue failure if the connections are not properly reinforced.

6.4.5 For connections other than main process connections, if flanged or machined and studded openings are impractical, threaded connections for pipe sizes not exceeding DN 40 (NPS 1-1 /2) may be used with purchasers approval as follows:a. On non-weldable materials, such as cast iron;b. Where essential for maintenance (disassembly and assembly).

6.4.6 Pipe nipples screwed or welded to the casing should not be more than 150 mm (6 in) long and shall be a minimum of Schedule 160 seamless for sizes DN 25 (NPS 1) and smaller and a minimum of Schedule 80 for DN 40(NPS 1-1/2).

Discussion: The term "should" is used instead of "shall" in this paragraph since it is desirable, but not always possible, to limit nipple length because of the specific arrangement of the equipment.

6.4.7 The nipple and flange materials shall meet the requirements of 6.4.3.

• 6.4.8 Threaded openings for tapered pipe threads shall conform to ISO 7- l : 1994 or ASME B 1.20.1 as specified. If ISO 7- 1: 1994 has been specified, tapered or straight internal threads shall also be specified. Bosses for pipe threads shall conform to ASME B 16.5.

Discussion: Refer to 3.37 and 7.6.1.7 for the discussion of ASME B 1.20.1 and US tapered pipe threads.

ISO 7 Part 1: 1994 address threads and do not cover bosses. Threads and bosses are both covered in ASME B 16.5

ISO 7 Part 2:2000 addresses Gaging and is not required to be referenced.

5/6/2023

5/6/2023 Page 66 of 99

ISO 7 Part : 1994 specifies the threads for joints made pressure-tight by the mating of the threads. These threads are taper external ,parallel internal or taper internal and are intended for use with pipes suitable for threading and for valves, fittings or other pipeline equipment interconnected by threaded joints.

ASME B 16.5 states: ..”Threaded flanges shall have an American National Standard taper pipe thread conforming to ASME B 1.20.1.” Figure 6 of ASME B 1.20.1 gives sizes for bosses.

Discussion: ANSI reference has been remove in the SP since the latest issue of the source document such as ASME or AGMA specification may not have been adopted by ANSI and by referencing the ANSI version the latest revision is excluded. ANSI adoption does not change the base ASME document. In addition, ISO will go through and scratch all the reference to ANSI (For some unknown reason).

6.4.9 Threaded connections shall not be seal welded.

Discussion: Since threaded connections are allowed only for non-weldable materials, such as cast iron, and where essential for maintenance (6.4.5), there is no need to seal weld connections.

6.4.10 Threaded openings not required to be connected to piping shall be plugged with solid, round-head steel plugs in accordance with ASME B16.11. As a minimum, these plugs shall meet the material requirements of the pressure casing (or cylinder). Plugs that may later require removal shall be of a corrosion-resistant material. Plastic plugs are not permitted.

Discussion: A suitable thread lubricant shall meet the proper temperature specification for the application.

6.4.11 A process compatible thread lubricant of proper temperature specification shall be used on all threaded connections. Thread tape shall not be used. [614]

Discussion: Moved from 6.4.10 and made a separate paragraph since instrument tubing has threads, in add ition to screwed connections.

6.4.11 Flanges

Discussion: Refer to Informative Annex 1 for detailed disussion and tables explaining the differences between ISO and ASME flanges. These discussions and tables were too voluminous to include in the body of the Standard Paragraphs.

• 6.4.11.1 Flanges shall conform to ISO 7005-1: 1992 Series 1, including Annex D & E or 7005-2:1988 Series 1 or ASME B16.1, B16.5, B16.42 or B16.47 Series B), as specified, except as specified in 6.4.11.2 through 6.4.11.8 [ API 617].

5/6/2023

5/6/2023 Page 67 of 99

NOTE 1- ISO 7005-1:1992 (steel flanges) PN 20, 50, 110, 150, 260, 420 are designed to be interchangeable with ASME B16.5 and MSS SP-44 flanges - ISO 7005-1:1992 flanges are not identical to ASME B 16.5 and MSS SP 44 flanges but are deemed to comply with the dimensions specified in the ASME B 16.5 and MSS SP 44.

NOTE 2 - ISO 7005-2:1988 (cast iron) flanges PN 20, 50 are designed to be interchangeable with ANSI/ASME B16.1 (gray cast iron) and B 16.42 (ductile cast iron) but they are not identical. They are deemed to comply with dimensions specified in ASME B16.1 (gray cast iron) and B 16.42 (ductile cast iron).

NOTE 3 - ISO PN 2.5, 6 do not have a corresponding ASME class and ASME Class 75, 400 & 800 do not have corresponding ISO PN designation. The use of these PN and Class flange ratings are therefore not recommended.

Discussion Note 1: ISO 7005-1 (Steel) and 7005-2 (Cast Iron) are dimensional standards.

7005-1 does not mandate materials or corresponding Pressure / Temperature ratings, although various Informative Annexes list commonly used materials and corresponding Pressure / Temperature ratings. By including the Annexes D & E in 6.4.11 these annexes now become normative and part of this specification.

7005-2 includes as part of the standard, tables specifying materials and pressure temperature ratings and therefore these do not have to be added after the reference to 7005-2 in paragraph 6.4.11.

In contrast, the ASME flange standards include, as part of the specification, ASME materials and the corresponding pressure temperature limitations and therefore materials and pressure temperature references do not have to be added after ASME standards in paragraph 6.4.11.

Discussion Note 2: ISO 7005-1 and 7005-2 have flange rating (PN) divided into Series 1 and Series 2. Series 1 flanges are the basic ratings. Series 2 flanges are on a list for possible deletion. We have defaulted to Series 1 flanges therefore in 6.4.11.

Note to TF Chairmen: When equipment has cast flange nozzles the TF should confirm that the flange ratings for the material as outlined in these ISO and ASTM flange specifications are sufficient for the casing rating.

• 6.4.11.2 When ISO 7005-1:1992 has been specified, materials shall be in accordance with ISO 7005-1:1992 Annex D-1 (DIN) or Annex D-2 (ASTM) as specified. The Pressure Temperature ratings in Annex E shall correspond to the materials specified.

NOTE - ISO 7005-1:1992 Annex E Table 1-4 covers D-1 materials and Table 5-21 covers D-2 materials.

• 6.4.11.3 If specified, ASME B 16.47 Series A flanges shall be provided.

• 6.4.11.4 Cast, Ductile and Maluable iron flanges shall be flat faced and conform to the dimensional requirements of ISO 7005-2 or ASME B16.1 or l6.42 as specified. PN 20 (Class 125) flanges shall have a minimum thickness equal to PN50 (Class 250) for sizes DN 200 (8 NPS 8) and smaller.

5/6/2023

5/6/2023 Page 68 of 99

NOTE to TF Chairmen: If your standard addresses flange finishes note that ISO 7005-1 & 2 include flange finish requirements that are similar to, but not the same as, ASME B16.1, B 16.5, B16.42 or 16.47 You may wish to address this issue if flange finish has been a substantial enough issue to include in the present published standard.

• 6.4.11.5 Flanges other than those covered in ISO 7005-2:1988 shall conform to the dimensional requirements of the flanges specified in 6.4.11.1

Discussion: This requires machines which may be made of materials other than steel such as Ni resist or Bronze for example to have the flange dimensions equal to those of steel (ISO 7005-1). ISO 7005-2 covers nodular and ductile iron in addition to gray cast iron. The term Cast iron was not inclusive enough in 6.4.11.4 and therefore was removed and reference made to ISO 7005-2.

6.4.11.6 Flat face flanges with full raised face thickness are acceptable on casings (or cylinders) of all materials. Flanges in all materials that are thicker or have a larger outside diameter than required by ISO or ASME are acceptable. Non-standard (oversized) flanges shall be completely dimensioned on the arrangement drawing. If oversized flanges require studs or bolts of non-standard length, this requirement shall be identified on the arrangement drawing. [API 610]

6.4.11.7 Flanges shall be full faced or spot faced on the back and shall be designed for through bolting.

6.4.11.8 For all steel flanges, imperfections in the flange facing finish shall not exceed that permitted in ASME B 16.5 or ASME 16.47 as applicable.

• 6.4.12 Machined and studded connections shall conform to the facing and drilling requirements of ISO 7005-1:1992, 7005-2:1988, ASME B16.1, B16.5, B16.42 or B16.47 as specified. Studs and nuts shall be provided installed, the first 1.5 threads at both ends of each stud shall be removed.

Discussion: Threads are removed at the end of the stud to allow the stud to bottom without damaging the end threads in the hole. Threads are removed from both ends of the stud to allow either end of the stud to be inserted into the threaded hole.

6.4 13 Machined and studded connections and flanges not in accordance with ISO 7005-1:1992 ,7005-2:1988 or ASME B16.1, B16.5, B16.42 or B16.47 require purchaser's approval. Unless otherwise specified, the vendor shall supply mating flanges, studs and nuts for these nonstandard connections.

6.4.14 To minimize nozzle loading, and facilitate installation of piping, machine flanges shall be parallel to the plane shown of the flange as shown on the general arrangement drawing to

5/6/2023

5/6/2023 Page 69 of 99

within 0.5°. Studs or bolt holes shall straddle centerlines parallel to the main axes of the equipment.[API 674]

Discussion: The requirements for parallelism are not covered in other standards. The paragraph has been modified to allow the nozzle to be in any orientation, not just vertically or horizontally.

6.4.15 All of the purchasers connections shall be accessible for disassembly without requiring the machine, or any major part of the machine, to be moved.

6.4.16 The concentricity of the bolt circle and the bore of all casing flanges shall be such that the area of the machined gasket-seating surface is adequate to accommodate a complete standard gasket without protrusion of the gasket into the fluid flow. [API 617]

6.4.17 For socket-welded construction, there shall be a 1.5 mm (1/16 in) gap between the pipe end and bottom of the socket before welding. NOTE - See ASME B31.3 figure 328.5.2B (3) and 328.5.2C. [614]

6.4.18 Slip-on flanges are permitted only with the purchaser's specific approval.

6.4.19 MATERIAL INSPECTION OF PRESSURE-CONTAINING PARTS

NOTE - Refer to 8.2.2.1 for inspection of non pressure containing parts.

6.4.19.1 Regardless of the generalized limits presented in this section, it shall be the vendor's responsibility to review the design limits of all materials and welds in the event that more stringent requirements are specified. Defects that exceed the limits imposed in Section 6.4.17.1 shall be removed to meet the quality standards cited, as determined by additional magnetic particle or liquid penetrant inspection as applicable before repair welding. [API 617]

•6.4.19.2 If radiographic, ultrasonic, magnetic particle, or liquid penetrant inspection of welds or materials is required by the ASME Pressure Vessel Code or specified, the procedures and acceptance criteria in Table 13 shall apply, except as required by 6.4.17.4. [API 617]

5/6/2023

5/6/2023 Page 70 of 99

Table 13 — Materials inspection standards

Type of inspection Methods Acceptance criteria

For fabrications For castings

Radiography Section V, Articles 2 and 22 of the ASME

Code

Section VIII , Division 1, UW-51 (for 100 % radiography) and UW-

52 (for spot radiography) of the

ASME Code

Section VIII, Division 1, Appendix 7 of the

ASME Code

Ultrasonic inspection Section V, Articles 4, 5 and 23 of the ASME

Code

Section VIII, Division 1, UW53 and

Appendix 12, of the ASME Code

Section VIII, Division 1, Appendix 7, of the

ASME Code

Magnetic particle inspection

Section V, Articles 7 and 25 of the ASME

Code

Section VIII, Division 1, Appendix 6 of the

ASME Code

See acceptance criteria in 6.4.16.6 and table 2

Liquid penetrant inspection

Section V, Articles 6 and 24 of the ASME

Code

Section VIII, Division 1, Appendix 8 of the

ASME Code

Section VIII, Division 1, Appendix 7, of the

ASME Code

6.4.19.3 The purchaser shall be notified before making a major repair to a pressure containing part. Major repairs, for the purpose of purchaser notification only, is any defect that equals or exceeds any of the three criteria defined below.

1 The depth of the cavity prepared for repair welding exceeds 50% of the component wall thickness.2. The length of the cavity prepared for repair welding is longer than 150 mm (6 in) in any direction.3. The total area of all repairs to the part under repair exceeds 10% of the surface area of the part. (Modifications per 617 2.3.1.10.1)Note to TF Chairmen: The need for review of major repairs at the foundry level should be evaluated for the type of equipment involved. For commodity or standardized items that are stock (such as small end suction process pumps), manufacturer approved weld procedures are usually sufficient.

Major repairs typically occur at the foundry level in the manufacturing process. Purchaser's review of major repairs to components depends on the criticality of the part, the material and heat treatment and the extent of repair needed.

6.4.19.4 All repairs to pressure containg parts shall be made as required by the following documents:1) The repair of plates, prior to fabrication, shall be performed in accordance with the ASTM standard to which the plate was purchased.

5/6/2023

5/6/2023 Page 71 of 99

2) The repair of castings or forgings shall be performed prior to final machining in accordance with the ASTM standard to which the casting or forging was purchased.

3) The repair of a fabricated casing or the defect in either a weld or the base metal of a cast or fabricated casing, uncovered during preliminary or final machining, shall be performed in accordance with Table 13.

6.4.19.5 Plate used in fabrications shall be 100% Ultrasonic inspected prior to starting fabrication in accordance with the ASTM standard to which the plate was purchased.

Discussion: Typical specifications used for material in fabrication, for example ASTM A 516 do not specify default inspection of the base material plate. ASTM A 516 references ASTM A 220 which only calls for visual inspection of the plate edges and allows indications up to 1 inch in length. Additional inspection of the base material must be specified by the purchaser in supplemental requirements. For example ASTM A 516 Supplimental requirement S-8 requires UT inspection per ASTM A-435, S-11 per ASTM A-577 and S-12 ASTM A-578. All of these have asseptance criteria

Discussion: The inspection requirements of the ASME Pressure Vessel Code depend on the quality factor of a casting and joint efficiency of fabrication selected for the design or the material requirements.

Discussion: For UT inspection of fabrications, Section VIII, Division 1, UW-53 simply refers to  Appendix 12. Since UW 51 and 52 are referenced in the previous box concerning radiography, for consistency it was decided to leave in the reference to UW 53 .

6.4.19.6 Cast and Nodular iron may be inspected only in accordance with magnetic particle and liquid penetrant methods.

6.4.19.7 Spot radiography shall consist of a minimum of one 150-millimeter (6-inch) spot radiograph for each 7.6 meters (25 feet) of weld on each casing. As a minimum, one spot radiograph is required for each welding procedure and welder used for pressure-containing welds.

6.4.19.8 For magnetic particle inspections, linear indications shall be considered relevant only if the major dimension exceeds 1.6 millimeters (1/16 inch). Individual indications that are separated by less than 1.6 millimeters (1/16 inch) shall be considered continuous.

6.4.19.9 Cast steel magnetic casing parts shall be examined by magnetic particle methods. Acceptability of defects shall be based on a comparison with the photographs in ASTM E 125 Code. For each type of defect, the degree of severity shall not exceed the limits specified in Table 2.

Table 2 - Maximum Severity of Defects in Castings

5/6/2023

5/6/2023 Page 72 of 99

Type Defect DegreeI Linear discontinuities 1 (Code all)II Shrinkage 2III Inclusions 2 ( Code 3)IV Chills and chaplets 1V Porosity 1VI Welds 1

Discussion: The difference between this table and the ASME Code is that the code requires all linear discontinuities instead of degree 1 and degree 3 instead of degree 2 for inclusions.

6.5 EXTERNAL FORCES AND MOMENTS

Note to TF Chairmen: address forces and moments as required by the equipment being specified.

6.6 ROTATING ELEMENTS (OR GEAR ELEMENTS)

6.6.1 When vibration and/or axial-position probes are furnished, the rotor shaft sensing areas to be observed by the probes shall be concentric with the bearing journals. All sensing areas (both radial vibration and axial position) shall be free from stencil and scribe marks or any other surface discontinuity; such as an oil hole or a keyway, for a minimum of one probe-tip diameter on each side of the probe. These areas shall not be metallized, sleeved, or plated. The final surface finish shall be a maximum of 0,8 μm (32 μin) Ra, preferably obtained by honing or burnishing. These areas shall be properly demagnetized to the levels specified in API Standard 670 or otherwise treated so that the combined total electrical and mechanical runout does not exceed 6.35 μm [TI-617-0104] (0.25 mil [API 677] b. For areas to be observed by axial-position probes, 12.7 μm (0.5 mil).

NOTE - Refer to 6.8.7.9 and 6.8.7.10 for measurement and recording of mechanical and electrical runout. [API 677]

6.6.2 When it is specified that equipment shall have provisions for mounting vibration monitoring equipment in the future, the shaft shall be prepared in accordance with the requirements of API Standard 670.

6.6.3 Each rotor shall be clearly marked with a unique identification number. This number shall be on the non-drive end of the shaft or in another accessible area that is not prone to maintenance damage.Note to TF Chairmen: the location should be tailored to the equipment being specified.

6.6.4 Shafting shall be capable of transmitting torque at least equal to the rated torque of the coupling. For special purpose equipment, shaft end design shall conform to the requirements of API 671.

5/6/2023

5/6/2023 Page 73 of 99

Discussion: For general purpose equipment, the Task Force must decide on appropriate criteria for shaft end design. The following considerations should be evaluated: transients, off-design requirements (conditions) oversized drivers, and driver power vs. driven power.

API 671 states: “ 2.1.1.5 Unless otherwise specified, the coupling-to-shaft juncture, and the machinery shafting shall be capable of operating at a steady-state torque determined by Equation 1 using a service factor of 1.75 (see 2.1.1.9).

6.6.5 Shafts shall be machined from one-piece beat treated steel. Shafts with finished diameters 200 mm (8 in) and larger shall be forged. Shafts with finished diameters less than 200 mm(8 in) may be hot-rolled barstock purchased to the same quality and heat treatment criteria as shaft forgings.

Discussion: Hot-rolled barstock is generally suitable (at diameters less than 200 mm) for equipment with shrink-fit rotor components which do not have major changes in diameter requiring large amounts of metal removal. Rolled barstock can be thermally unstable, depending on how it is processed. It is generally acceptable where it is economically feasible utilizing forging quality and heat treatment criteria. Certain rotor combinations (such as for turbines and compressors) utilize a stub shaft design, and rolled barstock may not be practical.

6.6.6 All shaft keyways shall have fillet radii conforming to ASME B17.1.

Discussion: ISO 773 has been withdrawn by ISO and can not be referenced in a standard.CPC 5/13/03

Discussion: This requirement applies to all shaft keyways. not just those at the coupling(s).

6.6.7 Suggested from Phil Istre: Keys shall be the same material as the shaft.

6.6.8 Shaft shoulders against which rolling element bearings seat shall have filets conforming to ISO 582: 1995 . When inch series tapered roller bearings are used, the filets shall be in accordance with ABMA 19.2

NOTE - For the purpose of this provision ABMA 20 and 19.1 are equivalent to ISO 582:1995.

5/6/2023

5/6/2023 Page 74 of 99

Discussion: There is no ISO equivalent ABMA 19.2

6.7 SEALS

Note to TF Chairmen: address the subject of seals as required by the equipment being specified.

6.8 DYNAMICS

6.8.1 General

For a detailed discussion on rotor dynamics, refer to API Pub. 684 Tutorial on the API Standard Para-graphs Covering Rotor Dynamics and Balancing: An Introduction to Lateral Critical, Stability, and Train Torsional Analysis and Rotor Balancing.

NOTE 1 - Refer to Annex XXX for lateral analysis flow chart.

NOTE 2 - Refer to Annex XXX for torsional analysis flow chart.

6.8.1.1 In the design of rotor-bearing systems, consideration shall be given to all potential sources of periodic forcing phenomena (excitation) which shall include, but are not limited to, the following sources:

a. Unbalance in the rotor system.b. Oil-film instabilities (whirl).c. Internal rubs.d. Blade, vane, nozzle .and diffuser passing frequencies.e. Gear-tooth meshing and side bands.f. Coupling misalignment.g. Loose rotor-system components.h. Hysteretic and friction whirl.i. Boundary-layer flow separation.j. Acoustic and aerodynamic cross-coupling forces.k. Asynchronous whirl.l. Ball. and race frequencies of rolling element bearings.m. Electrical line frequency.

NOTE 1- The frequency of a potential source of excitation may be less than, equal to, or greater than the rotational speed of the rotor.

NOTE 2 - When the frequency of a periodic forcing phenomenon (excitation) applied to a rotor-bearing support system coincides with a natural frequency of that system, the system will be in a state of resonance. A rotor-bearing support system in resonance may have the magnitude of its normal vibration amplified. The magnitude of amplification and, in the case of critical speeds, the rate of change of the phase-angle with respect to speed, is related to the amount of damping in the system.

5/6/2023

5/6/2023 Page 75 of 99

6.8.1.2 For the purposes of this standard, resonant conditions of concern are those with an amplification factor (AF) equal to or greater than 2.5 (see Figure SP-6).

6.8.1.3 Resonances of structural support systems that are within the vendor's scope of supply and that affect the rotor vibration amplitude shall not occur within the specified operating speed range or the specified separation margins (SM) (see SP 6.8.2.10). The effective stiffness of the structural support shall be considered in the analysis of the dynamics of the rotor-bearing-support system (see SP 6.8.2.4d).

6.8.1 .4 The vendor who is specified to have unit responsibility for the complete drive train shall communicate the existence of any undesirable running speeds in the range from zero to trip speed. A list of all undesirable speeds from zero to trip shall be submitted to the purchaser for its review and included in the instruction manual (see Annex B of the applicable chapter).

5/6/2023

5/6/2023 Page 76 of 99

NOTE - Examples of undesirable speeds are those caused by the rotor lateral critical speeds, system torsionals, and blading modes.

6.8.2 Lateral Analysis

6.8.2.1 Critical speeds and their associated AFs shall be determined by means of a damped unbalanced rotor response analysis.

6.8.2.2 The location of all critical speeds below the trip speed shall be confirmed on the test stand during the mechanical running test (see 6.8.3.1). The accuracy of the analytical model shall be demonstrated (see 6.8.3).

6.8.2.3 Prior to carrying out the damped unbalanced response analysis, the vendor shall conduct an undamped analysis to identify the undamped critical speeds and deter-mine their mode shapes located in the range from 0% -125% of trip speed. Unless otherwise specified, the results of the undamped analysis shall be furnished. The presentation of the results shall include:

a. Mode shape plots (relative amplitude vs. axial position on the rotor).b. Critical speed-support stiffness map (frequency vs. sup-port stiffness). Superimposed on

this map shall be the calculated system support stiffness, horizontal (kx). and vertical (ky) (see Figure SP-7).

NOTE - For machinery with widely varying bearing loads and/or load direction such as overhung style machines, the vendor can propose to substitute mode shape plots for the undamped critical speed map and list the undamped critical speed for each of the identified modes.

5/6/2023

5/6/2023 Page 77 of 99

6.8.2.4 The damped unbalanced response analysis shall include but shall not be limited to the following:

NOTE 1 - The following is a list of items the analyst is to consider. It does not address the details and product of the analysis which is covered in 6.8.2.7 and 6.8.2.8.

a. Rotor masses, including the mass moment of coupling halves, stiffness, and damping effects (for example, accumulated fit tolerances, fluid stiffening and damping).

b. Bearing lubricant-film stiffness and damping values including changes due to speed, load, preload, range of oil temperatures, maximum to minimum clearances resulting from accumulated assembly tolerances, and the effect of asymmetrical loading which may be caused by gear forces, side streams, eccentric clearances, etc.

c. For tilt-pad bearings, the pad pivot stiffness.d. Support stiffness, mass, and damping characteristics, including effects of frequency dependent variation.

The term “support” includes the foundation or support structure, the base, the machine frame and the bearing housing as appropriate. For machines whose bearing support system stiffness values are less than or equal to 3.5 times the bearing oil film stiffness values, support stiffness values derived from modal testing or calculated frequency dependent support stiffness and damping values (impedances) shall be used. The vendor shall state the support stiffness values used in the analysis and the basis for these values (for example, modal tests of similar rotor support systems, or calculated support stiffness values).

NOTE 2 - The support stiffness should in most cases be no more than 8.75 x 108 N/m (5 x 106 lb/in).

NOTE 3 - Guidelines are used to define whether or not bearing support stiffness should be considered. While modal testing of the actual bearing support system would be preferred, an analytical analysis (such as FEA) is permitted.

e. Rotational speed, including the various starting-speed detents, operating speed and load ranges (including agreed upon test conditions if different from those specified), trip speed, and coast-down conditions.

f. The influence, over the operating range, of the hydrodynamic stiffness and damping generated by the casing shaft end seals.

g. The location and orientation of the radial vibration probes which shall be the same in the analysis as in the machine.

h. Squeeze film dampers.

6.8.2.5 In addition to the damped unbalanced response analysis requirements of 6.8.2.4, for machines equipped with rolling element bearings, the vendor shall state the bearing stiffness and damping values used for the analysis and either the basis for these values or the assumptions made in calculating the values.

6.8.2.6 When specified, the effects of other equipment in the train shall be included in the damped unbalanced response analysis (that is, a train lateral analysis shall be performed).

NOTE - In particular, this analysis should be considered for machinery trains with rigid couplings.

5/6/2023

5/6/2023 Page 78 of 99

6.8.2.7 A separate damped unbalanced response analysis shall be conducted for each critical speed within the speed range of 0% - 125% of trip speed. Unbalance shall analytically be placed at the locations that have been determined by the undamped analysis to affect the particular mode most adversely. A separate unbalanced analysis shall be performed for the placement of each unbalance. For the translatory (symmetric) modes, the unbalance shall be based on the sum of the journal static loads and shall be applied at the location of maximum displacement. For conical (asymmetric) modes, an unbalance shall be added at the location of maximum displacement nearest to each journal bearing. These unbalances shall be 180 degrees out of phase and of a magnitude based on the static load on the adjacent bearing. Figure SP-8 shows the typical mode shapes and indicates the location and definition of U for each of the shapes. The magnitude of the unbalances shall be 4 times the value of U as calculated by Equations 2a or 2b.

In SI units:

U = 6 350 W/N (2a)

or .254 m mass displacement, whichever is greater.

In U.S. Customary units:

U = 4 W/N (2b)

or 10 µ in mass displacement, whichever is greater.

where

U = input unbalance for the rotordynamic response analysis in g-mm (oz-in),N = maximum continuous operating speed, r/minW = journal static load in kg (lbm), or for bending modes where the maximum

deflection occurs at the shaft ends, the overhung mass (that is the mass of the rotor outboard of the bearing) in kg (lbm) (see Figure SP-8).

NOTE - The limits on mass displacement are in general agreement with the capabilities of conventional balance machines, and are necessary to invoke for small rotors running at speeds above 25,000 r/min. [ 616]

5/6/2023

5/6/2023 Page 79 of 99

6.8.2.7.1 For rotors where the impellers are cantilevered beyond the journal bearings, unbalance shall be added at the impellers and components such as locknuts, shaft end seals and the coupling for the case of the non-integrally geared rotors. Each mode that is less than 125% of trip speed shall be analyzed. The modes shall be calculated at minimum and maximum support stiffness and in the case of integrally geared rotors include the change in support stiffness resulting from minimum to maximum torque transmitted through the gearing. The unbalance shall be located at or close to the component center of gravity and phased to create maximum synchronous response amplitude.

6.8.2.7.2 For rotors which are between bearing designs, unbalance shall be added at the impellers and major rotor components such as balance drums and couplings. The unbalance shall be located at or close to the component center of gravity and phased to create maximum synchronous response amplitude.

6.8.2.8 As a minimum, the unbalanced response analysis shall produce the following:

NOTE - The following is the list of analysis details and identifies the deliverables. The items to be considered in the analysis were identified in 6.8.2.4.

a. Identification of the frequency of each critical speed ,regardless of amplification factor, in the range from 0% - 125% of the trip speed.

b. Frequency, phase and response amplitude data (Bode plots) at the vibration probe locations through the range of each critical speed resulting from the unbalance specified in 6.8.2.7.

c. The plot of deflected rotor shape for each critical speed resulting from the unbalances specified in 6.8.2.7, showing the major-axis amplitude at each coupling plane of flexure, the centerlines of each bearing, the locations of each radial probe, and at each seal throughout the machine as appropriate. The minimum design diametral running clearance of the seals shall also be indicated.

d. Additional Bode plots that compare absolute shaft motion with shaft motion relative to the bearing housing for machines where the support stiffness is less than 3.5 times the oil-film stiffness.

6.8.2.9 Additional analyses shall be made for use with the verification test specified in 6.8.3. The location of the unbalance shall be determined by the vendor. Any test stand parameters which influence the results of the analysis shall be included.

NOTE - For most machines, there will only be one plane readily accessible for the placement of an unbalance; for example, the coupling flange on a single ended drive machine, or the impeller hub or disk on an integrally geared machine, or expander-compressors. However, there is the possibility that more planes are available such as axial compressor or field balance planes, or on through - drive compressors. When this occurs, and there is the possibility of exciting other criticals. Multiple runs may be required when more than one plane is available.

5/6/2023

5/6/2023 Page 80 of 99

6.8.2.10 The damped unbalanced response analysis shall indicate that the machine will meet the following SM:

a. If the AF at a particular critical speed is less than 2.5, the response is considered critically damped and no SM is required.

b. If the AF at a particular critical speed is equal to 2.5 or greater and that critical speed is below the minimum speed, the SM (as a percentage of the minimum speed) shall not be less than the value from Equation SP-A3 or the value of 16 which ever is less.

(3)

c. If the AF at a particular critical speed is equal to 2.5 or greater and that critical speed is above the maximum continuous speed, the SM (as a percentage of the maximum continuous speed) shall not be less than the value from Equation 4 or the value of 26 whichever is less.

(4)

6.8.2.11 The calculated unbalanced peak-to-peak amplitudes (see 6.8.2.8b) shall be multiplied using the correction factor calculated from Equation 5. The correction factor shall have a value greater than 0.5.

(5)

where

CF = correction factor,A1 = amplitude limit, calculated using Equations 6a or 6b in m (mils) peak to peak,A4X = peak-to-peak amplitude at the probe location per requirements of 6.8.2.8, item b, in m (mils) peak. to peak.

In SI units:

(6a)

In Customary units:

(6b)

5/6/2023

5/6/2023 Page 81 of 99

where

N = maximum continuous operating speed, in r/min.

6.8.2.12 The calculated major-axis, peak-to-peak, unbalanced rotor response amplitudes, corrected in accordance with 6.8.2.11 at any speed from zero to trip speed shall not exceed 75% of the minimum design diametral running clearances throughout the machine (with the exception of floating-ring seal locations). For machines with abraidable seals, the response amplitude to the running clearance shall be mutually agreed.

NOTE - Running clearances may be different than the assembled clearances with the machine shutdown.

6.8.2.13 If the analysis indicates that the SMs still can-not be met or that a non-critically damped response peak falls within the operating speed range and the purchaser and vendor have agreed that all practical design efforts have been exhausted, then acceptable amplitudes shall be mutually agreed upon by the purchaser and the vendor, subject to the requirements of 6.8.3.3.

• 6.8.2.14 When specified, in addition to the other requirements of 6.8.2, the lateral analysis report shall include the following:

a. Dimensional data of the bearing design in sufficient detail to enable calculations of stiffness and damping coefficients.

b. Shaft geometry with sufficient detail to model the shaft including the location of bearing centerlines and mounted components.

c. The weight, polar and transverse moments of inertia and center of gravity of the impellers, balance piston, shaft end seals and coupling(s) with sufficient detail to conduct an inde-pendent analysis of the rotor.

d. The input mass elastic model used for the vendors analysis.[616]e. The support stiffness used in the analysis and its basis.

6.8.3 Unbalanced Rotor Response Verification Test

6.8.3.1 An unbalanced rotor response test shall be per-formed as part of the mechanical running test (Note: See Section of the applicable chapter), and the results shall he used to verify the analytical model. The actual response of the rotor on the test stand to the same arrangement of unbalance and bearing loads as was used in the analysis specified in 6.8.2.9 shall be the criterion for determining the validity of the damped unbalanced response analysis. To accomplish this, the requirements of 6.8.3.1.1 through 6.8.3.I.6 shall be followed.

6.8.3.1.1 During the mechanical running test (Note: See Section of the applicable chapter), the amplitudes and phase angle of the shaft vibration from zero to trip speed shall be recorded. Eliminated: analog equipment no longer used. Digital instrumentation now used.

NOTE - This set of readings is normally taken during a coastdown, with convenient increments of speed such as 50 r/min. Since at this point the rotor is balanced, any vibration amplitude and phase detected should be the result of residual unbalance and mechanical and electrical runout.

5/6/2023

5/6/2023 Page 82 of 99

6.8.3.1.2 The location of critical speeds below the trip speed shall be established.

6.8.3.1.3 The unbalance which was used in the analysis performed in 6.8.2.9, shall be added to the rotor in the location used in the analysis. The unbalance shall not exceed 8 times the value from Equations 2a or 2b.

6.8.3.1.4 The machine shall then be brought up to the trip speed and the indicated vibration amplitudes and phase shall be recorded using the same procedure used for 6.8.3.1.1.

6.8.3.1.5 The corresponding indicated vibration data taken in accordance with 6.8.3.1.1 shall be vectorially subtracted from the results of this test.

NOTE - It is practical to store the residual unbalance vibration measurements recorded in the step at 6.8.3.1.1 and by use of computer code perform the vectorial subtraction called for in this paragraph at each appropriate speed. This makes the comparison of the test results with the computer analysis of 6.8.2.9 quite practical. It is necessary for probe orientation be the same for the analysis and the machine for the vectorial subtraction to be valid.

6.8.3.1.6 The results of the mechanical run test including the unbalance response verification test shall be compared with those from the analytical model specified at 6.8.2.9.

6.8.3.2 The vendor shall correct the model if it fails to meet either of the following criteria:

a. The actual critical speeds determined on test deviate from the corresponding critical speeds predicted by analysis by more than 5%. Where the analysis predicts more than one critical speed in a particular mode (due, for example, to the bearing characteristics being significantly different horizontally and vertically or between the two ends of the machine), the test value shall not be lower than 5% below the lowest predicted value nor higher than 5% above the highest predicted value.

NOTE - It is possible, that the vertical and horizontal stiffnesses are significantly different and the analysis will predict two differing critical speeds. Should the operating speed fall between these critical speeds, these two critical speeds should be treated separately, as if they resulted from separate modes.

b. The actual major axis amplitude of peak responses from test, including those critically damped, exceeds the predicted values. The predicted peak response amplitude range shall be determined from the computer model based on the four radial probe locations.

6.8.3.3 If the support stiffness is less than 2 times the bearing oil film stiffness, the absolute vibration of the bearing housing shall be measured and vectorially added to the relative shaft vibration, in both the balanced (see 6.8.3.1.1) and in the unbalanced (see 6.8.3.1.3) condition before proceeding with the step specified in 6.83.1.6. In such a case, the measured response shall be compared with the predicted absolute shaft movement.

5/6/2023

5/6/2023 Page 83 of 99

6.8.3.4 Unless otherwise specified, the verification test of the rotor unbalance shall be performed only on the first rotor tested, if multiple identical rotors are purchased.

6.8.3.5 The vibration amplitudes and phase from each pair of x-y vibration probes shall be vectorially summed at each vibration response peak after correcting the model, if required, to determine the maximum amplitude of vibration. The major-axis amplitudes of each response peak shall not exceed the limits specified in 6.8.2.12. R Brown to reword.

And possibly ??? include criteria for amount of unbalance and acceptable vibration.

6.8.4 Additional Testing

6.8.4.1 Additional testing is required ( see 6.8.4.2) if from the shop verification test data (see 6.8.3) or from the damped, corrected unbalanced response analysis (see 6.8.3.3), it appears that either of the following conditions exists:

a. Any critical response which fails to meet the SM requirements (see 6.8.2.10) or which falls within the operating speed range.

b. The clearance requirements of 6.8.2.12 have not been met.

NOTE - When the analysis or test data does not meet the requirements of the standard, additional more stringent testing is required. The purpose of this additional testing is to determine on the test stand that the machine will operate successfully.

6.8.4.2 Unbalance weights shall be placed as described in 6.8.2.7; this may require disassembly of the machine. Unbalance magnitudes shall be achieved by adjusting the indicated unbalance that exists in the rotor from the initial run to raise the displacement of the rotor at the probe locations to the vibration limit defined by Equations 6a or 6b (see 6.8.2.11) at the maximum continuous speed; however, the unbalance used shall be no less than twice or greater than 8 times the unbalance limit specified in 6.8.2.7, Equations 2a or 2b. The measurements from this test, taken in accordance with 6.8.3.1.1 and 6.8.3.1.2, shall meet the following criteria:

a. At no speed outside the operating speed range, including the SM, shall the shaft deflections exceed 90% of the mini-mum design running clearances.

b. At no speed within the operating speed range, including the SM, shall the shaft deflections exceed 55% 'of the mini-mum design running clearances or 150% of the allowable vibration limit at the probes (see SP6.8.2.11).

6.8.4.3 The internal deflection limits specified in 6.8.4.2 items a and b shall be based on the calculated displacement ratios between the probe locations and the areas of concern identified in 6.8.2.12 based on a corrected model, if required. Actual internal displacements for these tests shall be calculated by multiplying these ratios by the peak readings from the probes. Acceptance will be based on these calculated displacements or inspection of the seals if the machine is

5/6/2023

5/6/2023 Page 84 of 99

opened. Damage to any portion of the machine as a result of this testing shall constitute failure of the test. Minor internal seal rubs that do not cause clearance changes outside the vendor's new-part tolerance do not constitute damage.

6.8.5 Level 1 Stability Analysis

6.8.5.1 A stability analysis shall be performed on all rotors except those whose maximum continuous speed is below the first critical speed in accordance with 6.8.2.3, as calculated on rigid supports. For this analysis, the machine inlet and discharge conditions shall be at either the rated condition or another operating point unless the vendor and purchaser agree upon another operating point.[616]

NOTE - Level I analysis was developed to fulfill two purposes: first, it provides an initial screening to identify rotors that do not require a more detailed study. The approach as developed is conservative and not intended as an indication of an unstable rotor. Second. the Level I analysis specifies a standardized procedure applied to all manufacturers similar to that found in 6.8.2. (Refer to 3.12 for a detailed explanation.)

6.8.5.2 The model used in the Level I analysis shall include the items listed in 6.8.2.4 together with the effects of squeeze film dampers where used.

6.8.5.3 All components shall be analyzed using the mean values of oil inlet temperature and the extremes of the operating limits for clearance to produce the minimum log decrement.

6.8.5.4 When tilt pad journal hearings are used, the analysis shall be performed with synchronous tilt pad coefficients.

6.8.5.5 For rotors that have quantifiable external radial loading (e.g., integrally geared compressors), the stability analysis shall also include the external loads associated with the operating conditions defined in 6.8.5.1. For some rotors, the unloaded (or minimal load condition) may represent the worst stability case and should be considered.

6.8.5.6 The anticipated cross coupling, QA, present in the rotor is defined by the following procedures:

a. For centrifugal compressors:

The parameters in Equation 7 shall be determined based on the specified operating condition in SP6.8.5.1.

(7)

Equation 7 is calculated for each impeller of the rotor. QA is equal to the sum of qA for all impellers.

b. For axial flow rotors:

5/6/2023

(8)

5/6/2023 Page 85 of 99

(8)

Equation 8 is calculated for each stage of the rotor. QA is equal to the sum of qA for all stages.

6.8.5.7 An analysis shall be performed with a varying amount of cross coupling introduced at the rotor mid-span for between bearing rotors or at the center of gravity of the stage or impeller for single overhung rotors. For double overhung rotors, the cross coupling shall be placed at each stage or impeller concurrently and should reflect the ratio of the anticipated cross coupling, (IA, calculated for each impeller or stage.

6.8.5.8 The applied cross coupling shall extend from zero to the minimum of:

a. A level equal to 10 times the anticipated cross coupling, QA.b. The amount of the applied cross coupling required to pro-duce a zero log decrement, Q0.

This value can be reached by extrapolation or linear interpolation between two adjacent points on the curve.

6.8.5.9 A plot of the calculated log decrement, 8, for the first forward mode shall be prepared for the minimum and maximum component clearances. Each curve shall contain a minimum of five calculated stability points. The ordinate (y axis) shall be the log decrement. The abscissa (x-axis) shall be the applied cross coupling with the range defined in 6.8.5.8. For double overhung rotors, the applied cross coupling will be the sum of the cross coupling applied to each impeller or stage.

A typical plot is presented in Figure SP-9. Q0 and QA are identified as the minimum values from either component clearance curves.

6.8.5.1 0 Level I Screening Criteria:

a. For centrifugal compressors:

If any of the following criteria apply, a Level II stability analysis shall be performed:

i. Q0 / QA < 2.0.ii. A < 0.1.iii. 2.0 < Q0 / QA < 10 and CSR is contained in Region B of Figure SP-l0.

Otherwise, the stability is acceptable and no further analyses are required.

b. For axial flow rotors:

If A < 0.1, a Level II stability analysis shall be performed. Otherwise, the stability is acceptable

and no further analyses are required.

5/6/2023

5/6/2023 Page 86 of 99

5/6/2023

5/6/2023 Page 87 of 99

6.8.6 Level II Stability Analysis

6.8.6.1 A Level II analysis, which reflects the actual operating behavior of the rotor, shall be performed as required by 6.8.5.10.

6.8.6.2 The Level II analysis shall include the dynamic effects from all sources that contribute to the overall stability of the rotating assembly as appropriate. These dynamic effects shall replace the anticipated cross coupling, QA. These sources may include, but are not limited to, the following:

a. Labyrinth seals.b. Balance piston.c. Impeller/blade flow.d. Shrink fits.e. Shaft material hysteresis.

It is recognized that methods may not be available at present to accurately model the destabilizing effects from all sources listed above. The vendor shall state how the sources are handled in the analysis.

6.8.6.3 The Level II analysis shall be calculated for the operating conditions defined in 6.8.5.1 extrapolated to maximum continuous speed. The modeling requirements of 6.8.5.2, 6.8.5.4 and 6.8.5.5 shall also apply. The component dynamic characteristics shall be calculated at the extremes of the allowable operating limits of clearance and oil inlet temperature to produce the minimum log decrement.

6.8.6.4 The frequency and log decrement of the first forward damped mode shall be calculated for the following conditions (except for double overhung machines where the first two forward modes shall be considered):

a. Rotor and support system only (basic log decrement, 60.b. For the addition of each group of destabilizing effects utilized in the analysis.c. Complete model including all destabilizing forces (final log decrement, 8f).

6.8.6.5 Acceptance Criteria

The Level II stability analysis shall indicate that the machine, as calculated in 6.8.6.1 through 6.8.6.3, shall have a final log decrement, f, greater than 0.1.

6.8.6.6 If after all practical design efforts have been exhausted to achieve the requirements of 6.8.6.5, accept-able levels of the log decrement, f, shall be mutually agreed upon by the purchaser and vendor.

5/6/2023

5/6/2023 Page 88 of 99

NOTE - This stability analysis section represents the first uniform methodology specified for centrifugal compressors, steam turbines and axial and/or radial flow rotors. The analysis method and the acceptance criteria specified are unique in that no manufacturer has used these exact methods to evaluate the susceptibility of their equipment to subsynchronous instability. When these requirements are included within a specification, all manufacturers are expected to analyze their rotors accordingly. However, it should be recognized that other analysis methods and continuously updated acceptance criteria have been used successfully since the mid-1970s to evaluate rotordynamic stability. The historical data accumulated by machinery manufacturers for successfully operated machines may conflict with the acceptance criteria of this specification. If such a conflict exists and a vendor can demonstrate that his stability analysis methods and acceptance criteria predict a stable rotor, then the vendor's criteria should be the guiding principle in the determination of acceptability.

Symbols

Bc = 3,

Bt = 1.5,

C = 9.55 (63),

DC = Impeller diameter, mm (in).

Dt = Blade pitch diameter, mm (in),

HC = Minimum of diffuser or impeller discharge width per impeller, mm (in),

Ht = Effective blade height, mm (in),

HP = Rated power per stage or impeller, Nm/sec. (HP),

CSR = Critical speed ratio is defined as:

CSR = maximum continuous speed first undamped critical speed on rigid support (FCSR)

N = Operating speed, r/min.,

QA = Anticipated cross coupling for the rotor, KNI mm (Klbf/in) defined as:

Q0 = Minimum cross coupling needed to achieve a log decrement equal to zero for either minimum or maximum component clearance,

qA = Cross coupling defined in Equation 7 or 8 for each stage or impeller, KN/mm (Klbf/in),

5/6/2023

5/6/2023 Page 89 of 99

S = Number of stages or impellers,

A = Minimum log decrement at the anticipated cross coupling for either minimum or maxi-mum component clearance,

b = Basic log decrement of the rotor and support system only,

f = Log decrement of the complete rotor support system from the Level II analysis,

d = Discharge gas density per stage or impeller,

Ps = Suction gas density per stage or impeller,

pave = Average gas density across the rotor, kg/m3 (lb/ft3).

Definitions

Stability analysis is the determination of the natural frequencies and the corresponding logarithmic the damped rotor/support system using a complex eigenvalue analysis.

Synchronous tilt pad coefficients are derived from the complex frequency dependent coefficients with the frequency equal to the rotational speed of the shaft.

Stage refers to an individual turbine or axial compressor blade row.

Hysteresis or internal friction damping causes a phase difference between the stress and strain in any material under cyclic loading. This phase difference produces the characteristic hysteric loop on a stress-strain diagram and thus, a destabilizing damping force.

Minimum clearance for a tilt pad bearing occurs at the maximum preload condition. These can be calculated using the following formulas:

For minimum clearance at maximum preload:

For maximum clearance at minimum preload:

5/6/2023

5/6/2023 Page 90 of 99

6.8.7 Torsional Analysis

6.8.7.1 For motor-driven units and units including gears, units comprising three or more coupled machines (excluding any gears), or when specified, the vendor having unit responsibility shall ensure that a torsional vibration analysis of the complete coupled train is carried out and shall be responsible for directing any modifications necessary to meet the requirements of 6.8.7.2 through 6.8.7.6.

6.8.7.2 Excitation of torsional natural frequencies may come from many sources which may or may not be a function of running speed and should be considered in the analysis. These sources shall include but are not limited to the following:

a. Gear characteristics such as unbalance, pitch line runout, and cumulative pitch error.b. Cyclic process impulses.c. Torsional transients such as start-up of synchronous electric motors and generator phase-

to-phase or phase-to-ground faults.d. Torsional excitation resulting from electric motors, reciprocating engines, and rotary type

positive displacement machines.e. Control loop resonance from hydraulic, electronic governors, and variable frequency

drives.f. One and 2 times line frequency.g. Running speed or speeds.h. Harmonic frequencies from variable frequency drives.

6.8.7.3 The torsional natural frequencies of the complete train shall be at least 10% above or 10% below any possible excitation frequency within the specified operating speed range (from minimum to maximum continuous speed).

6.8.7.4 Torsional natural. frequencies at two or more times running speeds shall preferably be avoided or, in systems in which corresponding excitation frequencies occur, shall be shown to have no adverse effect.

6.8.7.5 When torsional resonances are calculated to fall within the margin specified in 6.8.7.3 (and the purchaser and the vendor have agreed that all efforts to remove the critical from within the limiting frequency range have been exhausted), a stress analysis shall be performed to demonstrate that the resonances have no adverse effect on the complete train. The assumptions made in this analysis regarding the magnitude of excitation and the degree of damping shall be clearly stated. The acceptance criteria for this analysis shall be mutually agreed upon by the purchaser and the vendor.

6.8.7.6 In addition to the torsional analyses required in 6.8.7.2 through 6.8.7.5, the vendor shall

5/6/2023

5/6/2023 Page 91 of 99

perform a transient torsional vibration analysis for synchronous motor driven units, using a time-transient analysis. The requirements of 6.8.7.6.1 through 6.8.7.6.4 shall be followed. (include transient for short circuit analysis for inductioin and synchronous) (616)

6.8.7.6.1 In addition to the parameters used to perform the torsional analysis specified in 6.8.7.1, the following shall. be included:

a. Motor average torque, as well as pulsating torque (direct and quadrature axis) vs. speed or time characteristics. (added time for short circuit analysis)

b. Load torque vs. speed characteristics.

Electrical system characteristics effecting the motor terminal voltage or the assumptions made concerning the terminal voltage including the method of starting, such as across the line, or some method of reduced voltage starting.

6.8.7.6.2 The analysis shall generate the maximum torque as well as a torque vs. time history for each of the shafts in the machinery train. The maximum torques shall be used to evaluate the peak torque capability of coupling components, gearing and interference fits of components such as coupling hubs. The torque vs. time history shall be used to develop a cumulative damage fatigue analysis of shafting, keys and coupling components.

6.8.7.6.3 Appropriate fatigue properties and stress concentrations shall be used.

6.8.7.6.4 An appropriate cumulative fatigue algorithm shall be used to develop a value for the safe number of starts. The safe number of starts shall be as mutually agreed by the purchaser and vendor.

NOTE - Values used depend on the analytical model used and the vendor's experience. Values of 1 000 – 1 500 starts are common. API Std 541 requires 5 000 starts. This is a reasonable assumption for a motor since it does not add significant cost to the design. The driven equipment, however, would be designed with overkill to meet this requirement. Example: 20-year life, 1 start/week = 1040 starts. Equipment of this type normally would start once every few years rather than once per week. A reasonable number of starts should therefore be specified.

6.8.8 Vibration and Balancing

6.8.8.1 Major parts of the rotating element, such as the shaft, balancing drum and impellers, shall be individually dynamically balanced before assembly, to ISO 1940-1 Grade G1 or better. When a bare shaft with a single keyway is dynamically balanced, the keyway shall be filled with a fully crowned half key, in accordance with ISO 8821. Keyways 180 degrees apart, but not in the same transverse plane, shall also be filled. The initial balance correction to the bare shaft shall be recorded. The components to be mounted on the shaft (impellers, balance drum, etc.), shall also be balanced in accordance with the "half-key-convention," as described in ISO 8821.

6.8.8.2 Unless otherwise specified, the rotating element shall be sequentially multiplane dynamically balanced during assembly. This shall be accomplished after the addition of no more than two major components. Balancing correction shall only be applied to the elements added.

5/6/2023

5/6/2023 Page 92 of 99

Minor correction of other components may be required during the final trim balancing of the completely assembled element. In the sequential balancing process, any half keys used in the balancing of the bare shaft (see 6.8.8.1) shall continue to be used until they are replaced with the final key and mating element. On rotors with single keyways, the keyway shall be filled with a fully crowned half-key. The weight of all half-keys used during final balancing of the assembled element shall be recorded on the residual unbalance worksheet (see Annex B). The maximum allowable residual unbalance per plane (journal) shall be calculated as follows:

In SI units:

Umax = 6 350W/N (9a)

or 0,254 m of mass eccentricity, whichever is greater.

In U.S. Customary units:

Umax = 4W/N (9b)

or 10 mils of mass eccentricity, whichever is greater.

where

Umax = residual unbalance, g-mm (oz-in),W = journal static weight load, kilograms (lb), N = maximum continuous speed, r/min. Mass eccentricity = Unbalance/Weight = [U/1 000W (U/16W)].

6.8.8.2.1 When the vendors standard assembly procedures require the rotating element to be disassembled after final balance to allow compressor assembly (i.e., stacked rotors with solid diaphragms and compressor/expanders), the vendor shall, as a minimum, perform the following operations:

a. To ensure the rotor has been assembled concentrically, the vendor shall take runout readings on the tip of each element (impeller or disc). The runout on any element shall not exceed a value agreed upon between the purchaser and the vendor.

b. The vendor shall balance the rotor to the limits of 6.8.8.2, Equations 9a or 9b.c. The vendor shall provide historic unbalance data readings of the change in balance due to

disassembly and reassembly. This change in unbalance shall not exceed 4 times the sensi-tivity of the balance machine. For this purpose, balance machine sensitivity is 254 pi (10 mils) maximum.

d. The vendor shall conduct an analysis in accordance with 6.8.2, to predict the vibration level during testing, using an unbalance equal to that in item b, plus 2 times the average change in balance due to disassembly and reassembly as defined in item c. The results of this analysis shall show that the predicted vibration at design speed on test shall be no greater than 2 times the requirements of 6.8.8.8.

5/6/2023

5/6/2023 Page 93 of 99

e. After the rotor has been reassembled in the compressor case, the vibration during testing shall meet the limits as shown in 6.8.8.8.

NOTE - Trim balancing in the compressor case may be done to achieve this level.

6.8.8.2.1.1 When specified, the vendor shall record the balance readings after initial balance for the contract rotor. The rotor shall then be disassembled and reassembled. The rotor shall be check balanced after reassembly to determine the change in balance due to disassembly and reassembly. This change in balance shall not exceed that defined in 6.8.8.2.1 c.

•6.8.8.3 When specified, completely assembled rotating elements shall be subject to operating-speed (at speed) balancing in lieu of a sequential low speed balancing (see 6.8.8.2). When the vendor's standard balance method is by operating-speed balancing in lieu of a sequential low speed balancing and operating speed balancing is not specified, it may be used with the purchaser's approval. The operating-speed balance shall be in accordance with 6.8.8.4.

6.8.8.4 Operating Speed Balancing Procedure

6.8.8.4.1 The following information shall be provided, prior to high speed balancing:a) The contract rotor dynamics analysis. This analysis will provide information about the predicted rotor mode shape as it passes through its resonant frequencies and about the best location for balance weights to minimize rotor vibration. b. Latest low speed balance records.c. Mechanical radial and axial runout checks of the rotor.d. If applicable, transfer tapes showing contact-hydraulic fit coupling hub/shaft end.e. Bearing / shaft clearance.

6.8.8.4.2 Job bearings or bearings identical to job bearings, shall be used.

NOTE - Evacuated tilting pad bearing ( bearings with out end seals) may need temporary end seals with twice bearing clearance. Even though the inlet oil is introduced to the housing at around 20 psig, the housing cannot maintain a positive pressure and the oil immediately atomizes, resulting in oil starvation. This manifests itself as a subsynchronous rotor vibration.

Discussion: in the evacuated tilting pad bearing design, in order to reduce the bearing temperatures, the end seals which retain the oil in the pad section of the bearings have been removed. This allows the hot oil to exit the pad cavity.

In 1991, Tanaka [1] introduced the concept of removing the end seals from tilting pad journalbearings. He found that evacuating the bearing housing cavity produced significantly lower pad

5/6/2023

5/6/2023 Page 94 of 99

operating temperatures compared to the conventional flooded housing designs. This concept has been developed further by Nicholas [2] with the introduction of spray bars and wide open housing drains as illustrated in Figure 3-13.While the Figure 3-13 design has been successful in reducing pad operating temperatures from10-15% [2], care must be taken when implementing the design. The wide open end seals and housing drains result in low housing cavity pressures, often below 1.0 psig. Conversely,conventional flooded housing designs have typical housing pressures that range from 5-15 psig for a 20 psig oil inlet. These low housing pressures can lead to oil starvation and subsynchronous vibration if improperly applied.

Figure 3-13 illustrates one misapplication example. Open end seals and open housing drainswill not work in a high speed balance vacuum. Even though the inlet oil is introduced to thehousing through a spray bar at around 20 psig, the housing cannot maintain a positive pressureand the oil immediately atomizes, resulting in oil starvation. This manifests itself as asubsynchronous rotor vibration.The solution is to use dummy end seals with a reasonable clearance and to temporally block theopen housing drains. Dummy end seal clearances of around twice the bearing clearance willproduce a reasonable housing pressure of around 10 psig. In this case, the inlet oil exiting the spray bars will not atomize even in a high speed balance vacuum bunker.

[API 684 3.3.3.2]

6.8.8.4.3 The rotor shall be completely assembled including thrust collars with locking collars and any auxiliary such as power take-off gears, overspeed trip assemblies, and tachometer rings for governor overspeed switches

6.8.8.4.4 The drive coupling shall be attached to the rotor via a plate bolted to the end of the shaft. This attachment shall be such as to minimize any unbalance due to eccentricity.

NOTE - In most cases, the facility drive coupling and adapter is adequate to insure the rotor mode shape is

5/6/2023

5/6/2023 Page 95 of 99

simulated at operating speed since the pedestals also substantially depress the second resonant frequency. In some cases, the job-coupling hub with moment simulator may be required, especially for the outboard ends of drive-through machines.

6.8.8.4.5 Pedestals shall be provided by the balance machine vendor.

• 6.8.8.4.6 When specified, in addition to the normal velocity sensors at each pedestal, 2 orthogonally mounted radial non-contacting vibration probes shall be mounted next to the bearings and at mid shaft. All probes shall be at the same circumferential locations.

6.8.8.4.7 When non-contacting vibration probes have been specified, structural resonance frequency of the probes and supports shall be determined after installation of the rotor and probe assemblies in the balance machine.

6.8.8.4.8 Pedestals shall be selected based on the requirements and limitations of Table XXX.

6.8.8.4.9 Adjust lube oil temperature to simulate normal operating conditions.

6.8.8.4.10 Upon completion of the balancing the following data shall be provided for the initial run to operating speed, the stabilized rotor prior to balancing, and for the final balanced rotor with and without pedestal stiffening:a) Bode’, and polar plots for each pedestal velocity probe. b) When proximity probes have been specified: Bode’, cascade, polar, eccentricity (shaft centerline) and filtered (1X) shaft orbital plots of each proximity probe for coast down (without speed detents). Proximity probe data shall be compensated for slow roll mechanical and electrical runout. c) Spectrum (Amplitude versus frequency) plots of rotor at full speed.

6.8.8.4.11 Prior to operating speed balance, the complete rotor shall be slow speed balance checked in the operating speed facility. If the measured unbalance exceeds five times 4W/N the low speed balance and runout records from 6.8.8.4.1 shall be reviewed and the cause for the unbalance determined.

An unbalanced rotor may be caused by conditions such as a bowed rotor, shifted or cocked components, uneven erosion, missing keys, or proud key(s),unbalanced or eccentric drive shaft, a rotor which was assembled without stack balancing, or a rotor which has been coated. The cause of the unbalance and its magnitude will determine the steps which should be taken before running up to speed.

Depending on the cause and magnitude of unbalance, the unbalance may be reduced by operating the rotor at slow-speed, running it partially up-to-speed several times, replacing a component or performing a three plane slow-speed balance.NOTE - The purpose of minimizing the unbalance is to increase the possibility of the rotor successfully transversing its critical speed(s) and reaching operating speed.

6.8.8.4.12 Prior to balancing, the rotor residual unbalance shall be stabilized. This shall be accomplished by :

5/6/2023

5/6/2023 Page 96 of 99

a) Record slow roll (500 rpm-800 rpm) residual unbalance (amount and phase) before running up in speed.

b) Run rotor to120% maximum continuous speed for steam turbines rotors or for compressor rotors to trip speed, hold for 5 minutes. Reduce to maximum continuous operating speed and record residual velocity and phase angle on each pedestal .

c) Reduce speed to 500 RPM to 800 RPM and record slow roll data again.

d) Repeat until slow roll and maximum continuous operating speed residual unbalance and phase angle are consistent.

6.8.8.4.13 Rotate the drive shaft and any drive shaft adaptor plate 180º. Unbalance shall not change by more than 0.0005 “ times the half weight of the drive shaft and adaptor. With purchasers approval, calculation algorithms for correcting the balancing results may be applied to the final rotor balance.

6.8.8.4.14 Balance the rotor with temporary trial weights.

6.8.8.4.15 Permanent balance corrections shall be made per 6.8.8.4.16 through 6.8.8.4.24. These corrections shall be accomplished by moving blades, adding balancing weights if the rotor is designed for balancing weights or by grinding.

6.8.8.4.16 Field accessible balance holes shall not be used for balance corrections.

6.8.8.4.17 Balance weights shall be compatible with disk material and suitable for the operating environment. Record weight, number and location of balance weights. Balance weights shall be staked in place to prevent the weight from backing out in operation.

6.8.8.4.18 When grinding is necessary, grind in the plane where the trial weight was removed.

6.8.8.4.19 For Steam turbines, Axial Compressors of the Disk – Shrunk - On - Shaft design, balancing corrections shall be made on the disks by grinding on the face of the disk dedicated for balance correction or by adding balance weights in a balance groove. Corrections on the disk faces adjacent to the blade root areas, the blade attachment, or other highly stressed regions of the disk is not permitted. The grinding depth of the balance corrections should be limited to approximately 3 mm (1/8 in.). If necessary, the correction grind shall be blended to prevent stress risers and spread out to limit thinning of the disk material.

Refer to API 687 Figure 3.1-1 for an illustration of the Disk-Shrunk-on-Shaft design.

6.8.8.4.20 For Axial compressors of the tie bolt design with axially inserted blading, balance correction shall first be made by moving blades.

5/6/2023

5/6/2023 Page 97 of 99

Resequence the blades if the unbalance exceeds 25 grams at the correction radius (10 in. radius would be 250 gm-in.).

Grinding of the disks should be done after efforts have been exhausted in relocating blading to achieve the balance tolerance.

For non- axially inserted blading, grinding is required on the disks.

Corrections on the disk faces adjacent to the blade root areas, the blade attachment, or other highly stressed regions of the disk is not permitted. The grinding depth of the balance corrections should be limited to approximately 3 mm (1/8 in). If necessary, the correction grind shall be blended to prevent stress risers and spread out to limit thinning of the disk material.

NOTE - Blade weight and location should be available from the blade positioning used during the stacking of the rotor.

6.8.8.4.21For axial compressors of the integral rotor design, and axially inserted blading, balance correction should only be made by moving blades

6.8.8.4.22 After the rotor is balanced within the tolerances of 6.8.8.5 repeat the final balance run with the pedestal stiffening engaged. Rotor balance shall be in accordance with 6.8.8.5

6.8.8.4.23 After operating speed balance, residual unbalance and phase angle readings shall be documented by running the rotor in a low speed balance machine. No corrections shall be made to the rotor.

NOTE - This is done to provide a reference for residual unbalance and phase if the rotor is checked in the future using a low speed balance machine.

SP 6.8.8.5 Unless otherwise specified, the vibration acceptance criteria for operating-speed balancing, with maximum pedestal stiffness at all speeds, measured on the bearing pedestals shall be the lesser of 6.8.8.5.1 or 6.8.8.5.2 .

6.8.8.5.1

a) For MCS less than 3 000 r/min the pedestal vibration shall not exceed 1.8 mm/s (0.098 in /s) RMS.

b) For MCS above 3 000 r/min, the pedestal vibration shall not exceed the greater of (7 400 X 0,707/N) mm/s (291in/s) or 0,707/N mm/s (0.039 in /s) RMS, where N is the speed in r/min.

6.8.8.5.2 For all speeds, the pedestal vibration shall not exceed the following:

SPTF Consider two formulas, one for metric, one for US customary

5/6/2023

5/6/2023 Page 98 of 99

Velocity, mm/s RMS = 1.881 * 0.2 * W * N / K

Where: 0.2 is the g force on the pedestals W is the bearing reaction in lbf N is the speed in r/min K is the stiffness in lbf/in

6.8.8.5.3 When non-contacting vibration probes have been specified in 6.8.8.4.6 Maximum allowable shaft vibration (filtered compensated 1X) shall not exceed 1.0 mil peak-to-peak at any response or 0.5 mil peak-to-peak over operating speed range.

6.8.8.6 During the mechanical running test of the machine, assembled with the balanced rotor, operating at its maximum continuous speed or at any other speed within the specified operating speed range, the peak-to-peak amplitude of unfiltered vibration in any plane, measured on the shaft adjacent and relative to each radial bearing, shall not exceed the following value or 25.4 μm (1 mil), whichever is less:

In SI units:(10a)

In U.S. Customary units

(10b)

where

A = amplitude of unfiltered vibration, m (mil) true peak-to-peak,

N = maximum continuous speed, r/min.

At any speed greater than the maximum continuous speed, up to and including the trip speed of the driver, the vibration level shall not increase more than 12.7 µm (0.5 mil) above the maximum value recorded at the maximum continuous speed.

NOTE - These limits are not to be confused with the limits specified in 6.8.3 for shop verification of unbalanced response.

6.8.8.7 Electrical and mechanical runout shall be deter-mined by rotating the rotor through the full 360 degrees sup-ported in V blocks at the journal centers while continuously recording the

5/6/2023

5/6/2023 Page 99 of 99

combined runout with a non-contacting vibration probe and measuring the mechanical. runout with a dial indicator at the centerline of each probe location and one probe-tip diameter to either side.

NOTE - The rotor runout determined above generally may not be reproduced when the rotor is installed in a machine with hydrodynamic bearings. This is due to pad orientation on tilt pad bearings and effect of lubrication in all journal bearings. The rotor will assume a unique position in the bearings based on the slow roll speed and rotor weight.

6.8.8.8 Accurate records of electrical and mechanical runout, for the full 360 degrees at each probe location, shall be included in the mechanical test report (see 6.8.3.1.1).

6.8.8.9 If the vendor can demonstrate that electrical or mechanical runout is present, a maximum of 25% of the test level calculated from Equation 6 or 6.4 mm (0.25 mil), which-ever is greater, may be vectorially subtracted from the vibration signal measured during the factory test. Where shaft treatment such as metallized aluminum bands have been applied to reduce electrical runout, surface variations (noise) may cause a high frequency noise component which does not have an applicable vector. The nature of the noise is always additive. In this case, the noise shall be mathematically subtracted.

5/6/2023