APPENDIX 3DEFINITIONS

3-1 INTRODUCTION

This Appendix contains definitions of terms generallyused in this Division. Definitions relating to specificapplications, such as for layered vessels, may be foundin related parts of this Division.

3-2 DEFINITION OF TERMS

acceptance by the Inspector —where words such as“acceptance by the Inspector” and/or “accepted by theInspector” are used in this Division, they shall beunderstood to mean that the Inspector has reviewed asubject in accordance with his duties as required bythe rules of this Division and after such review is ableto sign the Certificate of Inspection for the applicableManufacturer’s Data Report Form. Such words donot imply assumption by the Inspector of any of theresponsibilities of the Manufacturer.

angle joint — a joint between two members locatedin intersecting planes between 0 deg. (a butt joint) and90 deg. (a corner joint)

basic material specification —a description of theidentifying characteristics of a material (product form,ranges of composition, mechanical properties, methodsof production, etc.) together with the sampling, testing,and examination procedures to be applied to productionlots of such material to verify acceptable conformanceto the intended characteristics

bolt — a threaded fastener with a head on one end

calculated test pressure —the requirements for de-termining the test pressure based on calculations areoutlined in UG-99(c) for the hydrostatic test and inUG-100(b) for the pneumatic test. The basis for calcu-lated test pressure in either of these paragraphs is thehighest permissible internal pressure as determined bythe design formulas, for each element of the vesselusing nominal thicknesses with corrosion allowancesincluded and using the allowable stress values givenin Subpart 1 of Section II, Part D for the temperatureof the test.

350

certificate of compliance —a document by whichthe material manufacturer or supplier certifies that thematerial represented has been produced and tested inaccordance with the requirements of the basic materialspecification shown on the certificate. Signatures arenot required to appear on certificates of compliance.Objective evidence of compliance with the requirementsof the material specification shall be maintained in therecords of the material manufacturer or supplier.

clad vessel —a vessel made from a base materialhaving a corrosion resistant material either integrallybonded or weld metal overlaid to the base of lessresistant material

design pressure —the pressure used in the design ofa vessel component together with the coincident designmetal temperature, for the purpose of determining theminimum permissible thickness or physical characteris-tics of the different zones of the vessel. When applicable,static head shall be added to the design pressure todetermine the thickness of any specific zone of thevessel (see UG-21).

design temperature —see UG-20

efficiency of a welded joint —the efficiency of awelded joint is expressed as a numerical (decimal)quantity and is used in the design of a joint as amultiplier of the appropriate allowable stress valuetaken from the applicable table in Subpart 1 of SectionII, Part D (see UW-12)

layered vessel —a vessel having a shell and/or headsmade up of two or more separate layers

lined vessel —a vessel having a corrosion resistantlining attached intermittently to the vessel wall

liquid penetrant examination (PT) —a method ofnondestructive examination which provides for the de-tection of imperfections open to the surface in ferrousand nonferrous materials which are nonporous. Typicalimperfections detectable by this method are cracks,seams, laps, cold shuts, and laminations.

magnetic particle examination (MT) —a method ofdetecting cracks and similar imperfections at or nearthe surface in iron and the magnetic alloys of steel.

COPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling ServicesCOPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling Services

3-2 APPENDIX 3 — MANDATORY 3-2

It consists of properly magnetizing the material andapplying finely divided magnetic particles which formpatterns indicating the imperfections.

material — any substance or product form which iscovered by an SA, SB, or SFA material specificationin Section II or any other material permitted by the Code

material manufacturer —the organization which per-forms or supervises and directly controls one or moreof the operations which affect the material propertiesrequired by the basic material specification. The materialmanufacturer certifies the results of one or more ofthe tests, examinations, repairs, or treatments required bythe basic material specification. When the specificationpermits certain specific requirements to be completedlater, those incomplete items must be noted.

material supplier —the organization which suppliesmaterial furnished and certified by a material manufac-turer, but which does not perform any operation intendedto affect the material properties required by the basicmaterial specification. The material supplier may per-form and certify the results of tests, examinations,repairs, and treatments not performed by the materialmanufacturer.

Material Test Report —a document, or documents, onwhich are recorded the results of tests, examinations,repairs, or treatments required by the basic materialspecification to be reported. Supplementary or specialrequirements in addition to the requirements of thebasic material specification may also be included onthe Material Test Report. All such documents shallidentify the applicable material specification and shallbe identified to the material represented. When preparinga Material Test Report, a material manufacturer maytranscribe data produced by other organizations providedhe accepts responsibility for the accuracy and authentic-ity of the data and maintains a file containing the testreport from the originator of the data. In such instances,the material manufacturer shall identify on the MaterialTest Report the source of the data and the location ofthe file containing the test report from the originatorof the data. Signatures are not required to appear onMaterial Test Reports. A material supplier shall nottranscribe data certified by a material manufacturer butshall furnish a copy of that certification, supplementedas necessary by additional documents which certify theresults of tests, examinations, repairs, or treatmentsrequired by the basic material specification and per-formed by the material supplier.

maximum allowable stress value —the maximum unitstress permissible for any specified material that maybe used in the design formulas given in this Division(see UG-23)

351

maximum allowable working pressure —the maximumgage pressure permissible at the top of a completedvessel in its normal operating position at the designatedcoincident temperature for that pressure. This pressureis the least of the values for the internal or externalpressure to be determined by the rules of this Divisionfor any of the pressure boundary parts, including thestatic head thereon, using nominal thicknesses exclusiveof allowances for corrosion and considering the effectsof any combination of loadings listed in UG-22 whichare likely to occur (see UG-98) at the designatedcoincident temperature [see UG-20(a)]. It is the basisfor the pressure setting of the pressure relieving devicesprotecting the vessel. The design pressure may be usedin all cases in which calculations are not made todetermine the value of the maximum allowable workingpressure.

membrane stress —the component of normal stresswhich is uniformly distributed and equal to the averagevalue of stress across the thickness of the section underconsideration

normal operation —operation within the design limitsfor which the vessel has been stamped. [See UG-116(a).] Any coincident pressure and temperature duringa specific operation are permissible, provided they donot constitute a more severe condition than that assumedin the design of the vessel.

operating or working temperature —the temperaturethat will be maintained in the metal of the part of thevessel being considered for the specified operation ofthe vessel (see UG-20 and UG-23)

operating pressure —the pressure at the top of avessel at which it normally operates. It shall not exceedthe maximum allowable working pressure, and it isusually kept at a suitable level below the setting ofthe pressure relieving devices to prevent their frequentopening (see M-9).

porosity —gas pockets or voids in metal

primary stress —a stress developed by the imposedloading which is necessary to satisfy the simple lawsof equilibrium of external and internal forces andmoments. Primary stress can be either membrane orbending stress.

Primary membrane stress may be of two types:general and local. A general primary membrane stressis one which is so distributed in the structure thatno redistribution of load occurs as a result of yielding.A local primary membrane stress is one which isproduced by pressure or other mechanical loading andwhich is associated with a primary and/or discontinuityeffect.

COPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling ServicesCOPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling Services

3-2 2001 SECTION VIII — DIVISION 1 3-2

Examples of primary stress are:(a) general membrane stress in a circular cylinder

or a spherical shell due to internal pressure or todistributed loads;

(b) bending stress in the central portion of a flathead due to pressure.

radiographic examination (RT) —a method of detectingimperfections in materials by passing X-ray or nuclearradiation through the material and presenting their imageon a recording medium

safety valve set pressure —See ASME PTC 25

stationary pressure vessel —a pressure vessel to beinstalled and operated as a fixed geographical location

stud —a threaded fastener without a head, with threadson one end or both ends, or threaded full length

thickness of vessel wall

352

(a) design thickness —the sum of the requiredthickness and the corrosion allowance (see UG-25)

(b) required thickness —that computed by the formu-las in this Division before corrosion allowance is added(see UG-22)

(c) nominal thickness —except as defined in UW-40(f) and modified in UW-11(g), the nominal thicknessis the thickness selected as commercially available, andsupplied to the Manufacturer. For plate material, thenominal thickness shall be, at the Manufacturer’s option,either the thickness shown on the Material Test Report{or material Certificate of Compliance [UG-93(a)(1)]}before forming, or the measured thickness of the plateat the joint or location under consideration.ultrasonic examination (UT) —a method for detectingimperfections in materials by passing ultrasonic vibra-tions (frequencies normally 1 MHz to 5 MHz) throughthe materialvessel Manufacturer —any Manufacturer who con-structs an item such as a pressure vessel, vessel compo-nent, or part in accordance with rules of this Divisionand who holds an ASME Certificate of Authorizationto apply the Code Symbol Stamp to such an item

COPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling ServicesCOPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling Services