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DRAFT IN WIDE CIRCULATION DOCUMENT DESPATCH ADVICE

REF: DATE PCD 3:P2/T-1 03-03-2006

Technical Committee: Petroleum, Lubricants and Related Products Sectional Committee, PCD 3

i) All interested members of PCDC ii) All members of Petroleum Lubricants and Related Products Sectional Committee, PCD 3; iii) All others interested.

Dear Sir, Please find enclosed the following documents: Doc: No. Title PCD 3(2348)C Code of Practice for Hot Tapping, Stopple Plugging/Line

Plugging of Pressurized Natural Gas Pipelines Kindly examine this draft and forward your views stating any difficulty which you are likely to experience in your business or profession, if this is finally adopted as a revised standard. Last date for comments is : 3 April 2006 Comments if any, may please be made in the format as given overleaf and mailed to the undersigned at the above address. The document is also hosted on BIS website www.bis.org.in. Thanking you, Signature : Name : Dr D.K. Chaudhuri Designation Sc.F & Head (PCD) Encl: As above.

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FORMAT FOR SENDING COMMENTS ON BIS DOCUMENTS [Please use A4 size paper only and type within fields indicated. Comments on each clause/ subclause be started on a fresh paper. Information in column 3 should include reasons for the comments and suggestions for modified wording of the clause when the existing text is found not acceptable. Adherence to this format facilitates Secretariat’s work]

NAME OF THE COMMENTATOR/ORGANIZATION DOC NUMBER AND TITLE: SL. NO. (1)

Clause, Sub-clause, PARA NO. COMMENTED (2)

COMMENTS/SUGGESTIONS (3)

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Draft For Comments Only Doc: PCD 3(2348)C March 2006

BUREAU OF INDIAN STANDARDS

Draft Indian Standard

CODE OF PRACTICE FOR HOT TAPPING, STOPPLE PLUGGING/LINE PLUGGING OF PRESSURIZED NATURAL GAS PIPELINES

ICS No. 75.200 Not to be reproduced without the permission of BIS or used as STANDARD

Last date for receipt of comments is 3 April 2006

Warning:

a) Persons using this code should be familiar with the normal operation/ practices of hot tapping and line plugging. This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliances with the existing national regulatory conditions.

b) Compliance with this document may involve the use of some patent and/or propriety equipment/accessories. BIS shall not be held responsible for identifying any or all such patent rights and takes no position concerning the evidence, validity and scope of the patents.

FOREWORD (Formal clauses will be added later) The procedure for cutting an opening into an operating pipeline (main, storage tank and pressure vessel) and connecting branch piping while the line has product under pressure and / or flowing conditions is referred to as “Hot Tapping”, while the procedure to isolate a Pipeline section, for repair or modification, without any interruption in the line flow, is called as Stopple Plugging/Line Plugging. Stopples acts as temporary block valves, that can be installed anywhere in a piping system after the hot tapping operations of appropriate sizes. Hot tapping is needed to gain safety access to the pipeline/Storage tank contents, for delivery to another source, to accept additional product from new or untapped source, to obtain information on internal pipeline conditions and to install pig signals/corrosion probe/Chemical Injection point/sampling point etc. It is also needed to create by-pass and to isolate a section of run pipe for repair or modification without interrupting the flow. Stopple Plugging/Line Plugging are needed for tapping for branch connection, removal of stuck pig / foreign material, arrest Leakage without much loss of product, plant Modification / Revamp of existing plant and disaster management.

This operation can be carried out at different temperature, pressure, flow & on various fluids depending on the requirement. These can be carried out on different pipe materials.

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Evaluation of site specific conditions needs to be considered before preparation of the Hot tapping operation.

Presently API 2201 – “Procedure for Welding or Hot tapping on equipments in service “is being followed, mainly in Hydrocarbon Industry, world wide. The API 2201 deals with the Hot tap Welding procedures & hot tapping. This procedure mainly deals with the Hot tap welding and less emphasis has been given to hot tapping. However, it doesn’t contain any information related to the stoppling & plugging operation, operation related with installation of completion plug, safety consideration for hot tapping stoppling and plugging operation of natural gas /RLNG pipelines and maintenance philosophy for hot tapping, plugging machines and its accessories. Hence the need has been felt to frame a comprehensive document covering all the aspects related to Hot tapping & Stoppling operation. As the Indian Industry has grown many folds, formulation of an internationally acceptable Indian standard and/or code of practice has thus become necessary.

The aim for the present code is to cover the basic requirement of safety procedure and equipments for Hot Tapping work to be carried out on high pressure Natural Gas pipeline and pressure vessels. The purpose of this code of practice is to cover the requirement of material, equipments, and accessories for Hot tapping and Stopple Plugging operations of high pressure pipelines. It also covers the operational safety considerations, procedures for Hot Tapping, welding, inspection and maintenance philosophy.

Considerable assistances have been derived from standards such as API 2201 and API1107, API1104,SSPC-VIS-1, ASME codes viz ASME B31.4, ASME B 31.8, ASME B 16.9, ASME B 16.25, ASME sec VIII, ASME sec IX, ASME II A ,IIB & IIC, ASTM A370, MSS-SP-53,and MSS-SP-75 publications, during preparation of the standard. Assistances have also been taken from “Hot tapping vendor guidelines” and O&M manual and in-house developed procedures of Gas Authority of India Limited (GAIL). In using this standard the relevant statutory rules and the requirements framed there under by the respective authorities shall be borne in mind.

1 SCOPE AND FIELD OF APPLICATIONS:

1.1 This code of practice covers the minimum requirements of materials, equipments and accessories for hot tapping and stopple plugging/line plugging operations of natural gas and re-gassified liquefied natural gas pipelines. It covers the minimum safety requirements to be maintained during welding, cutting and plug setting etc. while carrying out the hot tapping and stopple plugging/line plugging operations on pipelines. Checklists have also been included (see Annex C) for the purpose of carrying out inspection, testing of the pipelines before, during and after the operations, in addition to the maintenance schedule.

1.2 This code lays down the guidelines and methods for cutting opening into an operating pipeline and connecting branch piping while the line has product under pressure and/or flowing conditions, also for the replacement/modification of a section of Pipeline under operation. 1.3 The code applies where hot tapping is used for gaining safe access to the pipeline contents for delivery to another source, accepting additional product from a new or untapped

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source, obtaining information on internal pipeline conditions and installation of branch connection, isolation valves etc. on the line under operation. It is also applicable for isolation of a section of operating line for repair, relocation, addition, modification etc. without interrupting the flow and creation of a bypass along with installation of pig signal, corrosion probe or coupon, chemical injection point, sampling point and other online devices as required.

2 NORMATIVE REFERENCES:

The following Indian Standards contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below:

(will be included later)

3 DEFINITIONS:

3.1 Hot Tapping: Hot tapping is a process which involves cutting a hole in the operating pipeline under pressure with appropriate hot tapping machine. 3.2 Stopple Plugging/Line Plugging: Isolation of a section of run pipe for repair or modification without interrupting the line flow is called as Stopple Plugging/Line Plugging. 3.3 Hot-Tap: The procedure for cutting an opening into an operating pipeline (main, storage tank, pressure vessel) and connecting branch piping while the line has product under pressure and/or flowing conditions, is referred to as a "hot-tap". 3.4 Hot-Tap welding: Welding that is required to attach a branch connection fitting (hot-tap fitting) to an operating pipeline, is called “Hot-Tap welding". 3.5 Cutters: The cutter is a mild steel shell with alloy cutting tips, silver-soldered to the cutting edge of the cutter shell. There are many types of cutters each with specific function. 3.6 Pilots: Pilots are specially designed drills which are used to make the first hole into the pipeline. This gives the operator access to the pipeline media and the pipeline pressure. The pilots acts as a centering pin for the cutter to assure a round center hole into the pipeline wall. It is the vehicle for recovering the coupon which has been removed from the pipe as a result of the tap. 3.7 Adapters: Adapters are found in many shapes, sizes and configurations. Main function of adaptor is to provide housing to the cutter assembly and the coupon after completion of the cutting operation. 3.8 Valves: Valve selection is a function of the result to be attained when the hot tap is completed. If the hot tap is being performed to allow a STOPPLE or temporary bypass to be installed and if the valve will be later recovered, then a valve with a short face-to-face dimension is the best choice.

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3.9 Hydraulic Power Unit: To supply the Hydraulic oil for operating the Hot tapping Machine, Sandwich valves & Hydraulic cylinders. 3.10 Fitting Design: Fittings come in a wide variety ranging from small threaded fittings to full-opening split tees. Depending upon the requirement the fittings are available and manufactured with Lock O Ring (LOR) Flange with Pig guide bar /LOR completion plug. Some of the choices available for the pipeline operator are flat nipple scarfed nipple, 3 ways Tee; Full encirclement split Tee, Reinforced Tee, BW Tee, Spherical Tee, Weldolets etc. 3.11 Lock O Ring: A Lock O Ring completion plug installed in a compatible Lock O Ring fitting permits removal of the Tapping valve. Reentry into the line at a future date is usually possible by removing the completion plug. 3.12 Stopple Plugging machine: It is a machine used for temporarily blocking the flow in a pipeline by insertion of a stopple plugging head along with sealing element through a tapped hole into the pipeline. 3.13 Hot tapping machine: A tapping machine is basically a long tube (boring bar) inside a pipe (the frame). Inside the tube is a feed screw, which automatically extends the boring the bar, whenever bar is rotating. Tapping machine can be driven by air or hydraulic motor or operated by hand. There are various models with different ranges of taping machine, which can tap from ¼” to 60”. Depending on the requirement, suitable hot tapping machine is selected.

4 TYPES OF HOT TAP

Hot tapping is performed normally at an angle perpendicular to the centre line of pipeline or otherwise. 4.1 At an angle perpendicular to the centre line of pipeline - Split Tee shall be installed as shown in the following fig.1 For installation of the Split Tee standard welding procedure shall be followed,

Fig 1 Hot Tapping at an angle perpendicular to the centre line of pipeline

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4.2 At an angle other than 90 degree

When making a tap at any angle other than 90 degree between centre line of tapping machine and centre line of pipeline, certain precautions shall be noted.

4.2.1 The pilot drill shall have a starting surface that is 90 degree to the centre line of the pilot. There is a 5° tolerance. 4.2.2 Pilot drill should extend beyond cutter enough to complete pilot tap before cutter engages the pipe or vessel. 4.2.3 Provision shall be made to retain the coupon. With normal tapping procedures, the U-rod may get damaged or destroyed by rotating in the angled pilot tap.

4.2.4 Cutter shall have enough inside depth to allow room for the oblong coupon. 4.2.5 The most common method of providing the starting surface is to weld an angle iron so that one leg of angle iron is parallel to the flange. This shall be parallel when measured with the length of the pipeline or across the pipeline. Use formula for T" to determine width of angle Iron for trimming. 4.2.6 For the pilot drill to perform as a pilot or guide, the drill should penetrate the pipe before the cutter makes first contact. Minimum pilot extension can be determined by formula for “E”. Additional pilot length is not detrimental to the tap. However, extra long pilot drills shall be given due consideration concerning tapping machine adapter and size of pipe or vessel so that pilot does not make unplanned contact before tap is completed. 4.2.7 For tapping angles up to 30 degrees from perpendicular, normal tapping procedures with R-rod design pilots are satisfactory. At angles greater than 30 degrees, special pilots or alternate procedures shall be used. Usually the least expensive and most readily available coupon retainer is to use following the procedures. 4.2.7.1 Measure from tip of pilot drill to top end of U-rod that is expected to retain coupon. 4.2.7.2 Calculate tapping distance to move pilot drill into pipeline or vessel the distance measured in 4.2.7.1. Add 1/2" for safety factor. 4.2.7.3 Remove U-rods from pilot drill. 4.2.7.4 Mount tapping machine on valve. Use two oversized bolts or other means to establish line-up that can be repeated. 4.2.7.5 Tap distance determined in 4.2.7.2. 4.2.7.6 Remove tapping machine and install new U-rod. 4.2.7.7 Remount tapping machine in same alignment as 4.2.7.4. 4.2.7.8 Extend (without rotation) the cutter and pilot to the position of.4.2.7.5. 4.2.7.9 Complete tap to full tapping distance.

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4.2.8 Calculate distance "N" as minimum cutter depth to complete tap. Do Not attempt tap with cutter shorter than “N" inside clear dimension. If special cutter required, inside length should be “N" + ½” as minimum.

Where A = Angle from perpendicular D = Cutter O.D. d = Cutter I.D. E = Pilot extension L = Width of leg of angle iron N = Nesting room for coupon (NO SAFETY FACTOR) R = 1/2 D T = Trim width of leg of angle iron W = Wall thickness of pipe or vessel E = R x Tangent “A” + W x Secant "A”. N = d x Tangent “A” + W x Secant "A” T = L x Tangent Angle “A”

Tapping distance after cutter contact, TD = D x Tangent "A" + (W x Secant "A") Angle ( degree) Tangent Secant 5 0.087 1.006 10 0.176 1.015 15 0.268 1.035 20 0364 1.064 25 0.466 1.103 30 0.577 1.155 35 0.700 1.221 40 0.839 1.305 45 1.000 1.414

NOTE:

1. For angles not shown, use next larger scale. 2. For angles greater than 45°, check with Services Technical Section for recommendation. 3. (1.5 x W) may be substituted for (W x Secant “A") as a safe approximation.

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5 CLASSIFICATION

5.1 Hot Tapping Machine: Depending upon the requirement hot tapping machine can be selected ranging from ¼” to 60”. While selecting the hot tapping machine content of pipeline, pressure, flow rate, temperature, sizes etc need to be evaluated.

5.2 Adapters:

5.2.1 Adapters for standard cutter: Used for cutting operations with standard cutter. 5.2.2 Adapters for stopple cutter: used for cutting operation with stopple cutter where line stoppling is required. 5.2.3 Stopple Housing: Used for plugging operations as housing for the plugging head and sealing element.

5.3 Valves:

5.3.1 Sandwich Valve 5.3.2 Full bore ball valve, gate valve with inner bore matching with the cutter size.

5.4 Stoppling Fitting/Split Tee:

5.4.1 Split Tee with LOR flange, LOR Plug with Scarfed nipple and BF 5.4.2 Split Tee with LOR flange, Pig Guide bar and BF 5.4.3 Split Tee with normal wnrf flange. 5.4.4 Threaded o ring fitting with blind

5.5 Weldolet:

5.5.1 Weldolet with LOR flange, LOR plug, with Scarfed nipple and BF 5.5.2 Weldolet with Pig Guide bar, LOR plug and BF 5.6 Plugging machine: Plugging machines are available for different ranges depending on the class, line pipe size, & other pipeline parameters. The selection of the plugging machine can be done on the basis, on above parameters and requirement. 5.7 Plugging Head: Plugging head can be selected depending upon the line pipe size and other pipeline parameters. 5.8 Sealing element: Material & Sizes of the Sealing element can be selected depending on the pipeline parameters, like thickness & size of the pipeline.

6.0 DETAILS OF TAPPING MACHINES, TOOLS AND ACCESSORIES

6.1 Tapping Machines

A variety of Hot tapping machines are available in the market with tapping capability of ¼” to 60 “. Hot tapping machines are being designed as per the specifications depending upon the range of tapping size, boring bar travel distance and pipeline parameters. (i.e. Product, temperature, flow rate, pressure etc).

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Presently on a broad area, machines can be classified as:

Machine Capability Maximum travel distance of Boring bar

Maximum Range of Pressure & temperature

¼” to 4 “ Up to 28 “ Up to 1440 psi @ 100 F &

700 psi @ 700 F 4” to 16 “ Upto 66 “ Upto 1440 psi @ 100 F &

700 psi @ 700 F 12” to 36 “ Upto 72 “ Upto 1440 psi @ 100 F &

700 psi @ 700 F 12” to 42 “ Upto 108 “ Upto 1440 psi @ 100 F &

700 psi @ 700 F 30” to 60 “ Upto 108 “ extended upto

130 “ Upto 1200 psi @ 200 F

6.2 Plugging Machines: A variety of plugging machines are available in the market with plugging capability of different ranges.

Plugging machines are being designed as per the specifications depending upon the range of the plugging size, control bar travel distance, and pipeline parameters (i.e. Product, Temperature, flow rate, pressure etc).

On a broad area, plugging machines can be classified as

Machine Capability Maximum travel distance of control bar

Maximum Range of Pressure & temperature

6” to 12 “ Upto 72 “ Upto 1800 psi @ 180 F 14” to 20 “ Upto 102 “ Upto 1800 psi @ 180 F 22” to 34 “ Upto 140” Upto 1800 psi @ 180 F 34” to 48 “ Upto 140” Upto 1800 psi @ 180 F

6.3 Tools:

Tools Type Usage Size Standard Cutter Used for Hot Tapping for taking

branch Connection or for the purpose except stoppling

2 “ to 60”

Stopple Cutter Used for Hot Tapping for the purpose of Stoppling

2 “ to 60”

Cutters

Tank Cutter Used for Hot tapping comparatively at a flatter surface

2 “ to 30”

Standard Drill For Tapping Drill ¼” to 3” Drill Pilot drill Used along with the saw cutter (

Standard, Stopple, tank)

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Adaptor for Standard Cutter

Used for the housing for standard & tank cutter assembly

2 “ to 60”

Adaptor for Stopple Cutter

Used for the housing for stopple cutter assembly

2 “ to 60”

Adaptors

Line Stop housing Used for housing the plugging head alongwith the sealing element

Upto 48”

6.4 Accessories:

Accessory Type Usage Size Split Tee with WNRF Flange

For creation of by pass , branch connection, where retrieval of tapping valve and installation of pig guide bar is not required

4 “ to 60” depending on the line pipe size & tapping size

Split Tee with LOR Flange

Used where, Stoppling , retrieval of valve , installation of pig guide bar is required

4 “ to 60” depending on the line pipe size & tapping size

Fittings

Threaded O Ring Fitting

Used where, for branch connection, purging & pressure equalization.

¼ “ to 3” depending on the line pipe size & tapping size

Valves Sandwich valve Used with Hot tapping machine, line stoppling machine and installation of completion plug.

4” to 60 “

Full Bore Valve ( Ball , Gate)

Used with Hot tapping machine.

¼” to 60”

Plugs Completion Plug Used for retrieval of valve and seal the tapping

4” to 60”

Pig Guide bar Used to facilitate normal pigging operation of pipeline

4” to 60”

7.0 STEPS INVOLVED IN HOT TAPPING AND LINE /STOPPLE PLUGGING:

7.1. For Hot tapping:

7.1.1 Welding of fittings (see Cl.10) 7.1.2 Installation of valves on welded fittings. 7.1.3 Assembly of cutter and pilot drill with hot tapping machine. 7.1.4 Measurements for Hot tappings, Stoppling & setting of Completion plug. 7.1.5 Installation of Hot Tapping machine on valve. 7.1.6 Hydro-testing of complete assembly. 7.1.7 Operation of Hot Tapping. 7.1.7 Completion of Hot tapping & removal of machine

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7.2. Creation of by Pass, if required.

7.3. Stoppling/Plugging.

7.4. Cutting, Modifiaction of the isolated section.

7.5. Removal of the stopple Plugs.

7.6. Setting completion plug.

7.7. Removal of the valve and installation blind flange.

8 PROCEDURE FOR HOT TAPPING AND LINE /STOPPLE PLUGGING

8.1 Hot Tapping

8.1.1 Necessary arrangement for fire tender/fire extinguisher etc. are to be ensured

8.1.2 Removal of existing Coal tar enamel or PE coating of pipeline, if any.

8.1.3 UT to determine health of pipe and thickness at place of welding

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8.1.4 Depending on the actual thickness ASME Hoop stress formula, recommendation of Hot tapping machine manufacturer, the pipeline parameters may be adjusted within acceptable limits if required. The safe internal pressure of the new pipeline is to be reduced as per 10.18.5. 8.1.5 Installation of fitting/stopple fitting. 8.1.6 Checking of L.O.R. arrangement of stopple fitting before welding. 8.1.7 Welding of fitting as per procedure defined para 9.00 in this document. 8.1.9 Installation of spiral wound metallic gasket. 8.1.10 Installation of Sandwich valve/ full bore ball/gate valve. 8.1.11 Assembly of Hot tapping machine with tapping adapter, saw cutter and pilot drill on cutter holder. Check for alignment between T.M. Adapter and saw cutter.

A typical tapping set up for tapping a angle 90 Deg to the centre line of the pipeline

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8.1.12 Install bleeder valve on T.M. adapter. 8.1.13 Mounting of Hot tapping machine on the valve. 8.1.14 Pressure test the assembly keeping sandwich valve open. 8.1.15 Installation of hydraulic hoses of power unit to tapping machine. 8.1.16 Measurement of all the distances required for hot tapping stopple plugging, and for setting of completion plug. ( Appendix-A & B) 8.1.17 Ensure bleeder valve is open. 8.1.18 Start the tapping machine after bringing down the pilot drill to the top of pipe. Note the reading of measurement rod. 8.1.19 Make a mark on the measuring rod indicating the distance , where the cutting shall be competed.. 8.1.20 Adjust the stopper accordingly. 8.1.21 As soon as the pipe is punctured with pilot drill, gas will bleed off bleeder valve. Close the bleeder valve. 8.1.22 After the tapping is complete i.e., the marking done at 2nd place has reached then, stop the tapping machine. 8.1.23 Disengage the clutch and lower down the boring bar manually, so as to ensure the completion of the cutting operation. 8.1.24 After confirmation regarding the completion of cutting operation, disengage the clutch and lift the boring bar to the top position by lowering crank./ manually depending on the features available in the machine. 8.1.25 Close the sandwich valve. 8.1.26 Bleed off the gas in the tapping machine. 8.1.27 Remove the tapping machine. 8.2 Creation of by Pass, if required must be done as mentioned in 8.1.1 to 8.1.25 on both sides of the pipeline section either by installing the prefabricated tested pipe section/modified pipe sections or by opening the valve on both sides of the pipeline section and allowing the flow through this by pass line

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8.3 Stoppling/Plugging.

8.3.1 Steps 8.1.1 to 8.1.25 are carried out on both sides of the P/L Section. Install housing on the stopple plugging machine. Then install plugging head on the control bar of the stopple plugging machine. Now install sealing element on the plugging head. Take the measurements to calculate the lower in distance for control bar.

8.3.2 Install stopple plugging machine on the valve and connect the hydraulic hoses. Connect bladder valve in the housing and also connect equalization line with 2” tapping for pressure equalization across the plugging head. Disengage the bar lock clamp on stopple plugging machine. Equalize the machine with Line pressure through 2” by pass line /sandwich valve by pass line.

8.3.3 Open the valve. Ensure a 2” temporary by pass line to be open. Lower down the plugging head and by setting up the plugging head into the Pipeline as per the measurement, block the supply of the product in pipeline section, thus isolating the section. Here it is to be ensured that first set the downstream plugging head then upstream plugging head.

8.3.4 Accomplishing the above 8.3.1 to 8.3.3 for both sides of the pipeline sections results in full supply through by- pass line and isolation of pipeline section. Engage the Bar lock clamp on stopple plugging machines. Remove the hydraulic hoses.

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8.4 . Cutting, Modification of the isolated section.

Cutting, modification of the isolated section shall be done as per requirement. Also ensure that the isolated section has been completely sealed & verified satisfactorily or else it results in safety hazard, injury to personnel & property damage.

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8.5 Removal of the stopple Plugs.

8.5.1 After cutting and welding of the isolated P/L Section with necessary modifications, remove the plugs from both the sides of the pipeline section. Equalize the pressure across the plugging head , before its removal .Connect the hydraulic hoses. Unlock the bar lock clamp on control bar before removal of the plugging head. Ensure that first set the upstream plugging head is removed & then downstream the plugging head. 8.5.2 Close the valves of the main by pass line to allow the supply of the product through the main line. Remove the stopple plugging machines, after closing the valves and venting/removal of product from machine.

8.6 Setting completion plug.

8.6.1 Weld coupon on the scarfed nipple of the completion plug. Smooth the rough edges of the coupon with the grinder. Burn off approximately 1” diametrically to adjust minor mis-alignment by down standing legs of the coupon. Ensure the proper functioning of check valve on completion plug. Install the Completion plug on the hot tapping machine. 8.6.2 Install Hot Tapping machine on the Valve. Ensure equalization of pressure above and below the plug through 2” by pass line /sandwich valve by pass line, till the completion of the job.

8.6.3 Open the valve. Lower down the completion plug at measured distance. Lock the completion plug with the lock o rings on the LOR Flange of the split tee. Release the plug holder from boring bar and retract the boring bar. Close the valve and remove the Hot Tapping machine.

8.7 Removal of the valve and installation of blind flange.

Remove the valve from the flange and put the blind after setting of the completion plug and removal of the hot taping machine. Apply the Coal tar enamel or PE coating of pipeline, if any.

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9 SAFETY CONSIDERATIONS DURING HOT TAPPING AND LINE /STOPPLE PLUGGING

9.1 Pipeline conditions must be known in order to assert welding ability. The product, along with its velocity and temperature, and the atmospheric conditions at the job site play an important role during hot tapping and line/stopple plugging. These factors can affect the safety of welding. 9.2 Knowledge of pipeline quality, including material specification, carbon equivalent, external and internal corrosion, lamination in the pipe wall, and wall thickness is critical. 9.3 Welding parameters like procedures, including type of electrodes and size, heat input (volts, ampere, speed of electrode, angle of electrode) preheat and welding sequence must be determined. 9.4 Inspection before, during and after installation of fitting is vital. 9.4.1 Before installation information about magnetic particles, inspection of pipe at fitting location ultrasonic inspection for possible internal corrosion and verification of wall thickness are necessary. 9.4.2 During installation ensure that weld procedures are maintained, including precautions for keeping electrodes dry (Use of low-hydrogen electrodes is recommended). 9.4.3 After installation check for the magnetic particle. It is recommended that the welds be inspected after 48 hours of completion, to detect any possible delayed hydrogen cracking. 9.4.4 Several other areas of concern are to be taken into account during hot-tap welding including heat-affected zone cracking, blow-through and unstable pipeline contents such as ethylene. However, it is highly important to check the cracks in the heat-affected zone of the filled weld caused by hydrogen trapped in the weld metal during the rapid cooling process. 9.5 Preventive Measures: 9.5.1 The following are the guidelines to prevent blow-through: 9.5.1.1 Blow – through can be prevented using low hydrogen electrodes and by checking the contents of the line for continuity in the flow. 9.5.1.2 The heat balance between the fitting and the pipe must be taken care with the help of electrode. 9.5.1.3 The minimum pipe wall thickness shall be 6.35 mm or greater using normal welding practice, as per research and industrial experience. 9.5.1.4 The pressure in the pipeline should be reduced according to the ASME Gas Piping Standards (see ASME/ANSI B 31.8). 9.5.1.5 Ensure that Qualify welders and weld procedures to applicable codes are followed.

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9.5.1.6 Pre- heat the area on the pipe, where fitting is to be installed, to remove moisture from the surface. 9.5.2 Inspection and testing of the field weld is an important procedure and shall be performed as mentioned the Cl. 11. 9.5.3 No flow conditions can allow the contents of a pipe to reach a higher temperature than with flow conditions. Pipe contents with impurities (oxygen) at higher temperatures are more likely to ignite. Flow conditions help to dissipate heat but serve to speed up the quench rate which is a factor in weld cracking problems. (see Cl. 10.9)

10 WELDING OPERATIONS AND THE PRECAUTIONARY MEASURES

10.1 Weld Procedures and Welders should be qualified to the relevant code, such as API 1104, API 1107 or ASME Section IX. Test certificates for each batch of electrodes and other welding materials shall be verified for the adequacy.

10.2 The section of pipeline, on which hot tapping is to be installed, shall be checked for roundness after it has been cleaned thoroughly. The external condition of the pipe shall be examined for corrosion.

10.3 An ultrasonic examination shall be performed on the pipeline section to be covered under hot tap fitting, with 250 mm additional width on either side. It establishes actual wall thickness and condition of the pipe with respect to defects, if any. 10.4 The weld edge areas of the fittings shall be thoroughly cleaned. In case of spiral or seam welded pipes, the welded seams are to be ground flush to ensure the correct fit up. 10.4.1 The safe internal pressure of the new pipeline is to be reduced as per 10.18.5. 10.5 In high moisture areas, surface of the pipe shall be preheated to eliminate the moisture, prior to the installation of fitting. 10.6 Rest the top (Branch Half) of the fitting on the pipe, with the backing strips (if required) inserted in place. Then position the bottom half of the fitting, and using an adequate clamp. 10.7 With respect to ambient and pipeline line temperature due to gas flow, resulting in cooling of the pipeline during welding, consideration should be given for establishing the welding cycle available. This may be done by preheating the fitting /line to the upper pre heat temperature limit as prescribed by the welding procedure and then timing the temperature decay to the lower specified pre-heat temperature limit. 10.8 Welding electrodes recommended for this operation are 3.25mm (0.125”) low Hydrogen AWS-E-XX16 or AWS-E-XX18 Pipe electrodes as per ASME Section II C, for the first three passes on the longitudinal seams and for the circumferential fillet welds. [In the case of fillet welds that exceed 12.5mm throat depth, 4mm (5/32”) electrodes may be used after deposition of the first layer with 3.25mm (1/8”) electrodes]. 4mm (5/32”) electrodes are normally used for all subsequent passes after the first three on the longitudinal welds.

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10.9 Appropriate backing strip of suitable material may be provided. If required, tack weld with due pre-heating, at the four corners of the longitudinal seams, each tack being not less than 50.0mm (2”) using qualified procedure. Similar tack welds can be provided in the centre of longitudinal seams if required. Under no circumstances the tack welds should be provided under stressed condition. The end of these tack welds should be ground thoroughly to ensure that no crack exists at the end prior to welding. On no account should the tack, or any portion of the longitudinal weld come into contact with the pipe. 10.10 After positioning of the fitting by tack welding, prepare both ends of the tack welds by grinding. Pre-heat the fitting, if required, to the requisite temperature, then commence welding of the longitudinal seams as described (in Cl.10.7 & 10.8) above, i.e., 3.25mm (1/8”) electrodes for the first three passes, then 4mm (5/32”) electrodes for all subsequent passes until completion, ensuring that welding is carried out diagonally in opposition to disburse weld stresses uniformly and to minimize the deformation. The circumferential seams shall also be invariably welded using two welders diagonally opposite; in case encirclement diameter is more than 12”. 10.11 On completion of longitudinal welds and circumferential welds, giving consideration to pre-heat and using 3.25 electrodes, complete the fillet welds. [Refer Cl. 10.7 & 10.8]. It is followed by welding of a number of buttering layers to the pipe wall, but not in contact with the fitting. The following run is then applied to the ‘throat’ of the tee, between the tee and the innermost buttering run. The remaining weld sequence is then to fill the rest of the fillet. The normal fillet size (leg length) deposited is between 1 and 2 times the wall thickness of main line pipe. 10.12 The second circumferential weld is now performed as above (Cl 10.11), ensuring that the first circumferential weld is cooled to ambient temperature before the second circumferential is started. 10.13 All welds are finally checked for integrity using either dye or magnetic particle inspection techniques. 10.14 Temperature indicating crayons or a contact pyrometer are normally used to ensure correct preheat temperatures. In addition, a visual inspection is carried out for cracks, lack of fusion, undercuts and general weld quality. The hardness of a weld has been found to be a good indication of weld cracking probability. A Brinell hardness of 215 BHM, maximum, is recommended for the circumferential and longitudinal field welds. Grinding of the cap may be required to achieve an accurate hardness reading. Welds over 215 BHN indicate more extensive inspection to be carried out, than normally warranted. 10.15 The fitting is hydrostatically pressure tested after attaching to the line. Care shall be taken to ensure that the collapse pressure of the pipe has not exceeded. Recommendations regarding hydrostatic test pressures are that of the actual line pressure plus 10 percent be used.

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11 RECOMMENDATIONS BEFORE WELDING ON LIVE PRODUCT LINES 11.1 In order to establish the parameters for pipeline wall thickness and internal line pressure, a simple formula based upon the calculations as to the yield stress of the pipeline may be used. 11.2 It is necessary to ascertain that the flow condition exists within a line and there is sufficient heat dissipation volume within a vessel. In addition it is recommended that any vessel should be equipped with either an “open flow” system, or some pressure relief device. 11.3 In order to establish basic welding parameters there may be a need to pre-heat the proposed weld area. This pre-heat may be to up to maximum weld temperature, and then cooling rates are timed to minimum weld temperature. With this information, the welder will be aware as to the time available for him for individual passes. If necessary, adjustments may be made to the line flow rate to bring the cooling rate to within acceptable parameters. 11.4 It is necessary to define rod sizes for relevant fillet welding, and any buttering runs that are applied to the line prior to nozzle attachment /full encirclement fitting circumferential attachment welds. Experience has shown that a nominal rod of the same type, if applied to a correct and acceptable welding procedure, will provide a weld pool of nominal 3mm depth by 4mm diameter. 11.5 It is now necessary to define the degree of strength remaining in the pipe during the welding process. The formula used for defining the percentage of the degree of strength is: Percentage of degree of strength = 100PD 20ST

Where P= Line Pressure in Bar

D= Line OD in mm 20= Metric Coefficient S= SMYS in N/mm2 T= Wall Thickness in mm In the case of ‘T’ the figure of Wall Thickness minus Weld Pool depth is indicated.

11.6 Safe internal pressure inside the pipeline, during the welding operation , can also be calculated by

P = 2 X S ( t – c) X 0.72 / D Where: P : Max. Allowable pressure to be maintained inside the pipeline during Welding (in psi.). S : Specified minimum yield strength, psi. t : Nominal Pipe wall thickness in inch. D : Nominal Pipe diameter in inch. c : Correction factor (3/32”), Allowance for heat metal loss of strength.

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12 INSPECTION AND TESTING

12.1 The surface of the main pipeline on which split tee/fitting is to be welded shall be ultrasonically tested to avoid welding on defective area. Magnetic particle/ Dye penetrant inspection shall be performed for the first pass and after completion of all welds. 12.2 Before cutting operation, the assembly shall be hydrostatically pressure tested to a pressure not exceeding the internal pressure in the run pipe. The test pressure shall be maintained for a minimum period of one hour. All welds found to be defective by hydrostatic testing or by NDT shall be repaired or cut and re-welded and re-tested. Repair of a repaired weld is not permitted. 13. MAINTENANCE Maintenance of all equipments shall be carried according to OEM guide line & following records may be kept. Maintenance through PM module of ERP gives an added advantage for scheduling and cost monitoring. The following is an informative Annex.

SSaammppllee (Name of Pipeline Network) Maintenance of Hot Tapping Machine & Accessories O&M Base : ( Name) Format No. : 01 Equipment Name: ( Hot tapping machine model) Date : Job Card No Dated: Man Days:- RH: Sl.No Activities(QMS) Frequency Observation Action Remarks 1 Operate manually M 2 Operate with power system M 3 Check for any oil leakage M 4 Check oil pressure(record the pr.) M 5 Check the gear oil & replace, if required Q 6 Lubricate the drive tube. M 7 Observer for abnormal sound M 8 Coat the boring ban with light oil. M LIST HERE-UNDER ANY EXTRA WORK PERFORMED OR WHICH MAY WARRANT ATTENTION IN FUTURE : SPARES / CONSUMABLES USED Sr. No. ITEM NAME PART NO. CODE NO. QUANTITY REMARKS Sr. No. Parameters (EMS) Measurable Observation

1 Lube Oil. Sr. No. Parameters(OHSAS) Safety adopted Observation

1 Lubricate Handling Remarks : Review Remarks: Reviewed By: Inspected By : Name: Name : Designation : Designation :

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SSaammppllee (Name of Pipeline Network) Maintenance of Hot Tapping Machine & Accessories O&M Base : ( Name) Format No. : 02 Equipment Name: (Model & Sr No of Drilling machine) Date : Job Card No: Dated: Man Days:- RH: Sl.No Activities(QMS) Frequency Observation Action Remarks 1 Operate manually M 2 Operate with air motor M 3 Check for air pressure M 4 Hydro testing of M/c at 2000Psi Before use 5 Observer for abnormal sound M 6 Clean the boring bar & apply light coat of

lube oil Before & after use

7 Clean the M/c M

LIST HERE-UNDER ANY EXTRA WORK PERFORMED OR WHICH MAY WARRANT ATTENTION IN FUTURE :

SPARES / CONSUMABLES USED Sr. No. ITEM NAME PART NO. CODE NO. QUANTITY REMARKS Sr. No. Parameters (EMS) Measurable Observation

1 Lube Oil. Sr. No. Parameters(OHSAS) Safety adopted Observation

1 Lubricate Handling Remarks : Review Remarks: Reviewed By: Inspected By : Name: Name : Designation : Designation :

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SSaammppllee (Name of Pipeline Network) Maintenance of Plugging Machine O&M Base : (Name) Format No. : 03 Equipment Name: ( Model & Sr No of Plugging machine) Date : Job Card No: Dated: Man Days:- RH: Sl.No Activities(QMS) Frequency Observation Action Remarks 1 Operate with power system M 2 Check for any oil leakage M 3 Check oil pressure(record the pr.) M 4 Check the lock nut of boring bar M 5 Check the functioning of lever/switch M 6 Observer for abnormal sound M 7 Coat the boring bar with light oil. M LIST HERE-UNDER ANY EXTRA WORK PERFORMED OR WHICH MAY WARRANT ATTENTION IN FUTURE : SPARES / CONSUMABLES USED Sr. No. ITEM NAME PART NO. CODE NO. QUANTITY REMARKS Sr. No. Parameters (EMS) Measurable Observation

1 Lube Oil. Sr. No. Parameters(OHSAS) Safety adopted Observation 1 Lubricate Handling Remarks : Review Remarks: Reviewed By: Inspected By : Name: Name : Designation : Designation :

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SSaammppllee (Name of Pipeline Network) Maintenance of Power Unit O&M Base : ( Name ) Format No. : 04 Equipment Name: ( Model & Sr no of Power unit) Date : Job Card No Dated: Man Days:- RH: Sl.No Activities(QMS) Frequency Observation Action Remarks 1 Check the hydraulic oil level & replace,

if required. M

2 Check the diesel level & replace, if required. M

3 Check the engine oil level & replace, if required. M

4 Check for air filter, fuel filter,oil filter & Replace, if required. M

5 Check the SOV M 6 Operate the power unit independently M

7 Operate power unit with Hot Tapping M/c.

M

8 Operate power unit with Plugging m/c M

9 Clean the entire power unit M 10 Observer for abnormal sound M 11 Check the condition of Hydraulic hoses

& NRV’s M LIST HERE-UNDER ANY EXTRA WORK PERFORMED OR WHICH MAY WARRANT ATTENTION IN FUTURE : SPARES / CONSUMABLES USED Sr. No. ITEM NAME PART NO. CODE NO. QUANTITY REMARKS Sr. No. Parameters (EMS) Measurable Observation

1 Lube Oil. Sr. No. Parameters(OHSAS) Safety adopted Observation 1 Lubricate Handling Remarks : Review Remarks: Reviewed By: Inspected By : Name: Name : Designation : Designation :

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SSaammppllee

(Name of Pipeline Network) Maintenance of Sandwich Valve O&M Base : (Name ) Format No. : 05 Equipment Name: ( make & Sr No of Sandwich Valve) Date : Job Card No: Dated: Man Days:- RH: Sl.No Activities(QMS) Frequency Observation Action Remarks 1 Clean the sandwich valve M

2 Lubricate the valve M

3 Operate the valve ( record operation, hard/smooth) M

4 Check all the accessories M

5 Check the fittings & O Ring of Bypass valve M

LIST HERE-UNDER ANY EXTRA WORK PERFORMED OR WHICH MAY WARRANT ATTENTION IN FUTURE : SPARES / CONSUMABLES USED: Sr. No. ITEM NAME PART NO. CODE NO. QUANTITY REMARKS

Sr. No. Parameters (EMS) Measurable Observation

1 Lube Oil. Sr. No. Parameters(OHSAS) Safety adopted Observation

1 Lubricate Handling Remarks : Review Remarks: Reviewed By: Inspected By : Name Name : Designation : Designation :

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Annex- A

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Annex-B

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Annex-C, SUGGESTED HOT TAP CHECKLIST (Cl 1.1)

This checklist is intended to be used as a reminder to accomplish the steps involved in hot tap operations in an orderly manner. Particular circumstances of jobs may dictate additional preparatory steps. This checklist may be retained as a record of the job.

Location _____________________________________________________________

Date ________________________________________________________________

Job _________________________________________________________________

Prepared by __________________________________________________________

C-1 BEFORE STARTING THE HOT TAP

Each of the following considerations should be satisfied before starting the hot tap:

1. Review /follow manufacturer’s instructions.

2. Have the contents of the line or vessel to be hot tapped or welded been assessed, and MSDS’s reviewed for health hazards, to assure procedure is appropriate?

3. It is material in the line or vessels stable under heated conditions.

4. Has the connection been designed per requirements?

5. Do the flanges, bolts, gaskets, pipe and valve to be installed meet the code for the line or vessel to be hot tapped?

6. Has the welding procedure specification been developed as covered in this section.

7. Have approved work permits (Hot Work, Entry, and so forth) been obtained?

8. Review manufacturer’s instructions to ensure that the hot tapping machine has suitable pressure, temperature ratings, and adequate cutter travel for this job.

9. Has the valve been pressure tested and the cover fitted to assure that it will work and fit properly?

10. Has the exact location of the hot tap been identified and marked on the line or equipment?

11. Has the area to be welded been inspected for thickness and freedom from existing welds, laminations, hydrogen attack, or other metallurgical imperfections?

12. If laminations or defects have been found, has a thorough engineering evaluation been made to determine if and how to proceed with the work?

13. Has the metallurgy of the line or vessel been established, and is it compatible with the connecting fitting?

14. Can the area support the weight of the hot tapping machine, and is there adequate hoisting and support for the hot tapping machine and subsequent piping?

15. If PWHT of the welded area is required, was an appropriate review conducted in accordance?

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16. Is there sufficient external clearance to install the hot tapping machine and extract the cutter through the valve?

17. Is there sufficient internal clearance to retract the cutter and coupon through the valve?

18. Is the hot tap fitting of the proper length to accommodate operation of the hot tapping machine?

19. Have oxygen, combustible gas, and toxic atmosphere tests been conducted in the hot tap area?

20. Has a fire watch been assigned and appropriate fire fighting equipment provided?

21. Have all personnel in the area been provided with appropriate personal protective equipment?

22. Is the area to be hot tapped located below the liquid level of the tank, or on a line or vessel in which flow has been established?

23. Is there adequate storage area and room for operational and emergency access?

24. Has a procedure been prepared and in place to isolate the work area in the event of a failure? Are personnel trained to implement the procedure?

25. Have the requirements been defined for weld inspection and for pressure testing, and is all of the testing equipment on hand and in good working condition?

C-2 BEFORE WELDING

Each of the following considerations should be satisfied before welding:

1. Are the welders qualified for the approved welding procedure (specification) to be used?

2. Is a preheat of the weld area required?

3. Is the fitting properly positioned so that misalignment of the hot tapping machine will not occur?

4. Have the pressure and temperature of the contained materials been reduced as much as the process operation will allow?

5. Have the flow, pressure, and level considerations?

C-3 BEFORE CUTTING

Each of the following considerations should be satisfied before cutting:

1. Has the weld been inspected and tested?

2. Has the hot tap fitting been pressure tested?

3. Have the hot tap valve, packing, gasket and bolts been checked for leakage?

4. Have the packing or seals on the hot tapping machine been checked?

5. Has the bleed off valve been checked to assure it will hold, is operable and is not obstructed?

6. Are all bolts on the pilot and cutter bit tight?

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7. Is the coupon catcher on the pilot bit?

8. Is the valve centered on the flange?

9. Has cutting depth been calculated to avoid cutting the opposite side of the pipe?

10. Has the boring bar been run through the valve to assure free passage?

11. Have the hot tapping machine and valve been purged, if recommended?

C-4 BEFORE REMOVING THE HOT TAPPING MACHINE

Each of the following considerations should be satisfied before removing the hot tapping machine:

1. Have the manufacturer’s instructions been followed to be sure that the boring bar is fully retracted before closing the hot tap valve?

2. Has the hot tap valve been closed?

3. Has the bleeder valve been opened?

4. Has all of the pressure been bled off of the hot tapping machine before removing the bolts from the flange?

5. Have provisions been made to contain or control any liquid or gas in the hot tapping machine?

C-5 AFTER REMOVING THE HOT TAPPING MACHINE

1. The hot tap machine should be cleaned, removing the hydrocarbons /chemicals from the line or equipment.

2. All rags, absorbent pads and other cleaning materials must be disposed off properly.

C-6 BEFORE STARTING THE PLUGGING OPERATION

Each of the following consideration should be satisfied before staring the plugging operation.

1. Review /follow manufacturer’s instructions.

2. Has the bypass line of the pipeline section to be isolated been installed and operational?

3. Have approved work permits (Hot Work, Entry, and so forth) been obtained?

4. Review manufacturer’s instructions to ensure that plugging tapping machine has suitable pressure, temperature ratings, and adequate control bar travel for this job.

5. Has a procedure been prepared and in place to isolate the work area in the event of a failure? Are personnel trained to implement the procedure?

6. Has the sealing element been checked with respect to its manufacturing date and sized as per ID of the pipeline for maximum pressure retention?

7. Does the bar lock clamp position (open/close) being set as per requirement?

8. Has the bladder valve for purging and equalization line use to equalize the pressure across the plugging head been installed?

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9. Check the pressure gauge installed on plugging head housing.

10. Has all the measurement been taken for lowering the plugging head with sealing element inside the pipe?

11. Inspect the plugging head component and perform maintenance if required.

12. For installing the sealing element on plugging head has the torque to all bolts being maintained as per recommendation.

13. Has the orientation of plugging head, while installing on the control valve been ensured as per the requirement?

14. The lip of sealing element coated with heavy grease or not.

15. Has it been ensured that only new sealing element is used?

16. After installing the plugging machine on sandwich valve ensure the connection of hydraulic hoses with power unit.

17. It is to be ensured that first the plugging head set at the downstream side then upstream side.

18. Confirm Bar lock clamp engaged after setting of the plugging head.

C-7 CUTTING OF THE PIPELINE SECTION

Each of the following consideration should be satisfied before staring the operation of cutting of pipeline section

1. Confirm the isolated section vented /drained completely.

2. Ensure the sealing element holds properly and there is no passing of the product.

3. Use cold cutting machine for cutting the pipeline section.

4. Before welding the new /modified section ensure the LEL level again.

C-8 REMOVAL OF THE PLUGGING HEAD

Each of the following consideration should be satisfied before staring the operation of removal of the plugging head

1. Has the pressure been equalized across the plugging head?

2. Has the bar lock clamp been disengaged?

3. Ensure the retraction of control bar very slowly.

4. Has the retraction is being done first to the upstream.

5. After retracting the control bar are the sandwich valve closed.

6. Has the removal of hydraulic hoses and venting of the product from plugging machine being ensured before removal of the plugging machine?

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C-9 SETTING OF THE COMPLETION PLUG AND RETRIVAL OF THE SANDWICH VALVE

Each of the following consideration should be satisfied before staring the setting of the completion plug

1. Has the o-ring groove and segment groove inspected and necessary maintenance done?

2. Has the performance of check valve in completion plug checked?

3. Has the coupon welded on the scarfed nipple in proper orientation?

4. Have the edges of the coupon grinded as per the recommendation?

5. Has the measurement for setting the completion plug been taken?

6. Pressure equalization channel in plug holder and ball check valve and seat for ball check valve in completion plug cleaned and free of dirt or ice or other depreciation.

7. After installing the machine on sandwich valve has it been confirmed that equalization line installed with pressure gauge and the pressure gauge is calibrated or not?

8. Before proceeding for setting the completion plug has it been ensured that the pressure of the product above and below the plug remains equalized.

9. Before realizing the plug holder from boring bar has it been ensured that the two segments matched properly and locks are put in their place to hold the completion plug?

10. Has it been ensured that before removing the hot tapping machine the boring bar retracted and the product has been removed from the machine?