CONSTRUCTION SPECIFICATION PIPING CONSTRUCTION WORKS...

< Security Level 2 > Sheet 1 of 39

CONSTRUCTION SPECIFICATION

PIPING CONSTRUCTION WORKS

FOR

NITROGEN PACKAGE

FOR

HINDUSTAN PETROLEUM CORPORATION LTD.

VISAKH REFINERY

DHT PROJECT

TEIL JOB NO. : 6261 DOCUMENT NO. : H - 301

A 16.04.2009 For Bid Enquiry UCM PRK SSV

Rev. no. Issue Date Description Prepared by Checked by Approved by

TOYO ENGINEERING INDIA LIMITED MUMBAI INDIA

< Security Level 2 > Sheet 2 of 39

Revision History

Rev. Date Description A 16.04.2009 For Bid Enquiry

< Security Level 2 >

HPCL, Visakh


ISSUED : 29.12.2008 JOB NO. : 6261

TOYO ENGINEERING INDIA LTD.

DOC.No. H – 301 DHT PROJECT Sheet 3 of 39

CONTENTS PAGE NO1 General ........................................................................................... 4 1.1 Scope .............................................................................................. 4 1.2 Specific Job Requirements ............................................................. 4 1.3 Codes and Standards ..................................................................... 4 1.4 Related Engineering Specifications ................................................ 4 1.5 Units ............................................................................................... 4 2 General Requirement ..................................................................... 5 2.1 Qualification .................................................................................... 5 2.2 Material ........................................................................................... 5 2.3 Drawing and Document ................................................................... 5 3 Fabrication ..................................................................................... 6 3.1 General ........................................................................................... 6 3.2 Cutting ............................................................................................. 6 3.3 End Preparation .............................................................................. 7 3.4 Alignment and Trimming ................................................................. 7 3.5 Preheat and Interpass temperature..................……....................... 11 3.6 General Requirement for Welding .................................................. 12 3.7 Welding Rods ................................................................................. 13 3.8 Welding .......................................................................................... 13 3.9 Heat Treatment .............................................................................. 18 3.10 Bending .......................................................................................... 24 3.11 Marking .......................................................................................... 24 3.12 Storing ............................................................................................ 24 4 Assembling and Erection ................................................................. 25 4.1 General ............................................................................................ 25 4.2 Flanged Joint .................................................................................... 26 4.3 Threaded Joint ................................................................................. 26 4.4 Mechanical Joint ............................................................................... 27 4.5 Tubing Joint ...................................................................................... 27

5 Other Piping System ……………………………………………………. 27 5.1 General …………………………………………………………………… 27 5.2 Under Ground Piping……………………………………………………. 27 5.3 Jacketed Piping…………………………………………………………. 29 5.4 Steam Trace Piping……………………………………………………… 30

6 Inspection, Examination and Testing ............................................. 31 6.1 Extent of Inspection, Examination and Testing .............................. 31 6.2 Non-Destructive Examination ........................................................ 36

7 Cleaning after Piping Assembling and Election .............................. 39


HPCL, Visakh


ISSUED : 29.12.2008 JOB NO. : 6261 TOYO ENGINEERING INDIA LTD.

DOC.No. H – 301 DHT PROJECT Sheet 4 of 39 1 GENERAL 1.1 Scope

This specification covers the general requirements for the piping construction works including test and inspection, covered under Nitrogen Package for Diesel Hydrotreater Project for HPCL’s Visakh Refinery at Andhra Pradesh, Hindustan Petroleum Corporation Limited (HPCL), has appointed Toyo Engineering India Ltd as “Project Management Consultant “ (PMC).

1.2 Specific Job Requirements

Where Specific Job Requirements are in contradiction to this specification, Specific Job Requirements shall govern.

1.3 Codes and Standards

International codes and standards supplementary in related to this specification shall be as follows:

(1) ANSI /ASME B31.3 Chemical Plant and Petroleum Refinery Piping (2) ANSI/ASME B1.20.1 Pipe Threads, General purpose (inch) (3) ASME/ANSI B16.5 Pipe Flanges and Flanged Fittings (4) ASME Boiler and Pressure Vessel Code Section VIII, Section V. (5) Indian Boiler Regulation (IBR).

1.4 Related Engineering Specifications

The related Engineering Specification to supplement this specification is as follows: (1) H-103 Piping Materials (2) H-106 Marking of Piping Materials (3) H-109 Pipe Supports (4) H-315 Cleaning of Piping (5) H-317 Leak Test (6) H-321 Welders Qualification Test (7) H-331 Welding Procedure Qualification Test

1.5 Units

The SI unit shall be applied as the measurement system for documents and drawings. Nominal size of piping components shall be measured in Inches, for which the abbreviation is NPS. Nominal flanges rating shall be as per the applied codes and standards.


HPCL, Visakh



DOC.No. H – 301 DHT PROJECT Sheet 5 of 39 2. GENERAL REQUIREMENT 2.1 Qualification

(1) Persons who are engaged for welding work including tack welding and

support welding shall have passed the PMC qualification test stipulated in Engineering Specification H-321

(2) Welding Procedure Specification and the Procedure Qualification

Record as per Engineering Specification H-331 shall be obtained for welding work.

(3) Persons who are engaged for pipe fitting, assembling, and erection

work, using temperature indication crayon for the heat treatment etc. shall be fully trained and shall have the qualification of Employer. License, certificate, pass or qualification issued from Authorities, if available, shall be effective.

(4) The inspector nominated for the job, must be a specialist or an expert

in respective examinations and licensed or qualified by an internationally recognized Association and / or by any statutory regulation as applicable.

2.2 Material 2.2.1 Piping Materials shall be in accordance with Engineering Specification H-103.

2.2.2 It is applicable to use other alternate materials, which have been approved by

PMC based on the Engineering Specification H-103.

2.2.3 Selection of welding rod shall be in accordance with Par. 3.7 in this Engineering Specification.

2.2.4 Quality certificate of technical gas to be used for the work such as argon gas,

propane gas, etc. shall be provided with approval of PMC before work starts. 2.3 Drawing and Document

2.3.1 Drawing and document, which cover the piping construction work, shall be issued by PMC in accordance with “Drawing and Document List”.

2.3.2 Piping work shall be carried out with PMC issued “Final” drawing and document

unless otherwise specified.


HPCL, Visakh



DOC.No. H – 301 DHT PROJECT Sheet 6 of 39 3. FABRICATION 3.1 General 3.1.1 Fabrication requirement shall be in accordance with ASME B 31.3 unless

otherwise specified. 3.1.2 Fabrication shall be executed in accordance with the drawings, documents and

the related Engineering Specifications stated in Par. 1.4 and 2.3 of this Specification.

3.1.3 Stainless steel pre-fabrication work including material storing shall be well

separated from other steel pre-fabrication works. Tools and equipment to be used shall be suitable for stainless steel and shall not be used on any other materials, or vice versa.

3.1.4 The bolt holes of flanges shall be straddle /off centre from a vertical center line

in a horizontal pipe line, and from plant north on a vertical pipe line unless otherwise indicated in the drawing.

3.1.5 Marking of piping materials shall be in accordance with Engineering

Specification H-106. 3.2 Cutting 3.2.1 Cutting line shall be marked on pipe. Where the material marking will become

invisible after cutting, additional material marking shall be provided. 3.2.2 In the case of gas cutting, cutting surface shall be ground off to remove any

edge and roughness and be made flush and smooth so as not to harm welding quality. In the case of automatic or semi-automatic gas cutter, the cut edge may be beveled without such grinding off.

3.2.3 In the case of gas cutting, cutting slag stuck inside pipe shall be completely

removed, especially for boring of pipe for weld branch. 3.2.4 Abrasive disc used for cutting or grinding of austenitic stainless steels or other

high Cr-Ni steel shall not be used for carbon steels, or vise versa. 3.2.5 Plasma jet cutting may be applied for cutting stainless steel materials.


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DOC.No. H – 301 DHT PROJECT Sheet 7 of 39 3.3 End Preparation 3.3.1 End preparation for butt weld shall be in accordance with Table 3.3.1, or any

other details which meets the WPS,

(1) Welding Bevels for Butt Welds Table 3.3.1

T

Thickness of Pipe Type of End Shape of Groove

37. + 0

1. +

t

1 + 0

1. +

37. + 0

1 + t

I

V

Double - V

t < 3

t < 22

t > 22


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(2) Shape of beveling other than mentioned in Table 3.3.1 shall be in accordance with the WPS approved by PMC.

(3) All weld bevels and weld surfaces shall be free from cracks, porosity,

slag inclusion and other defects indicative of poor manufacture. 3.4 Alignment and Trimming 3.4.1 Root gap for butt-weld shall be in accordance with the WPS. 3.4.2 In the case of butt welding pipe and / or fitting having unequal wall thickness, of

which the difference is more than 3 mm in outer surface and / or 1.5 mm in inner surface, the end of the thicker pipe shall be trimmed by grinding as per the Fig. 3.4.2 (a), (b) and (c) shown below. The gradient of this trimming shall be less than 30° between worked and nonworked parts shown as below.

Max 30 03.0 or Over

> t m

(a)

Max 30 01.5 or Over

> t m

(b)

Fig 3.4.2

1.5 or OverMax 30 0

In case ultrasonictest to be applied

> t m t m or Over

(c)

Remark: t m is required minimum wall thickness

Note: In the case that “Special End Detail” is specified in the Specification H-103 for the pipe and / or fitting of which the nominal wall thickness is 30 mm and over, the end preparation shall be in accordance with such provision.


HPCL, Visakh




3.4.3 Branch connections which about the outside surface of the run pipe shall be contoured for groove welds which meet the WPS requirements [see Fig. 3.4.3 (a) and (b)].

Branch connection which are inserted through a run opening shall be inserted

at least as far as the inside surface of the run pipe at all points [see Fig. 3.4.3 (c)].

g

m

(b)

Tb

0mm ~ 3mm

g(c)

Tb

g = Root gap per WPSm = The lesser of 3.2mm or 0.5 Tb

g m

(a)

Tb

Fig 3.4.3

3.4.4 When a pipe having a longitudinal weld seam is used in a horizontal line, the pipe shall be laid so that the longitudinal weld seam is not on bottom or top of the pipe. Allocation and relation among circumferential longitudinal and other (branch, support, etc.) welds are shown in the Fig. 3.4.4 (a), (b) or (c).

Remarks : L1 shall be five times the pipe thickness or over.

Fig : 3.4.4 (a)

L1

L1

1.00

(1) Circumferential joint


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(2) Branch pipe and weld line on run pipe

Fig. 3.4.4 (b)

L

L1

L

Remarks: 1. L and L1 show the distance between both toes of the bead. 2. L shall be three times the pipe thickness or over. 3. L1 shall be five times the pipe thickness or over.

Fig: 3.4.4 (c)

WELDING SHOE Remark: L shall be minimum 6 mm.

LL

When a support iswelded to a bend or pipethe weld shall not crossthe weld of the bend orpipe. Both sides shallbe roundly welded.

"A"

"A"L L

WELDING SUPPORT

Detail "A'

(3) Support / Shoe and weld seam of main pipe


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3.4.5 Each butt, socket and support joints shall bear an identification number, which shall be maintained in the piping sketch/ drawing. These numbers shall appear on the fit up/ weld visual reports and NDT records.

3.5 Preheat and Interpass temperature 3.5.1 Preheating shall be performed by propane flame or by any another appropriate

method prior to commencement of welding including tack welding. Any flame heating shall be applied as evenly all round as possible, avoiding hot spots.

3.5.2 Materials and preheating temperature shall be, unless otherwise specified, as

Table 3.5.2. The thickness in Table 3.5.2 is that of the thicker component measured at the joint.

Table 3.5.2

Material specification

P-No. ASTM NPS Thickness

t(mm)

Temperature

(0C)

1

A 120 A PI5L Gr. A A 53 Gr. A/B

all t < 25 not required * Note 1

A 106 Gr. A/B A 333 Gr. 1 A 524 Gr. I/II A 515 Gr. 60

all t ≥ 25 80 and above

3 A 333 Gr. P1 A 204 Gr. A/B

all t ≥ 12.7 80 and above

4 A 335 Gr. P12 A 335 Gr. P11

all all 180 and above

5 A 335 Gr. P22 A 335 Gr. P5 A 335 Gr. P9

all all 180 and above

8 A 312 Gr. TP 304 A 312 Gr. TP304L A 312 Gr. TP316 A 312 Gr. TP316L

all all not required * Note 1

9 A 333 Gr.3 all all 100 and above

Note 1 In a case where the ambient temperature is below 50C, preheating to a temperature 400C minimum shall be applied to P-1 and P-8.


HPCL, Visakh




Remarks: 1.Temperature shall be measured by surface thermometer or

temperature indicating crayons.

2. Inter-layer weld temperatures shall be kept the same as preheat temperatures until the welding is finished.

3. When welding dissimilar metals, preheat temperature shall be in

accordance with WPS, notwithstanding the provisions above.

3.5.3 The preheat zone shall extend at least 25 mm beyond each edge of the weld. 3.5.4 Welding work shall be continuous. If interruption is unavoidable, measures to

avoid sudden cooling shall be taken and reheating shall be carried out before starting to welding again, in accordance with Table 3.5.2.

3.5.5 During welding care should be taken to avoid any kind of movement of

components, shocks, vibration and stresses to prevent occurrence of weld cracks.

3.6 General Requirement for Welding 3.6.1 Requirement and criteria for welding shall be as follows, unless otherwise

specified in the drawings:

(1) Welding shall be performed in accordance with WPS. (2) Complete back-shielding with Argon gas shall be required during the

welding of the root pass for A 335 Gr.P5 and over, stainless steel, High-Ni alloy, Ti etc. in accordance with WPS.

(3) Welding shall not be carried out in adverse weather conditions where there is impingement of rain, snow, sleet storm or excessive wind at the working area, unless appropriate and adequate protection is provided.

(4) The bevel shall be fully cleaned so that there is not rust, oil, paint, sand, moisture, etc. remaining. Care shall be taken that the stainless steel does not come into contact with any form of zinc based material. Where a bevel is not to be welded immediately it shall be protected to prevent contamination.

(5) Spatter, slag, etc. on the weld or in the heat-affected zone, shall be thoroughly removed to the metal surface.

(6) Arc strikes on base metal shall be avoided at all times. Arc strike shall be ground flush and liquid penetrant tested. Any defect shall be ground out and weld repaired.

(7) Material of wire brush shall be properly selected for working carbon steel and stainless steel respectively. They shall always be kept separate and never used on anything other than the designation.


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(8) Welding and heat treatment (preheating, postheating, and stress relieving) for a welded joint valve shall be carried out with the valve opened.

(9) Weld internal protrusion at the weld neck joint of an orifice flange, shall be removed flush and smooth with a grinder. Any concavity in the root shall be weld repaired and ground flush and smooth.

(10) Socket welding shall be performed at least 2 layers weld and end point of weld at each layer shall be changed.

(11) Welding of dissimilar metals shall be carried out at fabrication shop if possible.

3.7 Welding Rods

3.7.1 Selection of welding rods to be in accordance with H-331. 3.7.2 Brand name of welding rod to be used at shop and site shall be approved by

PMC before work starts. Batch analysis certificate of each batch of welding rods shall be submitted to PMC prior to commencement of welding.

3.7.3 Tungston electrodes shall confirm to SFA 5.12 specification. 3.8 Welding

3.8.1 Tack welding shall be carried out as follows:

(1) Both root and bridge tack welding method may be applied.

(2) Avoid wrong fit-up, which would cause residual stress.

(3) Keep the correct root gap by using spacers according to WPS.

(4) Welding condition of tack welding shall be in accordance with WPS.

(5) Provide sufficient external pipe clamps or internal spiders for setting up.

(6) Ensure the contact surface of the clamps or spiders are made of the same base metal, or an inert compound.

(7) Clamps used for fitups shall never be hammered off. Clamps /Bridge

tacks shall be removed by grinding or gas cutting. Gas cutting shall only be performed at the upper part of the weld toe and flush surface of base metal by grinding, and then a liquid penetrant examination shall be carried out. Any defect shall be ground out and weld repaired.

(8) Tack welding or temporary welding of jigs, etc. shall be in strict

compliance with Par. 3.5.2 for applications of preheat temperature.


HPCL, Visakh



DOC.No. H – 301 DHT PROJECT Sheet 14 of 39 3.8.2 Butt joint welding of pipes shall be performed as follows:

(1) Welding shall be performed in accordance with WPS.

(2) Circumferential butt-welding shall be performed without the use of a

backing ring unless specified in WPS. (3) Before welding of the root, both ends of the root tack weld bead shall be

prepared with a grinder as shown in the following illustration in order to make complete fusion.

Fig. 3.8.2

finish into this shapewith grinder

shape before grinding


HPCL, Visakh



DOC.No. H – 301 DHT PROJECT Sheet 15 of 39 3.8.3 Branch connections shall be made by using the fittings as specified in the

Engineering Specification H-103. However, where the branch is to be welded directly to the main run in

accordance with Engineering Specification H-103 or Piping Arrangement Drawing, welding shall be performed, unless otherwise specified, shown in following Fig. 3.8.3:


HPCL, Visakh




tc

Tb

Th

> 450

(1)

*

Th*

tc

> 450

Tb(2)

tc

TrTh

*

(4)Tb

0.5 Tr

2

1

3 -5 φ vent hole

The surface of the weld metal shall befinished flush by grinding or drilling

*

Tm

Th

(5) outlet

`

1.6 - 3.2

45090

350

Tb

Th

Branch Pipe Size

< 11/2 NPS

> 3mm

> 2 NPS

> 6mm

TmNote : * Specified as per WPS

Fig. 3.8.3

tc

Tr

Th

0.5 Tr

3 -5 φ vent hole

*

Tb(3)

2

1


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DOC.No. H – 301 DHT PROJECT Sheet 17 of 39 Remarks: 1. Throat thickness “tc” shall be of 0.7 Tb (minimum 6.4 mm). 2. The symbols used in these figures are as follows: - h: nominal thickness of run pipe. - b: nominal thickness of branch pipe - r: nominal thickness of reinforcement pad 3. At first, weld part and prepare the weld surface with a grinder, then

weld the part . 4. Where reinforcement is necessary, it is indicated in the Piping

Arrangement Drawing and Notes for Piping Drawings.

3.8.4 Fillet welding of pipe to slip-on and socket weld flanges shall be performed as shown in following Fig. 3.8. 4.:

3.0

T

1.4 T min.1.4 T min.

T

(a) Slip - on

T

Fig 3.8.4

Any weld metal into the bore of the pipe shall be removed bygrinding or filling to make it flush with the inside diameter

t

1.6 - 3.2

1.4 T min.

1.4 T min.

Concentrically set

(c) Socket Weld

T

90

REMARKS : 1. T = thickness of pipe t = thickness of flange hub2. If 1.4 T is larger than t, t shall be taken

1.4 T min.

1.4 T min.

t

T3.0

(b) Slip - on

T

90


HPCL, Visakh



DOC.No. H – 301 DHT PROJECT Sheet 18 of 39 3.8.5 Socket welding of pipe components other than flanges shall be performed as

shown in following Fig. 3.8.5: Butt joint shall be completed with a cover layer that would affect good fusion at the joint edges and a gradual notch free surface and shall have a workman like finish.

Fig: 3.8.5

Cx

Cx

1.6 - 3.2

T

Cx (min) = 1.25 T but notLess than 3.2 mm

T = nominal wall thicknessUnit : mm

3.8.6 Weld identification number shall be marked clearly at each joint just adjacent to

the weld.

3.9 Heat Treatment 3.9.1 Postheating shall be applied after the welding was completed as per the Table

3.9.1 and heating shall be performed by propane flame or another appropriate method to all parts of the bead uniformly and a thermal blanket shall completely cover it, to ensure a slow rate of cooling.

Table 3.9.1

P-No. ASME Application thickness t(mm)

Postheating temp (0C)

P-3 A 204 Gr. A/B A 335 Gr. P1

t ≥ 12.7

P-4 A 335 Gr. P12 A 335 Gr. P11

All thickness

300-400

P-5 A 335 Gr. P22 A 335 Gr. P5 A 335 Gr. P9


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Remarks : 1. Temperature shall be measured by surface thermometer or temperature

indicating. 2. When welding dissimilar metals, post heating shall be performed in

accordance with WPS. 3. Postheating may not be required in case of the following:

(1) Welding shall be done by GTAW only. (2) Temperature of weld seam shall be kept at 150° C and over without

cooling down before Postweld heat Treatment. 3.9.2 Postweld Heat Treatment (hereinafter referred to as PWHT) shall be

performed as required for the material groupings and thickness ranges in accordance with Table 3.9.3. Notwithstanding the provision above, PWHT shall be required for all the welds and all the welds and all the thickness where service fluid may cause stress corrosion cracking.

Table 3.9.3 P-

No. ASTM Material Nomin

al Pipe size

(NPS)

Nominal Wall

Thickness(1)

Temp (0C)

Holding Period

at Temp.

(h)

Min. Holding Period

Max. Heating

Rate (oC/h) Rh

Max. Cooling Rate (oC/h)

Rc

1 A 120 A PI5L Gr. A A 53 Gr. A/B A 524 Gr. I/II A 106 Gr. A/B A 333 Gr.1 A 106 Gr. C

All > 19 MM (In case of Category-D Fluid) (>38mm)

593-649

T/25x 1.0 T:Nominal Wall Thickness (mm)

1.0 Rh < 220 x 25/T Max. 220 0C/h Min. 55 0C/h

Rc<280 x 25/T Max. 280 0C/h Min. 55 0C/h

3 A 204 Gr. A/B A 335 Gr. P1

All > 19 mm 593-718

1.0

4 A 335 Gr. P12 A 335 Gr. P11

All > 12.7 mm 704-746

2.0

5 A 335 Gr. P22 All > 12.7 mm 704-760

A 335 Gr. P5 A 335 Gr. P9

All

8 High Alloy Steels Austenitic Stainless steel

All None None None None

9B A 333 Gr. 3 All > 19 mm 593-635

T/25 x 0.5

1.0

Note (1) Thickness of branch connection shall be determined in accordance with par. 3.9.3.


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Remarks: 1. Rate of temperature heating and cooling as shown in the table shall be those at temperature of 3000C or above.

2. The temperature when pipe is put in and taken out of furnace shall not exceed 3000 C.

3. “T” in the table is wall thickness of pipe in mm. 4. For weld joint of pipes having different thickness, the following

thickness shall be taken (a) For butt-welded joint: the thicker thickness (b) For fillet welded joint: the throat thickness

5. In case of weld joint of dissimilar metals, PWHT temperature shall be in accordance with WPS, notwithstanding the provision above.

3.9.3 The thickness to be used in applying PWHT provisions of Table 3.9.3 shall be

that of the thicker component measured at the weld joint, except as follows.

(1) In the case of branch connections, metal (other than weld metal) added as reinforcement, whether an integral part of a branch fitting or attached as a reinforcing pad or saddle, shall not be considered in determining PWHT requirements.

PWHT is required, however, when the thickness through the weld in any plane through the branch is greater than twice the minimum material thickness requiring PWHT, even though the thickness of the components at the joint is less than the minimum thickness. The thickness through the weld specified above shall be computed using the formula corresponding to the details shown in Fig. 3.9.3.

(2) In the case of fillet welds at slip-on and socket welding flanges and

piping connections, and for seal welding of threaded joints in piping, PWHT is required when the base metal thickness at the weld joint is greater than the minimum thickness requiring PWHT in Table 3.9.3, except as follows. (a) Not required for P-No.1 materials when weld throat thickness is

16 mm or less, regardless of base metal thickness. (b) Not required for P-No. 3,4,5 materials when weld throat

thickness is 13 mm or less, regardless of base metal thickness, provided that not less than the recommended preheat is applied, and the specified minimum tensile strength of the base metal is less than 490 Mpa (50 kgf/mm2).

In the case of fillet welds for attachment of external non pressure parts

such as lugs or other pipe supporting elements, PWHT is required when weld throat thickness is greater than the minimum thickness requiring PWHT in Table 3.9.3.


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Th

tc

Tb

Tb + tc (branch pipe thickness + throat thickness)

Th + tc (Main pipe thickness + throat thickness)tc

Tb

Th

> 450

Tb + tc (branch pipe thickness + throat thickness)

or

whichever is greater

tc

Tr

Th

Tb

tc

TrTh

TbTh + Tr + tc(Main pipe thickness + reinforcement padthickness+ throat thickness)

Fig 3.9.3

Tr + tc (reinforcement pad thickness + throat thickness)


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(1)

3.9.4 Postweld Heat Treatment shall be performed in a furnace or by local heating coil as applicable.

3.9.5 Local PWHT with heating coil shall be carried out as follows:

Temperature attained by the portion under heat treatment shall be recorded by means of thermocouple pyrometers. Throughout the cycle of heat treatment the portion outside the heated band shall be suitably insulated so that the temperature at the exposed surface of pipe shall not be allowed to exceed 4000C.

(2) Adequate number of thermocouple pyrometers shall be attached directly at equally spaced locations along the periphery of the pipe joint. The minimum number of thermocouples attached per joint shall be one upto 6” dia, 2 upto 10” dia, and 3 for 12” dia and above.

(3) Temperature-Time chart using automatic temperature recorder alongwith hardness test results shall be submitted for review and approval after the heat treatment is completed. Calibration certificate of each recorder and thermocouples shall be submitted to TEIL prior to commencement of PWHT.

(4) The pipe shall not be in contact with other types of metal during heating. (5) Heating band width for a butt weld shall be a minimum of 25 mm from

each edge of the bead. (6) After heat treatment, cooling in air may be taken place when the

material temperature is 3000C or below. (7) Flanged surfaces shall be completely cleaned after PWHT.

3.9.6 In the case of small pipes of 2 (NPS) or under where the use of a heat coil is

not practical, PWHT may be performed with a local flame heating.

Counting of holding time in post heating or PWHT by local flame heating shall be started after five minutes when specified temperature has been reached.

3.9.7 In the case of the stainless steel weld for A 312 Gr. TP321, of which the metal

skin temperature during operation is expected higher than 470 °C and A 312 Gr. TP347 of which the metal skin temperature is expected higher than 415° C respectively, the heat treatment shall be performed to prevent the stress corrosion cracking caused by Polythionic Acid attack.


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The requirement of the heat treatment shall be as follows,

Temperature Rand (0C) Holding Time (h/in.) Nominal W. Thickness

Min. Holding Time (h)

885 - 900 1.0 0.5

Heating and cooling rate shall be as per Table 3.9.3. 3.10 Bending 3.10.1 The extent and classification of pipe bending shall be in accordance with Table

3.10.1 unless otherwise specified. Table 3.10.1

Type of Piping Material Size (NPS) Type of Bending

Process and Utility Carbon Steel D ≤ 1½ Cold Pressure Piping Stainless Steel D ≤ 1 Cold

3.10.2 Radius of curvature shall be 4 to 6 times of outside diameter of pipes, unless

otherwise specified. 3.10.3 For field fabrication of non-pressure piping, hot bending may be applied

irrespective of Table 5.4.2. 3.11 Marking 3.11.1 All piping components for which welding has been completed shall bear the

paint marking with the joint number and identification number of the welder. 3.11.2 Spool piece No. shall be clearly marked on fabricated components. 3.12 Storing 3.12.1 Inside of fabricated components shall be cleaned by air blowing, then opening

of fabricated components shall be covered with suitable materials so as not to enter the foreign matters such as sand, mud, etc. into piping components. Gasket surface of flange, thread, welding bevel shall be protected from any damage due to cleaning work and handling of storing.

3.12.2 Zinc contamination to stainless and high Ni-Cr steel shall be avoided.

Countermeasures shall be taken to the materials such as protection from Zinc adhesion by paint spray work, separation from Zinc contact when the material is laid on the galvanized grating floor, etc.


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DOC.No. H – 301 DHT PROJECT Sheet 25 of 39 4. ASSEMBLING AND ERECTION 4.1 General 4.1.1 Before assembling of piping, actual tolerance causing from foundation, steel

structure, equipment installation work shall be considered for the piping assembling work.

4.1.2 Excessive stress shall not be allowed to the nozzles of rotating equipments

when the flanges of fabricated component are connected, such work shall be carried out in close supervision of the in-charge of the mechanical work. And openings such as flanged joints of a pump, compressor, etc. shall be kept covered with thin metal plate or other solid blinds with a handle to prevent dust and / or foreign material from entering into the equipments.

4.1.3 If hot work to be performed in the vicinity of instrument control of power cable

duct, an adequate protective cover shall be provided in advance so as not to damage the cables.

4.1.4 When work is carried out in the vicinity of piping made of, or lined with special materials such as plastics, rubber, glass, etc. care shall be taken so as not to damage them.

4.1.5 Valves shall be assembled in clean condition, they shall not be opened during

piping erection except that welding and heat treatment of welded valve joint shall be carried out with valve opened.

4.1.6 If openings are made by cutting the assembled piping and such kind of work is

carried out at assembled place due to the reason of modification, improvement, etc. cut piece and foreign materials shall be removed from inside of piping and it shall be confirmed that the inside of piping is cleaned.

4.1.7 Valves having flow direction shall be installed to conform the flow direction in

accordance with piping drawings. Care shall be taken to the valves in case valve flow direction is reversed against the flow direction of pipe line.

4.1.8 It is prohibited to use small size piping, pumps, instrument etc. as scaffolding

or working stage. 4.1.9 The following requirement shall be observed for piping support.

(1) Pipe supports shall be fabricated and installed in accordance with Pipe hanging Details.

(2) As a rule the location of pipe-supports shall be in accordance with the Piping Arrangement Drawing and Hook-up Drawing.


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(3) The Pre-setting pieces of the pipe hanger shall be removed after completion of leak test of the pipe line. However, pipe lines which will be insulated, it shall be removed after completion of the insulation work.

(4) All shoe support shall be attached to the pipe in accordance with the drawings. It is not permitted to tack-weld a shoe support to the pipe rack, where the shoe support is not to be permanently fixed to the pipe rack.

(5) When supports are installed on building or such kind of structure, permission of installation shall be given by PMC before installation.

4.2 Flanged Joint 4.2.1 Any damage to the gasket seating surface which would prevent gasket seating

shall be repaired, or the flange shall be replaced. 4.2.2 Flanged joints shall be bolted up, after checking the alignment of the flange

centers and the parallelness of flange faces, to ensure that the contact bear uniformally on the gasket. Bolting-up shall ensure that bolt tension is spread uniformly around the flange.

4.2.3 Particular care shall be exercised to ensure that all bolt, nut and gasket are

correctly installed in accordance with the requirements of Engineering Specification H-103.

4.2.4 When assembling flange connections, paste shall be applied to the gasket and

bolts. These prevent seizure of nuts and adherence of gaskets. 4.3 Threaded Joint 4.3.1 The standard to be applied to all threads shall be ANSI/ASME B1.20.1 Pipe

Threads (NPT). 4.3.2 Lubricant shall be removed completely from the thread and inside of pipe after

threading. 4.3.3 In a threaded joint between pipe and flange, the length of thread on the pipe

shall be such that the end of the pipe is short of the gasket surface on the flange by 1.5 to 3.0 mm when screwed-in.

4.3.4 Thread shall be joined with full coupling between straight pipes, and piping shall

have union joints in consideration with repairing at leak test. 4.3.5 Threaded joints shall be sealed with tape or threading compound, unless there

is restriction from process requirement.


HPCL, Visakh



DOC.No. H – 301 DHT PROJECT Sheet 27 of 39 4.3.6 Seal welding of threaded parts, if specified, shall be performed after the part is

screwed-in completely without using paste or oil and fully cleaned, decreased and dried out. Reinforcement of the seal weld bead shall cover completely the remaining thread and must be at least 2-layers weld using a suitable size of electrode.

4.4 Mechanical Joint 4.4.1 Mechanical joint other than flanged joint and threaded joint shall be in

accordance with manufacturer‘s instruction or drawing. 4.4.2 Care shall be taken to avoid distorting the sheet when incorporating such joint

into piping assemblies by welding. 4.5 Tubing Joint 4.5.1 The sealing surface of the flare shall be examined for imperfections before

assembly and any flare of tube having imperfections shall be rejected for flared tubing joints.

4.5.2 Flareless and Compression Tubing Joint shall be performed so that the

compression nut becomes finger tight. 5.0 OTHER PIPING SYSTEM 5.1 General Construction of the following piping systems shall be in accordance with the

following requirements in addition to the relevant section of Sect. 3 and 4 of this engineering specification including, but not limited to, cutting, bending, threading, end preparation, branch connections, preheat application, welding rods, and PWHT

5.2 Underground Piping (if applicable as per scope of work) 5.2.1 Wrapping shall be performed as follows:

(1) Wrapping may be done at manufacturer’s shop or in the field. Particular care shall be exercised at all times during handling and laying, so as to avoid damage.

(2) Coating and wrapping shall be applied to surfaces after they have been

cleaned. The cleaned surface shall be primed as soon as possible after inspection. If the surface is to be left open to atmosphere, then protection from contamination by dust, oil, moisture etc. shall be applied.


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(3) Wrapping and applicable inspection shall be carried out in accordance with

manufacturer’s instruction. (4) A holiday detector shall be used during the coating to ensure the validity of

the application. All defects acquired during transportation or installation shall be repaired, then retested.

(5) All repair work to wrapping shall comply fully with the original installation

requirements.

5.2.2 Excavation shall be performed in accordance with the following requirement:

(1) Execution of works shall be started after pegging out and confirmation for the position of trench to be excavated, referring the appropriate bench marks and ensuring the route is sufficiently clear for safe working.

(2) Before commencing the excavation work, it shall be confirmed that there

is no other buried objects around the place of excavation, and that the location proposed for the excavated soil shall have no bearing load on the excavated trench.

(3) Depth of buried pipes shall be in accordance with the piping drawing.

Excavation work shall be performed considering the safety aspects of the work, especially if the depth of excavation is over 1.5 m in an unbattered trench. The piping work in the excavated trench shall be carried out only after proper protective measures have been taken to prevent the collapse of the excavated trench.

5.2.3 Laying of piping shall be performed as follows:

(1) Before laying pipe is carried out, protective measures to prevent accidents such as trench collapse or landslide, flooding, danger to workers in the area, etc. shall be taken into full consideration.

(2) During laying of piping, full care shall be taken to prevent soil, water,

sand, etc. from flowing into the pipes. Pipes shall be anchored sufficiently to prevent floating due to ground-water or rainwater.

(3) Bedding shall be installed to prevent subsidence or movement of pipes.

Position and method of piping support shall be as indicated in the drawings. (4) Underground pipes equipped with mechanical joints or sockets shall be

sufficiently supported to prevent the pipes from moving out of the position indicated in the drawings.


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5.2.4 To avoid any damage on wrapped surface of the piping, initial back-filling shall

be carried out with small-grain sand, for the part in direct contact with the pipes, as shown in Fig. 5.2.4.

Unit: mm

400 - 500

G.L

100 - 200

50 - 100

not less than 100

filling height with small grain sand

Sleeper (sand bag)

D: outside diameter of underground piping

D

(1) (1)

Room for Welding

φ

(1) : Room for Welding 500 - 600 mm

Fig. 5.2.4

5.2.5 Where road crossings or the similar are specified in the drawings, particular precautions shall be taken to ensure installation, testing, back-fill and compaction are correctly carried out.

5.2.6 Pipeline welds and mechanical joints shall not be placed at road crossing or the

similar. If such condition cannot be avoided, the joint shall be examined prior to back filling by suitable examination.

5.2.7 If leak test for whole piping system at one time can not performed, the system

may be divided into any blocks as block testing. However the joint between block shall be examined by suitable examination method instead of leak test.

5.3 Jacketed Piping


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DOC.No. H – 301 DHT PROJECT Sheet 30 of 39 5.3.1 Assembling of piping shall be performed such that inner pipe of each section

shall be fabricated within proper length for assembling and then outer piping shall be fabricated. Since fabrication of outer pipe must be such that leak test of inner pipe can be performed.

5.3.2 Fabrication of inner pipe shall be made separately within the extent which

allows insertion of outer pipe. Especially in case of three dimensional bent components, separation of outer piping components shall be carefully decided by taking the actual procedure of the work into consideration.

5.3.3 Inner piping shall be leak tested before assembling of outer piping. 5.3.4 Cutting of outer piping or other work which may influence bad effect to inner

piping shall be prohibited after assembling of outer piping has been completed. 5.3.5 Inside of outer piping shall be cleaned before its assembly. 5.4 Steam Trace Piping 5.4.1 Steam trace piping shall be performed in accordance with H-107E. 5.4.2 Hot bending of carbon steel materials may be applicable for steam trace pipe

according to Table 5.4.2.

Table 5.4.2

Type of Piping

Material Size (NPS)

Type of Bending

Temperature (°C)

Cold –

Steam Tracing

Carbon Steel

Pipe

D ≤ 1 1/2

Hot

Heating Temp.: 950 - 1 000 Working Temp.: 750 - 950

Stainless Steel or Copper Tube

– Cold –

5.4.3 Steam trace piping using tubing system shall be referred to Par. 4.5 Tubing

Joint. 6. INSPECTION, EXAMINATION AND TESTING 6.1 Extent of Inspection, Examination and Testing


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Prior, during and after completion of the works, the following examination and test shall be performed:

6.1.1 In-Process Inspection (1) Prior to Commencement of Work

Examination and Testing Acceptance Criterion

(a) Material check To satisfy the requirement of Engineering Specification H-103 and H-106.

(b) Welding Procedure Specification To satisfy the requirement of Engineering Specification H-331.

(c) Welder’s performance qualification Welder’s performance qualification certificate authorized by PMC in accordance with Engineering Specification H-321.

(d) Electrode and welding consumable Material certificate (material name, brand). To satisfy applicable codes and standards.

(2) Prior to Welding


(a) End preparation Shape and dimension To satisfy the requirements of par. 3.4 of this specification.

Cleanliness To be free from paint, oil, rust, scale or other foreign material.

(b) Tack weld Root opening (Gap) To be within the tolerance specified in WPS.

Alignment (Mismatch) Misalignment is not more than 1.5 mm for internal surface and 3.0 mm for outer surface.

(c) Preheating Preheating temperature To keep the Preheating temperature within the tolerance specified in Table 3.5.2 and WPS.

(d) Electrode Drying temperature To be in accordance with manufacturer’s standard.

Drying time To be in accordance with manufacturer’s standard.

(3) During fabrication and assembling


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Dimension (1) See Fig. 6.1.1

Note (1) Flattening ratio and reduction of thickness acceptance criteria shall not be

applied for steam trace piping. It shall be decided in accordance with practical conditions.


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" A "

"A"

" A "

" A "

" A "

" A "

" A "

X X

Rotat ion of f langes f romtheindicated position.Measured asshown1.6 mm maximum

Flattening ratioMax. 8% (internal pressure)

Max . 3% (External pressure)Reduction of Thk.

Max. 10% of the thkickness of pipe at bend part.

End preparation for weld shall not deviate fromindicated position by more than 0.8 mm across theland for gas weld joints or 2.4 mm for other joints

Section X - X

" A "

" A "

NPS TOLARANCE ON " A"

10 and under + 3.2 mm

12 - 36 + 4.8 mm

Over 36 + 4.8 mm

( :- + 1.6 mm for each 12 (NPS) in diameter)

Alignment of facings or ends shall not deviate from the indicatedposition measured across any diameter. More than 1/250 per 300 mm.

Fig : 6.1.1 Application of Pipe Fabrication Tolerances.

α

" A "


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(4) After Welding

Examination and Testing Acceptance criterion

(a) Visual examination of weld

Crack None

Under cut Girth weld and Branch connection

Less than 0.3 mm. But for low temperature service and high temperature service materials, it is not permitted.

overlap (Coldlap) Less than 1.0 mm

Throat thickness of filler weld over 0.9 t (Half/full Cupling) Over 1.0 t (SO/SW Flange) (t : thinner pipe thickness)

Weld reinforcement or internal weld protrusion (root penetration)

Wall thickness 6.0 or under over 6.0 upto 13.0 over 13.0 upto 25.0 over 25.0

Max. (mm) 1.5 3.0 4.0 5.0

Weld scars from jigs and arc strikes

Visual check and no defect. Liquid penetrant examination as per part (b) for high temperature and low temperature service.

Lack of fusion - Girth weld and Branch

connection

Nil

incomplete penetration - Girth weld and Branch

connection

Lesser ≤ 0.8mm or 0.2t, but not more than 38 mm cumulative length in any 150 mm of weld length depth ≤ 0.2t. But for low temperature service and high temperature service materials, it is not permitted.

Surface porosity None


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(b) Heat Treatment - -

Post heating Post weld heat treatment (PWHT)

Temperature and holding time is in accordance with the requirements in Table 3.9.3 and to satisfy it by the chart and record.

Hardness test after PWHT

Note (2)P-No.

Material Brinell Hardness Max. (BHN)

Center of bead (min.2 points)

1 Carbon steel 220

Heat affected zone

3 C-1/2 Mo steel

225

(min.2 points) 4 1.1/4 Cr-1/2 Mo steel

225

5 2.1/4 Cr-1Mo 5Cr-1/2Mo

241

5B 9 Cr.-1 Mo. V - 241

(c) Non-Destructive Examination

Radiographic Examination (RT) As per Par 341.3.2 A of ASME B31.3 and Article 2 of ASME Code Section V.

Liquid Penetrant Examination (PT) As per Par. 341.3.2 A of ASME B 31.3 and Article 6 of ASME Code Section V.

Magnetic Particle Examination (MT)

As per Par. 341.3.2A ASME B 31.3 and Article 7 of ASME Code Section V.

Ultrasonic Examination (UT) As per Par 341.3.2A ASME B31.3 and Article 5 of ASME Code Section V.

Note (1): The hardness after the post weld heat treatment shall be less than the specified value in

above Table.

Note (2): Hardness shall be taken on the area covered by each thermocouple.

(5) After Completion of work

Examination and Testing Acceptance Criterion (a) Visual check No extra distortion. (b) Hydrostatic and/or pneumatic leak test According to H-317E and no leak

shall be acceptable. (c) Wrapping for Underground Piping - Clean surface before wrapping

- Confirm materials, appearance

and thickness of wrapping according to H-103E

- No pinhole (Holiday Detector)


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DOC.No. H – 301 DHT PROJECT Sheet 36 of 39 6.1.2 If any of the welds examined reveals a defect requiring repair, the following

remedial action shall be taken : (1) When a repair or replacement is carried out, then the new work shall be

re-examined in accordance with this procedure. (2) If the repair is again found to be unacceptable, then repair shall be carried

out once more. Permissible number of welding repairs at the same place shall be a maximum of 3 (three) in carbon steel and 2 in alloy steel. If a further repair is required, then a cut out shall be the sentence. The welder concerned who made repair more than 3 times shall be retained only if requalified in accordance with Construction Procedure H-321.

6.2 Non-Destructive Examination 6.2.1 The weld joints of piping shall be examined to the extent specified in Table 6.2.1

with the following random examination procedure:

(1) The examination made at random shall consist of examining not less than one production weld joint selected from each production weld joint lot made by the same welder or welding operator defined as follows.

The above each production weld joint lot means;

(a) each 20 production weld joints or less for 5 % random examination,

(b) each 10 production weld joints or less for 10 % random examination and

(c) each 5 production weld joints or less for 20 % random examination, respectively.

(2) The examination shall be applied to the entire length of weld of the selected

joint, except as provided in (4) hereof. (3) The weld joints between dissimilar materials shall be examined by the

method used for the material requiring the more stringent examination. (4) Not less than one shot (with a 150 mm weld length) on one in each 50 girth

butt weld joints by each welder or welding operator for Category D Fluid Service as designated in the Specific Job Requirements attached hereto, shall be examined by the spot radiography.


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Table 6.2.1 Unit : %

Materi

al Flange Type of Type of Weld Examined

Fluid P-No. Class Examination Girth Butt Weld

Branch

Weld (1)

Socket Weld

Attachment Weld

150 300

Radiographic Examination Liquid Penetrant Examination

10 –

– 10

– 10

– –

1 600 Radiographic

Examination Liquid Penetrant Examination

20 10 (2), (3)

– 10

– 10

– 10

Normal Fluid

900 1500 2500


100 20

– 100

– 100

– 20

150 Radiographic Examination Liquid Penetrant Examination

10 –

– 10

– 10

– –

3, 4, 5,

8, 9B

300 600


20 10 (3)

– 10

– 10

– 10

900 1500 2500


100 20

– 100

– 100

– 20

Category “D”

Fluid (4)

All 150 Radiographic Examination Liquid Penetrant Examination

2 (5)

– – 5

– –

– –

Category “M”

Fluid (4)

All All Radiographic Examination Liquid Penetrant Examination

100 20

– 100

– 100

– 100


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Note: (1) : Welds of reinforcing plates are included. (2) : This shall be applicable to low temperature service and high tensile steel. (3) : This examination shall be performed for welded joints other than those to which radiographic examination was applied. (4) : The fluid service defined in ASME B31.3. (5) : As per Par. 6.2.1(4). (6) : The piping to be used under severe cyclic conditions defined in ASME B31.3 shall be examined by 100 % radiography.

6.2.2 When a random or spot examination of weld joints reveals a defect, the progressive examination for the same lot defined in Par. 6.2.1 shall be carried out as per the following procedure.

(1) Two additional weld joints of the same lot, by the same welder shall be

given the same type of examination; and (2) If the weld joints examined as required by (1) above are acceptable, all

items represented by this additional examination shall be accepted; but (3) If any of the items examined as required by (1) above reveals a defect,

two further weld joints of the same lot by the same welder shall be examined for each defective item found by that examination; and

(4) If all the items examined as required by (3) above are acceptable, all items

represented by this additional examination shall be accepted; but (5) If any of the items examined as required by (3) above reveals a defect, all

items represented by the random examinations shall be fully examined and repaired or replaced as necessary to meet the requirement of this specification.

(6) The defective item(s) revealed during progressive examination, shall be

repaired or replaced and reexamined at above each step as specified in Par. 6.1.2.


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6.2.3 The requirement for radiographic examination shall be as follows:

(1) Radiographic examination for the weld joints which PWHT is required, shall be carried out before and after PWHT unless otherwise specified.

(2) Prior to the radiographic examination, the scattering radioactivity around

the area shall be measured and the controlled area of the radioactivity shall established, providing sufficient countermeasures to prevent hazard of radioactivity.

(3) Radiographic examination by using Co 60 or Ir 192 will be instructed in

accordance with government regulations. (4) Number of films to be taken for one peripheral joint at radiographic

examination shall be equivalent to peripheral length of pipe (2 or more segments as required) with a film overlap of 25 mm or more

6.2. 4 Requirement for liquid penetrant examination shall be as follows:

(1) Liquid penetrant examination shall be carried out at root pass for girth butt weld and at cover pass for branch weld, socket weld and attachment weld.

(2) Procedure for random examination shall be in accordance with Par.

6.2.1 and 6.2.2 of this specification.

6.2.5 Magnetic particle and/ or ultrasonic examination may be carried out as supplementary, to ascertain the weld quality, or shall be substituted for Radiography as decided by PMC.

7. CLEANING AFTER PIPING ASSEMBLING AND ERECTION

Cleaning work after piping assembling and erection shall be performed in accordance with Construction Procedure H-315, Cleaning of Piping.

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