Gap Control for Socket Weld Back Welded Threaded Fittings

Project Title : WASIT DOWNSTREAM PIPELINES PROJECT

Client : SAUDI ARAMCO

Contractor : GULF CONSOLIDATED CONTRACTORS CO. LTD.

Contract No. : 6600025971

B. I. No. : 10-00918

Document Code : GCC/PQP/505

PROJECT QUALITY PLANProcedure No. Appendix Rev. No. Date

QCP-505B-M-06 17 (Annex B) 0 JULY 03, 2012

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QUALITY CONTROL PROCEDUREQUALITY CONTROL PROCEDUREFORFOR

GAP CONTROL FOR SOCKET WELD & GAP CONTROL FOR SOCKET WELD & BACK-WELDED THREADED FITTINGSBACK-WELDED THREADED FITTINGS

QCP-505B-M-06QCP-505B-M-06

QUALITY CONTROL PROCEDUREQUALITY CONTROL PROCEDUREFORFOR

GAP CONTROL FOR SOCKET WELD & GAP CONTROL FOR SOCKET WELD & BACK-WELDED THREADED FITTINGSBACK-WELDED THREADED FITTINGS

QCP-505B-M-06QCP-505B-M-06





B. I. No. : 10-00918




CONTENTS

1.0 SCOPE & PURPOSE

2.0 REFERENCES

3.0 RESPONSIBILITIES

4.0 PROCEDURE STEP (Socket Joint Gap Control)

4.1 Shop or Bench Procedure

4.2 Field Socket Welds (field Access)

4.3 REPAIRS

5.0 APPENDICES

6.0 ILLUSTRATION

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B. I. No. : 10-00918




1.0 SCOPE & PURPOSE

This QC Procedure describes the method to be followed in controlling the gap in the socket weld fittings and to confirm the required numbers of engaged threads of threaded connections that are to be seal-welded, are complying with project requirement.

The purpose is to implement, establish and maintain the necessary axial gap between the male and female component of socket-weld fittings, and to verify the thread engagement of back-weld threaded fittings, are met prior to welding.

2.0 REFERENCES

This procedure shall be in accordance with the requirements of the following Saudi Aramco Standards and other applicable industry codes:

SAES-L-110 Limitations on Pipe Joints and Components SAES-L-350 Construction of Plant Piping SAES-W-011 Welding Requirements for On-Plot Piping G.I. 2.100 Work Permit Systems ASME B1.20.1 Pipe Threads, General Purpose (Inch) ASME B16.11 Forged Fittings, Socket-Welding and Threaded

3.0 RESPONSIBILITIES

Piping/Mechanical Supervisor

Responsible for preparing the equipment, hand tools and personnel for the installation and/or welding of socket welds and back-welded threaded fittings in accordance with project schedule and quality requirements. He shall also be responsible in securing work permit prior to start working.

Welders and Fabricators

Responsible for performing quality welding and/or installation of socket welds and back-welded threaded fittings for new pipelines or pipe spools in accordance with project schedule and quality requirements.

QC Welding Inspector

The QC Welding Inspector is responsible for ensuring installation and/or welding of socket weld and/or back-welded threaded fittings is in accordance to this work procedure and other Saudi Aramco reference standards and/or drawings. The Welding Inspector is also responsible for in-process and final inspection and acceptance of completed joints. QC Welding Inspectors procedure shall verify 100% of fit-ups are in strict accordance with this procedure.

4.0 Procedure Step (Socket Joint Gap Control )

Material Control has issued fittings that have been adequately degreased using an approved method that does not affect weldability. Fittings are identifiable and traceable to project specifications & are acceptable for installation.Construction Supervisor (and/or Welding Engineer) checks specs & approves this special process work action. Fitters check piping ends and fittings to assure no oily residues exist. Pipe ends shall be squared, cut using dry method, reamer, cleaned & ready for fit-up. Approved welders (tackers) with valid JCC cards are available to tack. Approved drawings are followed/redlined & pipefitting quality practice achieves pipe lengths and fittings for assembly.

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B. I. No. : 10-00918




4.1 Shop or Bench Procedure: Utilize these steps where lines are easily accessible. Note: Good Fit-up Practice & workmanship in accordance with SAES-L-350 Piping Tolerances and shall be verified by QC

a) Verify socket depth is per ASME B16.11 (See Attachment 2) or applicable spec & free of oily residue.

b) Using a Scribe* (Mechanical mark), mark a point exactly 25 mm from pipe end. QC "WITNESS" dimension. QC shall use a permanent marker (Sharpy pen recommended) & circle the 25 mm verification mark "as accepted".

c) Insert the pipe fully into the socket fitting until the pipe/nipple is "driven home" (*contacts the inner socket face)

d) Using a scribe or file (Precise Mech. mark) or approved "permanent" marker unharmful to mat'l (low chloride), mark the pipe in the area projecting from the socket. (Mark is flush with the edge of the fitting). Note: Lead pencils are not recommended as they leave lead traces in weld zone. *Knife-edge files that lightly nick the metal are ok.

e) Retract piping 3 mm (approx. 1/16" per code) above the edge of the fitting using the mark as reference.

Note: The two mechanical marks shall be aligned & visible prior to tack welding by an approved Welder (valid JCC). Neither mechanical mark is covered by subsequent tack welding until visual verification of gap by QC.

f) Tack the weld in place using equal-spaced tacks 12mm long minimum using an approved WPS. See Note Below!

Note: Tack welding shall be considered in root pass weld sequence. All tacks are performed with same care, materials, electrodes, minimum preheat, and procedures that are used for permanent socket weld root passes.Tack welds are incorporated into the final weld and shall be thoroughly cleaned, prepared at each end, & inspected for cracks. Any cracked tacks shall be removed before welding the joint. Technique note: On a 1" socket joint, 3 tack welds at 12.5 mm long will make up one half of entire root pass. Feather ends before filling root pass gaps

g) QC inspects joint fit-up for the following (checks are performed and done first by the responsible trained fitter) QC measures gap from the upper mechanical mark to edge of the fitting & visually verifies a 3 mm gap from the reference mark to the edge of the fitting. Using the known socket depth, the QC (use chart) verifies the fit-up. QC also checks tack weld quality (root penetration) & notes evidence of oil fouled tack welds. Also, the quality of the fit-up is visually checked (to verify that the joint is not misaligned "as tacked"). QC accepts fit-up. OK to weld!.

h) Unacceptable fit-up is corrected and accepted by QC after achievement of desired & verified gap before welding. Repeated unacceptable fit-up is addressed by Construction Engineer or Master Pipefitter on a case-by-case basis.

i) Welder completes welding utilizing the approved welding sequence in Attachment 3 (Figure 1, 2, 3, etc) and makes two passes in such a way to assure adequate fusion (no cracks), root penetration, minimal porosity & slag. QC verifies this by visually inspecting clean, feathered tacks for weld quality and surveillance of root pass weld out.

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Note 1: Welders making socket welds and encountering oil residues (porosity, slag, etc in weld passes) shall have weld joints adequately cleaned (using approved methods) before completing the welding process.

Note 2: Welders making socket welds are qualified on their first 3 production welds per socket weld quality criteria of 01-SAIP-01. Welders producing unacceptable welds shall be retrained or removed from socket welding activities.

4.2 Field Socket Welds (Field Access): Use this procedure & Notes where field access is difficult. Good Fit-up practices are important. If RT is to be applied as part of a socket gap verification program, field welds are the best place to perform RT. It is widely known and accepted fact that fit-up errors account for the main cause of socket weld failures due to a lack of "engagement".

Fit-Up Tolerance: A socket weld is acceptable to SA when engagement = 50% of socket depth.ENCOURAGE HONESTY & ACCOUNTABILITY WHEN MISTAKES ARE MADE. USE THE ABOVE TOLERANCE!Causes:

1) Pipe fitters rush work and often fail to follow good practice to assure acceptable gap.

2) Small diameter piping runs are often improperly supported during installation. This accounts for sagging lines, fit-up errors & rework.

3) Difficulty in achieving access will result in incorrect or "best effort" measurements from climbing pipefitters. Master Pipefitters have a variety of skills related to measurement taking and tools to assure sound measurements.

It is often the inexperienced pipefitter/helper combination that fails to take correct measurements & then resorts to the improper socket gap (lack of engagement) in lieu of rework. This is verified in the many RT results. The 25 mm mark (Field Welds) becomes a QC "WITNESS POINT" to assure Gap control.

a) Verify socket depth is per ASME B16.11 (See Attachment 5) or applicable spec & free of oily residue.

b) Using Scribe or file (Mechanical mark) mark a point exactly 25 mm from pipe end. QC Witness* POINT!

This is the only difference for Field Work ( Hold Point )

4.3 Repairs: Repairs are inevitable and can occur due to such things as incorrect measurement & error, piping modifications, revisions, damage, RT results unacceptable, etc . Corrective action requires a list a do's & don’ts for Socket Weld Quality (Procedure)

Dos (Inspection Hold Points)

1. Involve Inspection in all repair efforts. Visual Inspection & NDT shall be per the Inspector's call in all cases.

2. Ensure great care in removal of welds by grinding or carbon arc gouging. Reason: Pipe ThicknessTechnique: Grind parallel to top of fitting/perpendicular to pipe (as access allows) taking great care not to reduce the pipe wall thickness nor reduce the socket depth. A smaller grinder using a 75 mm grinding wheel works best. Use of carbon arc gouging shall utilize the smallest "copper clad"

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3. Follow procedure for weld removal and reuse of fittings. A maximum of one weld repair attempt shall be permitted for socket welds in all cases before replacement of material. RT is an option for Project Inspection here.

Reason 2 repairs are not advisable: Small diameter fittings lose their "form" and become distorted at joint root. In case of oil fouling and hydro test failure/repairs due to 100% through weld porosity, perform full NDT (RT) on retest

Best Practice: Often, replacement of small diameter sections with couplings & short piping lengths will save great time & cost (NDT). Evaluate repairs using common sense.

4. Check socket depth after weld removal to assure "J" dimension has not been altered. See Att. 2 Buttering fittings is not allowed. Replace the fitting in the event that socket depth or "form" is altered.

5. Check piping for "minimum" wall thickness violations due to weld removal. UT as necessary. Technique: Use a straightedge (fillet gauge), VWAC, or pit gauge to identify suspected/visible wall loss.

6. Check excavation due to gross weld defects (Crack, fusion, LORP, etc) to determine complete removal.

7. Always follow up excavations for defects & repairs with a Surface Method NDT & close visual exam.

8. Always assure piping meets the correct fabrication tolerances after repairs.

9. Always document socket weld repairs on a QC report form & detail any extensive repairs.

Don'ts1. Cut out a weld without notifying Inspection & having a clearly defined procedure to cover repairs.

2. Perform a repair if the access does not lend itself to Quality. Follow Best Practice & use common sense.

3. Perform repairs by placement of strain on the piping using "cold spring" to correct gap deficiencies.

4. Do repairs without QC documentation.

5.0 Appendix:

Saudi Aramco Inspection Checklist (SAIC):

SAIC-W-2037- Inspect Welding of Socket Joints and Seal Welding of Threaded Joints

6.0 ILLUSTRATION

SOCKET WELDING@ SA (WELDING SEQUENCE )

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# 1 - Acceptable Socket Weld (Three passes, two visible) w/ Good Joint Root Penetration/Fusion (GTAW or SMAW) weld width = 3 x filler metal diameter (P-No1) - CSD Recommended Sequence.

# 2 - Acceptable Socket Weld (Two Passes, Both Visible) w/ Good Joint Root Penetration/Fusion GTAW or SMAW) weld width = up to 5 x filler metal diameter – Acceptable.

# 3 - Acceptable Socket Weld (Two Passes, Only one Visible) w/ Good Joint Root Penetration/Fusion Note: (GTAW Process) weld width = up to 5 x filler diam. - Acceptable (Inspect Root Pass or RT)

Unacceptable Socket Weld Profile

Socket weld size & Acceptable weld profile (For reference only)

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RT Acceptance criteria per SA Insp Procedure 01-SAIP-01 Table 8 (Socket Weld & Welder Qualification)

Note: The welders who fail RT and cannot produce quality socket weld free of defects (01-SAIP-01 & B31.3 criteria), are restricted from socket welding. Additionally, random RT (for gap and weld quality

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B. I. No. : 10-00918




verification) shall be performed whenever just cause exists (per Para. 17.1.3), esp. if welders are found welding on oily matl. RT extent is a matter for procedures. Zero is required with a Verification Method per Attachment 1 - (Sample Gap Control Quality Procedure). Minimize your RT through Quality.

The "J" Dimension (Typical Socket Depth) of ASME B16.11

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Socket welded valves on process lines as per SASD AB-036521 – 001

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Socket Flanges: This does not fall under socket fittings & ASME B16.11. See ASME B16.5 (Table 8)

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Documents

Gap Control for Socket Weld Back Welded Threaded Fittings