Pipelaying Tender-VOL II - WorleyParsons.com

EPMC SERVICES FOR REWARI – KANPUR PIPELINESPECIFICATION FOR WELDING ON ONSHORE PIPELINEAll tack welds shall be welded vertical-up.Preheat of tack welds shall be the same as the approved welding procedure specification for thatpipe or fitting grade, size and thickness.Tack welds incorporated into the final weld shall be ground to a featheredge at each end to ensureadequate fusion on the root pass.9.5 Line-up ClampsInternal line-up clamps shall be used to hold the pipes firmly in position. Unless otherwise agreedin writing by the OWNER, internal line-up clams shall not be removed before the completion of thefirst pass.For all tie-ins (closing welds) and all welds where external line-up clamps are used, vertical-upwelding shall be used for the root pass.External line-up clamps may be removed when the root pass is at least 50 percent complete andequally spaced around the pipe circumference, subject to the pipe remaining adequatelysupported.The pipes on both sides of the weld joint shall not be raised, lowered, or otherwise moved, untilboth the root pass and the second pass (hot pass) have been completed, unless theCONTRACTOR can demonstrate to the satisfaction of OWNER that the root pass alone isadequate to resist deformation and cracking.9.6 Working ClearanceThe working clearance shall be such as to afford the welder maximum comfort during welding. Aminimum 400mm clearance shall be maintained.n:\513-mh-2145-rkpl\11 engineering\11.8 pipelines\06 spec\specification for welding on onshorepipeline\mh2145-c000-pl-spc-0020.docMH2145-C000-PL-SPC-0020 RevA Page 20 of 42