Piping field fabrication & Installation works
Piping Field Fabrication works
Stainless steel, Alloy steel and carbon steel piping fabrication location works shall be sorted out with proper barrier. Classification of Alloy steel, Stainless steel and CS piping shall be sorted in different location and proper TAG and Board shall be placed to identify dissimilar materials. Care shall be taken while choosing the Stainless steel and Alloy steel Piping fabrication tools [Brush, grinding wheel, electrodes].
All piping materials upon arrival of MTC [Mill Test Certificate] shall be checked against the heat number of Pipe. Heat number of Pipe shall be marked [high lighted] by using marker. And proper color coding shall be done immediately upon unload. Heat numbers shall be punched on pipe. Each and every pipes and fittings shall be checked for physical damage, damage on edges and verify by using Vernier caliper the schedule of the pipe and ovality of the pipe. Rejected pipes shall be quarantined, NCR shall be prepared and send to vendor and client. Positive Material Identification has to be carried out for Piping materials as per requirement of Project specification.
Piping Isometric drawings shall be sorted as per continuation draw ings, Spooling and weld mapping shall be prepared. Required shop drawings shall be stamped and issued for fabrication, proper control of production shall be recorded every day.Completed fit-up spools, isometric drawings shall be highlighted. After fit-up inspec tion spools shall be sent for fabrication welding.
Most of important stage of piping fabrication is welding and qualified welder, WPS. Welder qualification shall be carried out by using qualified welding inspector, prior to offer for welder qualification welder has to be trained as per WPS to be used in produc tion, Mitigation of welding defects shall be explained to a welder. Proper qualification booth shall be prepared for mass welder qualification. Welders shall be qualified for dif ferent piping Materials grade, Thickness range, Diameter range, Welding process, Weld ing position. Dissimilar welding if required and multiple welding process. After welder Qualification, welder shall be issued a card and copy of the card shall be taken in record in QC department, and copy shall be maintained in Electrode issuance booth.
Weld management procedure shall be prepared and implemented at site. Required WPS- welding procedure Specification as per section IX shall be prepared and posted at welding area. [For eg: CS/CS welding works - CS WPS shall be posted near welding works so that welder can read and apply the required current and weaving]. The effective imple mentation of weld management will give the best result and reduce the rejection of welding.
Factors which affects the welding
Welder mindset, Welder training, Weather condition, frequent breaks during welding, Start and stop, pre-heating, interpass cleaning, use of portable oven, proper grounding, proper tools, fit-up, Welding booth. Baking and re-baking.
Testing [Destructive and Non-Destructive Testing]
With reference to the requirement of standard and specification percentage of Destruc tive and Non-Destructive Testing shall be decided. RT/UT/MPI and Hardness Testing, all fabrication completed spools after visual check send for NOT Testing.Weld Joints marked and identified for Testing. NDT accepted spools transferred to Sandblasting and painting. After the painting inspection spools delivered to site. Proper Tag to be fixed.
Piping Installation works
Prior to Installation of piping, pipe rack handover documents shall be received from Structural contractor. Priority shall be given to full length pipes shall be laid on rack as per General Arrangement drawings.
All full-length pipe shall be lifted and pipe support shall be installed and proper Level and alignment shall be maintained. Fabricated spools shall be connected and Field joints shall be welded and subjected to inspection and Testing.
After completion of piping as per Isometric drawing, complete line shall be verified against ISOMETRIC/GA/Pipe supports. Completed lines shall be subjected to Hydro test ing/Pneumatic Testing. All lnline instruments shall be removed prior to Testing. After completion of successful testing, all instruments and valves reinstated and bolt torque ing shall be performed.
Final Paint touch up works shall be carried out. And color bands shall be printed and permanent labeling shall be printed on Pipe with Direction of flow.