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RECOMMENDED COLD CUTTING PROCEDURE FOR TIE‐INS /DISMANTLING OF HYDRO CARBON PIPING/PIPELINES (A)
SURVEY 1‐ How to ensure the line, which require cold cutting. • For Above Ground piping/pipeline check either P&ID or General Lay out drawing for confirmation • For underground use slit trench method to ensure the correct line. If necessary multiple slit trenching shall be done to establish that the correct line is selected. 2‐ Perform thickness check in case of live piping/ pipeline. 3‐ Remove external coating from the location where cold cutting to be carried out under ground piping /pipeline
(B)
Arrange the following 4‐ 5‐ 6‐ 7‐ 8‐ 9‐ 10‐ 11‐ 12‐
(C)
Cold cut M/C with spare cutting blade 2 nos minimum gas plugs of suitable size 3/4” ‐2 HP Hose for connection with Gas Plug 1” ‐2 nos Hose connected with water tanker Sealing Material Belt Vacuum Tanker (In case of Liquid) Water Tanker Compressors, Cranes as required to execute the works HSEMS IMPLENTATION
13‐ 14‐ 15‐ 16‐ 17‐ 18‐ (D)
Permit to Work system implementation PPE’s as required Confined Space if working inside trench H2S /Gas Monitoring Availability of Fire extinguishers/ water tanker with Hose Nitrogen Tanker for Purging Execution
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Ensure that area where the work to be performed is safe and ready Work permit to be taken for Preparatory as well as for Cold Cutting Work Excavate the area 1.5 meters to both side and 0.75 m to 1m deep from the Bottom of Pipe for free movement during execution of work in case of under ground piping/pipeline Thickness of piping/pipeline to be checked in case of tie‐ins to new system Ensure the existing piping / pipeline is completely depressurized. In case of crude, recommended to flush the existing piping/pipeline with fresh water to the maximum possible extend and the liquid drain shall be collected in the existing close drain system or shall be collected in safe area and pumped out using vacuum tanker. In case of Gas, the line shall be completely depressurized and recommended to purge the line with nitrogen up to safe limit
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before performing the work. It is also recommended to keep the purging until the cold cutting is in process, is completed. For underground piping / pipeline , clean the location of the pipe where cutting is to be performed ‐ 8” (suitable for the width of the cutting machine) to either side of cutting point ,suitable for holding the cold cutting machine Install cold cutting m/c on the existing pipe. Keep a collecting drum under the cut with Vacuum Tanker hose in case of liquid. Upon completing the first cut, mark the second location considering all measurements such as (Flange length+ RF+ Gasket) and to provide 5mm to accommodate the prefab spool. (Refer Fig‐1).Do not mark and start cold cutting at both location simultaneously in case of tie‐in work. Once 2nd cut is nearing completion, hold the cut piece firmly by crane with wide propylene belt to avoid any movement of cut piece. Before removing cut pieces, start pouring water on both sides of the cut to avoid any spark generation due to metal to metal contact. Once the cut piece is removed stop pouring water. Tie‐in to existing Piping/Pipeline Before start of any hot work, permit to be taken along Confined Space Permit in case of under ground piping/pipeline. Insert Gas Plug on both end of existing piping/pipeline and seal the edge of the plug with proper sealing material properly. Connect ¾” hose one end to the Gas Plug and other end of hose to be put away in a container which is full with water.(To avoid hazardous condition) (Refer Fig‐2)
Before start of any grinding or welding work check presence of gas inside the wall of piping/pipeline as well as surrounding area inside the trench by gas detector instrument (Gas Checking shall be a continuous process while hot work is going on) (E) PRECAUTION: 1. Ensure that the cold cutting is completely done. If not use a manual hacksaw blade to cut fully. 2. Do not try to remove the cut piece if the cut is incomplete and not detached from the parent pipe. 3. Do not hammer the cut piece to remove from the parent pipe since this sort of breakage may create sparks. 4. Ensure the area is free to meet any unforeseen condition.
NOTE: During whole process, KOC HSEMS procedures shall be strictly followed
Prepared by: Mohammad Shoeb