Also, PE pipes are not directly welded with swaged reducers (couplings are used in between).Īppropriate break-up flanges are provided in piping with internal lining and hot-dip galvanized piping (based on tub size). 24m) in straight pipe runs.įull couplings are provided where applicable for small bore piping.įor piping below 2”, WN flanges are not directly welded to SW fittings. Also, unions are provided at regular intervals (e.g.

Unions are provided in galvanized piping where threaded in-line items need to be removed for maintenance. Minimum distance between welds is 50mm or five times the wall thickness whichever is greater, unless otherwise indicated in Project specifications. The wrapping and coating requirement and its limits are specified appropriately for u/g lines. The electrical tracing requirement and its limits are specified appropriately. The insulation limits are specified appropriately (esp. The platform/grade/building wall/dyke or bund wall/floor penetrations and limits of road crossings are properly shown wherever applicable. downstream of a check valve.Īdequate pipe spool lengths are provided for wafer type butterfly and check valves to prevent the interference of the valve disc with adjacent piping items. High point vents and low point drains are provided, as per project requirements, for lines that will be hydro-tested.ĭrains are provided wherever liquid stagnation can occur in the lines e.g. N) Specific requirements mentioned in applicable P&ID notes (if any) are complied M) Insulating gaskets are selected as shown in P&IDs L) Equipment nozzle/TP numbers and tie-in numbers. K) Insulation symbol for insulated lines.

I) Piping spec break, if any (preferably be at flange joints/valves, each iso to contain only one spec).

H) Sequence of branch connections (as agreed with Process in case of any changes). as specified in P&ID.į) Close/open position for spectacle blind or spacer & blind. of equipment, instruments, special items, actuated and manual valves (if applicable).Ĭ) Flow direction (including flow direction of check valve)ĭ) Slope/no pocket/free draining requirement, if any.Į) Min/max distances, straight lengths, etc. No.įollowing items are checked with the P&ID (IFD or later issue):ī) Tag nos. Here is a checklist for Piping Isometrics Sr.

Piping isometric drawing standards pdf