| Sr. No. | Check Points |
| P&ID RELATED |
| 1 | Following items are checked with the P&ID (IFD or later issue): |
| a) Line number and pipe class. |
| b) Tag nos. of equipment, instruments, special items, actuated and manual valves (if applicable). |
| c) Flow direction (including flow direction of check valve) |
| d) Slope/no pocket/free draining requirement, if any. |
| e) Min/max distances, straight lengths, etc. as specified in P&ID. |
| f) Close/open position for spectacle blind or spacer & blind. |
| g) Removable spool requirement, if any. |
| h) Sequence of branch connections (as agreed with Process in case of any changes). |
| i) Piping spec break, if any (preferably be at flange joints/valves, each iso to contain only one spec). |
| j) Special feature of valves (e.g. LO, LC, etc.) |
| k) Insulation symbol for insulated lines. |
| l) Equipment nozzle/TP numbers and tie-in numbers. |
| m) Insulating gaskets are selected as shown in P&IDs |
| n) Specific requirements mentioned in applicable P&ID notes (if any) are complied |
| LAYOUT RELATED |
| 2 | High point vents and low point drains are provided, as per project requirements, for lines that will be hydro-tested. |
| 3 | Drains are provided wherever liquid stagnation can occur in the lines e.g. downstream of a check valve. |
| 4 | Adequate pipe spool lengths are provided for wafer type butterfly and check valves to prevent the interference of the valve disc with adjacent piping items. |
| 5 | The platform/grade/building wall/dyke or bund wall/floor penetrations and limits of road crossings are properly shown wherever applicable. |
| 6 | The insulation limits are specified appropriately (esp. for personal protection) |
| 7 | The electrical tracing requirement and its limits are specified appropriately. |
|
| 8 | The wrapping and coating requirement and its limits are specified appropriately for u/g lines. |
| 9 | Minimum distance between welds is 50mm or five times the wall thickness whichever is greater, unless otherwise indicated in Project specifications. |
| 10 | Unions are provided in galvanized piping where threaded in-line items need to be removed for maintenance. Also, unions are provided at regular intervals (e.g. 24m) in straight pipe runs. |
| 11 | Full couplings are provided where applicable for small bore piping. |
| 12 | For piping below 2”, WN flanges are not directly welded to SW fittings. Also, PE pipes are not directly welded with swaged reducers (couplings are used in between). |
| 13 | Appropriate break-up flanges are provided in piping with internal lining and hot-dip galvanized piping (based on tub size). Spool configuration is made with one elbow or one tee only to ensure proper galvanizing. |
| 14 | Lifting lugs are provided for removable spools wherever required as per project requirements. |
| 15 | There is adequate clearance between pipe support and the adjacent piping component (e.g. flange, drain valve) to allow for flange bolt removal, valve operation, etc. |
| 16 | The valve stem orientation angle is indicated wherever the stem is not in the vertical and horizontal planes. |
| 17 | The piping interfaces with equipment/package nozzles/terminal points are checked (w.r.t. size, rating, flange face type and nozzle/TP nos.). |
| 18 | The straight length requirement for suction & discharge piping for compressors and certain pumps is as required by Vendor/project specs. |
| 19 | Straight lengths and branch configuration of upstream/downstream lines for anti-surge valves is as per Compressor Vendor’s recommendation. |
| 20 | The F/F dimensions of all valves, special items and in-line instrument items are as per approved vendor drawings. |
| 21 | The instrument connections are checked with Piping-Instrument interface drawings/Instrument hook-up drawings. |
| 22 | The rotameters are installed in vertical run with flow in upward direction. |
| 23 | The orifice tapping orientation is done considering liquid or gas flow as applicable and the BOM is as per the piping-instrument interface diagram. |
| 24 | The straight length requirement (u/s & d/s) has been provided for flow meters (e.g. flow orifices, flow nozzles, venture meters) and is as per Project standards/Vendor requirements. |
| 25 | The line configuration for lines containing magnetic flowmeters or vortex type flowmeters is such that they are always flooded. |
| 26 | Line configuration allows easy removal of spectacle blinds/spacers & blinds and valves in case of RTJ flange joints. |
| 27 | Flanged spools are provided in the case of conical strainers to enable removal. |
| 28 | Orientation of valve handwheel / lever is checked in model for proper access and commented accordingly |
| 29 | Line routing is visually checked in model for general requirement like access to in line items, supporting, clearances, obstructions, consistency and aesthetic requirement, etc. |
| 30 | Branches like drains, drip legs, etc. are located with sufficient clearance from the supports, steel or other obstructions so that they do not clash during expansion/contraction. |
| 31 | Drip leg size and dimension is checked with Standard drawing for steam lines. |
| 32 | Requirement of Weep holes for atm vent lines is indicated. |
| DRAFTING RELATED |
| 33 | The drawing border conforms to the Project specifications or Company standards, as applicable. |
| 34 | The isometric numbering is as per the approved project format and the line number matches with isometric number. |
| 35 | The correct isometric revision number is mentioned in the title block. |
| 36 | Pipe class printed at the bottom of the drawing matches with that in the line number. |
| 37 | Line data (e.g. process parameters, P&ID no., PWHT & testing requirements, insulation & painting specs, etc.) match with the Line List, if given in the isometric |
| 38 | Applicable reference documents (e.g. Line List, Isometric Index, Pipe Supports Spec, etc.) are mentioned. |
| 39 | Data such as inch-dia, etc. appear at the bottom of the isometric. |
| 40 | The “Cont. on …” description correctly appears at each end of the line isometric which is continued in another sheet. |
| 41 | The isometric print is readable (if required, the isometric should be split into more sheets). |
| 42 | Isometric number change is made preferably at a flange joint/valve (not at a weld joint). |
| 43 | Dimensions and elevations are adequately given. At least one elevation is mentioned and WP elevations for sloped lines are marked. |
| 44 | There are no HOLDs in the isometric (issue of any isometrics with HOLD requires approval by HOD/PEM). |
