CHECKLIST FOR PIPING ISOMETRIC

CHECKLIST FOR PIPING ISOMETRIC

Piping Isometric drawing is an isometric representation of single line. It is the most important deliverable of piping engineering department.Piping fabrication work is based on isometric drawings. It shows the straight lengths of all the pipe runs on the drawing as clearly as possible. Indicating the line numbers for pipe runs clearly within the drawing. The line number indicates the fluid service, piping class and material, insulation details etc.

Data Required for Checking Piping Isometric

Sr no	Documents	Purpose
1	P&ID (Piping and Instrumentation Diagram)	To identify Line Size, Line Number, instrumentation, valves , insulation and other Special requirements.
2	Plot Plan	To shows the equipment and supporting facilities (pipe racks, structures, buildings, roads) that are required for the process facility within a battery limit area.
3	Building GA	To identify Equipment Location & Orientation.
4	Equipment GA	To check the Nozzle Location & Orientation , Nozzle size etc
5	PMS (Piping Material Specification)	To check Piping material
6	Line List	To check design Pressure & temperature, Insulation Requirement, Stress critical Line, hydro test detail, etc.
7	Valve data sheet	To check valve size , type of actuator, etc.

P&ID RELATED

1.   Line number and pipe class.
2.      Flow direction (including flow direction of check valve)
3.      Min/max distances, straight lengths, etc. as specified in P&ID.
4.      Removable spool requirement, if any.
5.      Slope/no pocket/free draining requirement, if any
6.      Equipment nozzle/TP numbers and tie-in numbers
7.      Close/open position for spectacle blind or spacer & blind.
8.      Tag nos. of equipment, instruments, special items, actuated and manual valves (if applicable).

LAYOUT RELATED

· High point vents and low point drains are provided, as per project requirements, for lines that will be hydro-tested

· Drains are provided wherever liquid stagnation can occur in the lines e.g. downstream of a check valve.

· 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.

· The platform/grade/building wall/dyke or bund wall/floor penetrations and limits of road crossings are properly shown wherever applicable.

· The insulation limits are specified appropriately (esp. for personal protection)

· Minimum distance between welds is taken as per Project specifications.

· Unions are provided in galvanized piping where threaded in-line items need to be removed for maintenance. Also, unions are provided at regular intervals in straight pipe runs.

· Full couplings are provided where applicable for small bore piping.

· 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).

· 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.

· Lifting lugs are provided for removable spools wherever required as per project requirements.

· The piping interfaces with equipment/package nozzles/terminal points are checked (w.r.t. size, rating, flange face type and nozzle/TP nos.).

· The electrical tracing requirement and its limits are specified appropriately.

· The straight length requirement for suction & discharge piping for compressors & pumps is as required by Vendor/project specs.

· The wrapping and coating requirement and its limits are specified appropriately for u/g lines.

· Straight lengths and branch configuration of upstream/downstream lines for anti-surge valves is as per Compressor Vendor’s recommendation.

· The F/F dimensions of all valves, special items and in-line instrument items are as per approved vendor drawings.

· The instrument connections are checked with Piping-Instrument interface drawings/Instrument hook-up drawings.

· 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.

· Line configuration allows easy removal of spectacle blinds/spacers & blinds and valves in case of RTJ flange joints.

· Flanged spools are provided in the case of conical strainers to enable removal.

· Orientation of valve handwheel / lever is checked in model for proper access and commented accordingly

· Line routing is visually checked in model for general requirement like access to in line items, supporting, clearances, obstructions, consistency and aesthetic requirement, etc.

· 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.

· Drip leg size and dimension is checked with Standard drawing for steam line.

CODE AND STANDARD

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Title Block

Line Number
Isometric Drawing Number
Sheet Number
P & ID Number
Piping Layout/GAD Drawing Number
Project Name, Project Code and Area Code
Insulation and Heat Tracing Type (If the line is insulated only)
Line Testing Type.
Inspection Class
Hydro-test / Pneumatic test pressure
Design Pressure and Design Temperature (It’s not mandatory)

Drawing Area

Iso North
Equipment name and location
Co-ordinates for all equipment
Nozzle orientation
Nozzle size and tag
Angle allocation and direction (clockwise or anti-clockwise)
Nozzle centreline elevation
Line elevations (it can be center line or BOP (Bottom of Pipe) elevation)
Line offset angle and direction
Slope (if it’s required as per project)
Line number with complete spec detail
Spec break (If required)
Dimensions of all components and spools
Fluid flow direction
Support locations
Continuation isometric drawing number (if the complete line do not fit in the single sheet)
Instrument location and tagging.
Valve orientation
Control Valve location and arrangement.
Orifice Meter straight run requirement
Field weld and Workshop weld Identification