P&ID CHECKLIST:

General:

Ensure P&IDs are not crowded: Normally do not show more than 4 pieces of

equipment per P&ID

Verify the P&ID matches Process Flow Diagram (PFD) connectivity

Verify spec breaks over valves/PSVs, steam and electrical tracing are shown

Verify all equipment numbers and specs agree with process data sheets or

specifications and equipment list

Verify insulation requirement for piping, equipment and instruments are shown where

required

Verify piping, valve, equipment and instrument symbology and numbering.  Verify

symbology against standard legend, symbols and instrument interface

Include notes for any items rotated for easy access, such as handwheels on valves, to

ensure they are rotated to an angle that is possible considering the number of bolt

holes on the lines. (Ex: per ASME B16.5 I see that for 150# carbon steel, 0.5″ to 3″

lines can rotated 90 degrees , 4″ to 8″ lines can rotate 45 degrees , 10″ to 14″ can

rotate 30 degrees)

Verify revision, purpose of revisions, numbering, and P&ID title

Show notes whenever any items must be within sight of each other (e.g. ensure level

gauge can be seen by someone operating this manual globe valve)

Verify notes for reference drawings (including Decommissioning/Removal P&IDs)

Verify all Notes/Holds are relevant. Is it clear what they refer to? Spellings correct?

Are the general project notes and holds, which must be added to each drawing, in

place?

Verify utility P&IDs tie in correctly to main drawings, and show connection to utility

stations & analysers

Verify all the mark-ups were applied by the drafters correctly, spellings all correct

Check the drafting process did not introduce any random new errors or mistakes away

from areas revised/marked-up

Verify revision triangles, clouds, and other markings in the revision process are added

or deleted as required

Verify provisions for future expansion are shown, if anticipated

Check for company’s document/drawing number

Check for client document number

Check for licensor/Vendor document number

Verify that title block By/Approved/Checked are blocks filled and signed. Date,

Revision, all company logos, and client signoff blocks are shown. Verify P&IDs are

properly signed

Conduct a pre-HAZOP of processes in each P&ID or related P&IDs

Conduct a pre-Constructability review

Clear all HOLDs before final issue.

Process lines:

Verify line number, cross check with line schedule and sizing. Verify pipe specs are all

shown and correct

Verify line arrows are on each turn of a line, in the correct direction

Verify lines connecting to a main flare line connect to that line from above, even

making a detour if necessary to ensure proper drainage

Show tie Points are at all old/new line interfaces and ensure the tie-in schedule

revision agrees with the P&ID revision

Verify branching or reducing lines connect to each other according to project’s piping

branch table

Verify header line numbers include all header block valves (so that when the header is

built the block valves are installed with the header, not any branch lines)

Ensure when process lines cross, vertical lines break for horizontal lines. But

instrumentation lines break for process lines except specified otherwise

Verify reference to other P&IDs and line continuity through off-page connectors.

Alignment of OPCs is important

Stream tags include the fluid and drawing number. Note where the equipment name

the stream is from/going to

Verify, where applicable, streams come in the left side and go out the right side of

P&IDs

Show slopes and elevations where required

Verify all battery limits are clearly marked

Instrumentation lines:

Verify instrumentation signal lines are correct line type, local/DCS code correct

Verify complete instrumentation and control loops are shown on the P&IDs

Instrumentation:

Instruments are right type, local/transmitted, control type, block/bypass valves shown

Verify if instrumentation details is as per job specification (isolation valve size and

spec., vent & drain requirements, etc.)

Verify that Cause-and-Effect/Safe Chart requirements are clearly represented

Valves:

Verify Control valve type, failure mode shown, block/bypass valves, reducers, the sizes

used are the latest from controls department

Verify Pressure Relief Valves are correct. Verify set pressure, PSV size is latest

calculated, inlet/discharge size and pipe spec match latest calculations, outlet lines are

Car Sealed Open or have no valves (if to atmosphere), the relief outlet goes to

drain/flare/atmosphere

Verify block valves show if they are normally open or closed, car sealed open or

closed?

Verify drain valves present, use smaller gate valve symbol, they are between

checks/gates/etc

Verify minor valves are placed logically (check valve near pump discharge, swing blind

near a gate valve)

Verify spectacle blinds are correctly shown normally open/closed and they are on the

side of the valve facing the “danger” (i.e. pressure source, contamination source)

Verify double-block valves are shown (with 3/4″ drain between) where procedures say

they are needed i.e.600 psig+ or for hazardous fluids like acids

Verify consistency of double block and bleed

Verify proper valving for drain and relief valves

Verify all sizes are indicated and match the process calculations: control valves, relief

valves, by pass…

Verify low temperature impact if expansion (control valve, relief valve,

depressurization)

Verify operability for start-up, opening of valve with high differential pressure

especially riser valves

Verify that working range of control valve is adequate or needs split-range

Verify if failure position of shutdown and control valves are shown

Verify any by-pass requirements and appropriate valving is shown

Verify if full bore and reduced bore ball valves are indicated where appropriate

Equipment and vessels:

Verify all equipment tags and titles above equipment show spelling of names correctly

Verify stream tags include the fluid and drawing number. Note the equipment name

and where the stream is from/going to

Verify equipment names match other documents like the PFD, equipment list,

datasheet, etc.

Verify isolation of equipment (spectacle blind, double block and bleed) with job

standard

Verify equipment, data and level diagrams are filled in and match the process

calculations

Verify all equipment numbers and specs agree with process data sheets or

specifications and equipment list

Verify all the nozzles of an equipment including drain, vent, manholes etc. have been

shown

Vessels should show – Size, design temperature/design pressure, full vacuum,

internals/levels, skirt height to grade

Verify all the set points are indicated

Heat exchangers should show – Area, design temp/pressure, duty, motor horsepower

(air coolers), condenser/reboilers have elevation, motors have controls

Heater should show – size, duty, design T/P, coil arrangement, utilities on a separate

page

Boiler should show – size, design T/P, superheater outlet T, utilities own page

Tank should show – size, capacity, type, heaters/agitators shown

Pump should show – rated flow, horsepower, and differential head. Showing temporary

strainers, drains, motor w/ controls

Turbines should show – in/out temp/pressure, horsepower, strainers

Compressors should show – Actual Cubic Feet per Minute inlet, discharge pressure,

driver type, horsepower, strainer, lube/seal oil

Verify steam outs/steam connections are where required and show full vacuum rating

on equipment when required

Verify limit of package, limit of supply / vendor scope

Verify all SP items are indicated

Verify that all installation requirements are shown: i.e. no slope, high point, min.

straight length, no pocket, min. length, etc.