Checking Piping Drawings Procedure

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DISCLAIMER

This Procedure is intent to prepare for the Piping Checkers perfection.

Piping Info

accepts no

liability or responsibility whatsoever for it in respect of any use of or reliance upon this procedure

by anyone or any entity.

1.0 PURPOSE

The purpose of this design procedure is to ensure accuracy and completeness of piping drawings

issued by the Mechanical Design Department; and identify responsibility, criteria, and specific items

to be checked by the Mechanical Design Checker.

2.0 MECHANICAL DESIGN CHECKER RESPONSIBILITY

2.1 Responsible that the piping drawings are complete, accurate, interference free,

constructible, maintainable, in compliance with System Design and Checking Guides,

standards, standard deliverable drawings, project design criteria, vendor data, Process

and Instrument Diagram (P&ID), project contract, and engineering requirements.

2.2 Responsible to verify the location and limits of drawing HOLDs to areas that are

incomplete or can not be verified and approved by the checker prior to issue due to

insufficient engineering, vendor, client or other discipline information.

2.3 Responsible to verify that all reference data and documents used to perform the check

are the most current available. This includes vendor drawings, P&ID’s, design criteria,

thermal analysis, other discipline drawings and models. Use the Designed Piping

System Folder that contains design information gathered by the Designer and Lead

Designer for each system.

2.4 Use a hard copy “check print” of the drawings for marking comments in red for

correction that include additions, changes, or deletions. Graphics, dimensions, and

notes that are verified to be correct shall be highlighted in yellow. Comments, notes,

references, etc that are not for correction shall be made in black graphite pencil.

2.5 Upon completion of the initial drawing check, the Checker shall return the check prints

to the originator or Lead Mechanical Designer for correction along with the Designed

Piping System Folder. After correction, the Checker is responsible to “back check” the

drawing to assure all corrections and engineering comments were incorporated

accurately.

2.6 Responsible to check the complete content of the drawing and piping system design

including but not limited to all items contained in this procedure. The checker shall

contact the Mechanical Lead Designer or Engineer for additional project specific

requirements.

2.7 Responsible to maintain check prints, records, and information until the piping system is

fabricated, installed, and operating.

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3.0 DRAWING INFORMATION CHECK

3.1 Drawing Number. Check that the drawing number is in accordance with the project

numbering system, client numbering system.

3.2 Drawing Revision Number/Letter and Description. Check that the drawing revision

number/letter is correct in the title block and revision description block according to

project revision numbering system. Check that the revision description in the revision

block describes the purpose for the drawing issue or changes.

3.3 Drawing Title Block Information. Check that the text in the drawing title block is correct

in accordance with the project standards Deliverable Drawings.

- Project Description

- Drawing Type Description (Piping Isometric, Underground Piping Isometric, Small

Bore Piping Isometric, Analyzed Small Bore Piping, etc)

- Piping System Description

- Scale

3.4 Drawing Signatures. Check that drawing signatures are correct in the title block.

3.5 Back Circles. For revised drawings only, check that back circles are place around

revised areas to identify changes since the previous drawing issue. Check that back

circles from previous revisions have been removed.

3.6 Drawing Notes. Check that general and specific notes are in accordance with the

example on WorleyParsons’ Standard Deliverable Drawings and are applicable to the

drawing content and project specific requirements.

- Check drawing number references listed within the general notes.

- Check Technical Specification number listed within the general notes.

- Check Insulation Specification number listed within the general notes.

3.7 Drawing Attributes. Check that the line graphic and text attributes meet the

requirements of the Project Cadd Specification.

3.8 Spelling and Abbreviations. Check the spelling of all text and abbreviations within the

drawing. Periods after abbreviations are not required.

3.9 North Arrow. Check that a north arrow is on the drawing, including at detail plan views.

3.10 Project Specific Requirements. Check with the Lead Designer and Project Design

Criteria for any project specific drawing or pipe system requirements.

4.0 PIPING SYSTEM INFORMATION CHECK

4.1 System to P&ID Check. Check that the pipe system matches the approved system P&ID

including comments found on the project’s Master Set of P&ID’s. The checker is

responsible that the piping drawing and the P&ID are in agreement for the following:

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Pipe Line Number

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Pipe Sizes

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Pipe Line Specifications and locations of Line Spec changes within the pipeline.

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Pipe Insulation Class

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Branch and Component sequence

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Equipment Tag Numbers and Descriptions

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Component Tag Numbers

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Flow direction

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Heat Tracing limits, type, and thickness

4.2 Equipment Location, Description, Tag Number. Check the coordinate (n/s, e/w, and

elevation) locations of all equipment to which the pipe system is connected in the model.

The location shall match the general arrangement, equipment setting plan, and

civil/structural drawings. Check that the equipment description and tag number match the

P&ID and Mechanical Equipment List.

4.3 Equipment Nozzle Location, Tag Number and Data. Check the equipment model nozzle

location, size, connection end preparation, flange rating, pipe schedule are in accordance

with the latest equipment vendor drawing.

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Check that nozzle information on piping drawing is correct

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Butt Weld nozzles shall include the nozzle pipe schedule or wall thickness

4.4 Piping Connection to Equipment Nozzle. Check the pipe connecting to the equipment

nozzle matches the nozzle attributes and is compatible.

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Flat Faced or Raised Faced Flanges

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Butt Weld Nozzles requires matching material and pipe wall thickness. Identify

dissimilar metal welds and wall thickness between nozzles and pipe.

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Non-USA vendor may provide nozzles that do not comply with ASME B16.25 weld

bevel standards. Identify locations of any pipe joint that requires a bevel different than

the ASME standard.

4.5 Flow Direction Arrow. Check that each pipe line contains one flow direction arrow. Each

sheet of a piping isometric shall contain a minimum of one flow direction arrow.

4.6 Completeness. Check that all dimensions, notes, information, and details that are

required for the construction and installation of the piping are included.

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Compliance with System Design Guides. Check that the piping system is designed in

accordance with the Mechanical Design Department specific system design guides.

4.7 Project System Design Criteria Documents. Check that the piping system is designed in

compliance with project/client design criteria documents.

4.8 Valve and In-Line Components. Check all valves and in-line pipe components (flow

elements, expansions joints, orifice plates, restricting orifices, etc) end to end dimensions

and connection attributes from approved vendor drawings. Check that the connection

size, type and schedule match the attributes of the pipe. Check all valve actuators for

correct size, orientation and that they are accessible for operation and maintenance.

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Standard end to end dimensions per ASME/ANSI B16.10 for valves 600 lb class and

below may be approved without approved vendor drawings for gates, globe, and

check valves. All other valves shall be on hold until approved vendor drawings are

available.

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Butterfly, control, ball, plug, and relief valve end to end dimensions do not conform to

end to end standards and shall be on hold until approved vendor drawings are

available.

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Identify dissimilar metal welds and wall thickness between component and pipe.

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Check that chain wheel operators are provided on non accessible valves.

4.9 Valve, Flow Element, and In-Line Component Installation Requirements.

Check vendor drawings and installation instructions for installation requirements of

valves, flow elements and in-line components within the pipeline.

- Straight pipe upstream and downstream requirements

- Valve stem orientation (especially butterfly valves)

- Clearances for valve maintenance and disassembly.

- Lugged butterfly valves shall be noted on drawings for proper bolting procurement.

- No gaskets required at low pressure butterfly valves and expansions joints.

- Flat face flanges required at flanged expansion joints

- Flat face flanges are required at cast iron equipment flanges

- Flow element upstream and downstream straight pipe requirements according to the

Control System Engineer requirements.

4.10 Vents and Drains. Check quantity and location of vents and drains. Check that all vent

and drain connections reference the correct standard detail number.

4.12 Minimum pipe spool lengths. Check that there are adequate pipe spool lengths

between pipe line components. Use the following as a guide. Large Bore Butt Weld:

Minimum spool length equivalent to the length of a butt weld reducer. Small Bore

Socket Weld: Minimum exposed pipe length between socket weld components ends

shall be 2”.

4.13 Separation Distances for Branches. Check that there is adequate separation distance

between pipe branches and adequate separation distances between branches and

pipe line ends or components.

4.14 Instrument Connection Orientation and Access. Check that instrument connections

that require access are accessible and that the orientation on the pipe is correct.

Check for proper connection type and size. Check that all Instrument connections

reference the correct standard detail number, and there are sufficient clearances for

element removal from pipe.

- Temperature connections shall be located downstream of pressure connections.

- Temperature thermowells cannot be installed in pipes smaller than 3”.

4.15 Insulation and Insulation Support Lugs. Check insulation requirements to Project

insulation class codes and thickness. Add insulation support lugs on vertical runs of

alloy pipe.

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4.16 Heat Tracing. Check that piping is Heat Traced as identified on the system P&ID and

in accordance with the Project Heat Tracing Criteria.

4.17 Pipe Penetrations symbols. Check that all concrete floor, platform grating, wall, and

grade penetrations are indicated and labeled on piping isometrics. Callout core drilled

openings in existing walls when required.

4.18 Waterstops. Check that water stops are provided on underground piping at floor and

wall penetrations.

4.19 Slope. Check that pipe systems that require slope have the proper minimum slope

and the correct slope direction. For hot piping verify pipe does not reverse slope in hot

position.

4.20 Pipe Supports and Welded Attachments. Check that pipe supports are shown when

required and locations, quantity, and tag numbers have been review and approved by

the Piping Engineering department. Check that shop welded pipe support attachment

details are provided on alloy piping for shop welding before shop stress relieving.

4.21 Material List on Isometrics. Check that all pipe and pipe component material

descriptions in the isometric drawing material list matches the engineering pipe line

specification.

4.22 Insulating Flange Kits. Check that insulating flange kits are identified on aboveground

piping systems connecting to underground pipe systems where required by the

pipeline specification.

4.23 Dissimilar Metal Welds. Check that dissimilar metal welds that may occur at valves,

equipment nozzles, and material spec changes are identified and transition pieces are

provided if required.

4.24 Dissimilar pipe and/or component wall thickness. Check that dissimilar pipe and

component wall thicknesses that may occur at valves, equipment nozzles, and at

material spec changes are identified and transition pieces or taper bores are provided

if required. ASME Power Piping Code B31.1 Section 127.3C allows a 1/16” (.0625”)

internal pipe wall misalignment (each side) for welding without taper boring the

connecting pipe. Example of piping drawing identification of dissimilar wall thickness

taper bore: TAPER BORE SCH 160 PIPE TO MATCH SCH 80 VALVE

5.0 PIPING SYSTEM ROUTING AND LAYOUT CHECK

5.1 Interference Check. Check that the system is interference free by a visual review of the

model and that a recent electronic interference report from the model had been reviewed

and cleared. If a non 3D project, review all discipline reference drawings. If the pipe

routing is within an existing plant area, verify a field interference check was performed.

For hot piping verify pipe clearances in hot positions.

5.2 Thermal Analysis. For hot piping verify WorleyParsons Piping Engineering Department

has approved the thermal flexibility of the pipe. Checker is responsible to obtain pipe

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thermal movements and verify clearances in hot position and that pipe does not reverse

slope causing low point pockets. Thermal movement’s direction and distance shall be

noted on check prints in blue for future reference.

5.3 Hazardous Areas. Check that no electronic instrument, valve actuator, or other electronic

component within the pipe or attached to the pipe falls within a Hazardous Area of the

plant.

5.4 Plant Personnel Access, Construction Access, Maintenance Areas, and Safety. Check

that the pipe system layout does not obstruct plant personnel access, construction

access, and maintenance areas of the plant. Check that the pipe system lowest

appendage (including pipe support clamps) is above 6’-8” headroom and does not affect

plant safety.

5.5 Pump and Equipment Requirements. Check that the pipe system layout meets the

requirements of the connecting equipment vendor requirements or common practice.

The checker shall read all vendor criteria. Examples:

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Pump suction straight diameters, eccentric reducers

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Steam Turbine vendor requirements

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Check pipe system against Equipment Vendor P&ID if applicable

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Installation and Maintenance Manuals

5.6 System Discharge Points. Check that safety valve discharges, gas vents, etc are

discharged in a safe location that will not be harmful to personnel, structures, or

equipment. Confirm safety valve discharges do no impact noise abatement requirements.

Confirm gas (fuel gas, hydrogen) discharge points are indicated on hazardous area

location drawings.

5.7 Underground Pipe Burial Depth. Check that underground pipe has adequate cover to

protect from crushing from vehicle, railroad, and crane loads and is below frost depth.

5.8 Pipe Lanes. Check that pipe system layout is within established pipe north/south,

east/west pipe lanes and elevations established within the plant. Underground piping shall

have common bottom of pipe elevations for trenching.

5.9 Structural Gusset Plates. Check that the pipe system does not interfere with areas to be

occupied by structural gusset plates. Not all gusset plates are in the model and those

that are modeled may not represent the actual structural fabricators detail and

requirements. Checkers must do a visual model interference check at gusset plate areas

and interface with structural design to assure sufficient clearances.

5.10 Circulating Water Branch Component Reinforcement Plate clearance. Check for

potential interferences in the area of large pipe component reinforcement plates,

especially at crotch areas of laterals.

5.11 Underground Potable Water and Waste Water Separation. Check local and state

codes for separation requirements between underground potable water and waste

water systems to prevent pollution of potable water.

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5.12 HDPE Pipe Fitting Separation and Butterfly Valves. Check that there are pipe spools

between all HDPE pipe fittings to accommodate differences in physical dimensions

between HDPE fitting manufactures. Check that Butterfly Valves discs are not

obstructed from opening when connected to heavy wall HDPE pipe. Pipe spacers

may be required between the flange and valve body.

5.13 Clearance from vertical structural columns and walls. Check that pipe routing

maintains approximately 9 inches of clearance from vertical structural columns and walls

(including hot position) to allow space for field routed utilities.

5.14 ‘Olet Branch Dimensions. ‘ Olet type pipe branch fittings (weldolet, sweepolet, etc)

dimensions (run pipe centerline to the fitting outlet) are approximate because the

dimension varies by manufacture. Check that fitting to fitting design on the outlet of

the ‘olet branch fittings is not used. A pipe spool is required for adjustment by the pipe

fabricator to suit actual fitting dimensions while maintaining the overall geometry of

the pipe system.

5.15 Miscellaneous Items for Checking List. Includes commonly found piping isometric

Isogen software errors requiring manual annotation.

a) Orifice Flange pressure tap orientations incorrectly shown by Isogen.

b) Dimensions or dimension strings starting at pipe caps. Isogen dimension is

from cap work point (center of cap where blue line stops) but dimensions

on drawing appears to be from end of cap.

c) Eccentric Reducer offset dimensions incorrectly shown by Isogen do not

match actual fitting offsets as manufactured and should be deleted.

6.0 HOLDS CHECK

6.1 Holds. Check the location and limits of drawing HOLDs to areas of the drawing that are

incomplete or can not be verified and approved by the checker prior to issue due to

insufficient engineering, vendor, client or other discipline information. See Section 2.2.

6.2 Hold List. Check that all drawing holds are included in the Holds List for the project.

7.0 PIPING DRAWING CHECK LIST

7.1 Check List. A summary of the items identified in this procedure is provided in

ATTACHMENT 1 “Piping Drawing Check List”.

This list may be printed and used as a checking tool or record at the discretion of the

Mechanical Design Checker.

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ATTACHMENT 1

PIPING DRAWING CHECK LIST

DRAWING INFORMATION CHECK

3.1 Drawing Number

3.2 Drawing Revision Number/Letter and Description

3.3 Drawing Title Block Information

3.4 Drawing Signatures

3.5 Back Circles

3.6 Drawing Notes

3.7 Drawing Attributes

3.8 Spelling and Abbreviations

3.9 North Arrow

3.10 Project Specific Requirements

PIPING SYSTEM INFORMATION CHECK

4.1 System to P&ID Check

4.2 Equipment Location, Description, Tag Number

4.3 Equipment Nozzle Location, Tag Number, and Data

4.4 Piping Connection to Equipment Nozzle

4.5 Flow Direction Arrow

4.6 Completeness (All required dimensions, notes, information, details required for