piping and instrument diagrams

7/29/2019 Piping and Instrument Diagrams

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Piping & Instrument Diagrams

Barry M Barkel PE


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Communication for Engineers

VerbalAssignments, Instructions, updates

WrittenReports, Procedures, Specifications

Mathematical

Calculations, data, Performance statistics

SymbolicDesigns, Process Documentation


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Drawings are Engineerings

INTERNATIONAL LANGUAGE

engineers all over the world can understand them


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TYPES of DRAWINGS

Process Flow Diagrams: What a Process Does

Piping & Instrument Diagrams: How it works

Layout Drawings: How it looks

Mechanical Drawings: |

| How to build it

Construction Drawings: |


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dwg1


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Uses of P&IDs

Develop Operational methodology

Develop Safety Philosophy and Design

Develop Control Philosophy

Basis for Control Programming

Communication Document for Project


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Uses of P&IDs

Serves as Design Basis for:

Equipment Design

Piping DesignEstimating

Purchasing

Used to evaluate construction progress

Training basis for Operational Personnel


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Characteristics of P&IDs

Grouped by specific sections of the process

Schematic; NOT a scaled layout

Clear; uncluttered

Systematic; uniform

Usually confidential

Revised often with Revisons clearly identified


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Elements of a P&ID

Equipment & valves identified

Instrumentation type & location identified

Path between instruments & control devices indicated

Piping size and type identified for all lines


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Identification of Equipment

Identification by type

w/ specific code designation..ie TK

w/ a specific standardized shape

Identification by number

w/ specific item numberie TK 101

Identification by namew/ what the unit is called.. ie methanol tank


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Valve Identification

Identification by type


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Instruments

Instruments may be: Indicators

or Part of a control system

Instruments often have several components:

sensing elements

transmitterscontrol elements


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Some Instrument Designations

P = pressure I = indicator

T= Temperature C = controller

F = Flow S = switchL = Level E = element

T = transmitter

G = gage

ISA designations usually used


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Instrument Configuration

PI106

TT110

1

TE101


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Control Paths

Hardwired

Computer program


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Piping Designations

Line Codes

Spec breaks


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Line Codes

Size

Service

Matl of Constr or Piping Spec

Insulation amount and Spec


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Pipe size

Nominal diameter

1, 2 1/2, 4 etc.


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Pipe Service

Coded to a designation shown on P&IDs

Examples: Methanol- Me

Reactor Product Stream- RxP


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Material of Construction

Generic

Examples- PVC

316L S/S

Company or Project SpecificationExamples- PP1

( a specification covering the materials andjoining methods for PVC plastic pipe)


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Insulation Code

Thickness of insulation ( inches)

Type or Insulation Specification

Example- F ( fiberglass)

- IN 9 ( Project Specification for

Calcium Silicate System)

Tracing CodeExamples- S (steam)

E (electric)


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Total Line Code

Example-

2 dia., Type 304 s/s pipe in acetic acid

reactor discharge service, insulated with1 of fiberglass insulation

2AARX-304S/S-1F


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Spec Breaks

A Line /Code changes every time ANY

ELEMENTin the code changes

IE 3AARX-304L S/S-1F --> 3AARX-304L S/S

at the point where the fluid has cooled enough to

eliminate the insulation.

3AARX-304L S/S-1F 3AARX-304L S/S

Spec Breaks are shown as --------------]-------------


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Notes on P&IDs

Normally read LEFT to RIGHT

TOP to BOTTOM

The Stream No.s, Ts, Ps and Flows

from the PFD do NOT appear on a

P& ID

Equipment numbers are the same as on

the corresponding PFD


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THANK YOU

Qs ?

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