Process Industry Practices Process Control PIP PCEDO001 ...

April 1997

Process Industry Practices

Process Control

PIP PCEDO001

Guideline For Control Systems Documentation

PURPOSE AND USE OF PROCESS INDUSTRY PRACTICES

In an effort to minimize the cost of process industry facilities, this Practice has

been prepared from the technical requirements in the existing standards of major

industrial users, contractors, or standards organizations. By harmonizing these technical

requirements into a single set of Practices, administrative, application, and engineering

costs to both the purchaser and the manufacturer should be reduced. While this Practice

is expected to incorporate the majority of requirements of most users, individual

applications may involve requirements that will be appended to and take precedence over

this Practice. Determinations concerning fitness for purpose and particular matters or

application of the Practice to particular project or engineering situations should not be

made solely on information contained in these materials. The use of trade names from

time to time should not be viewed as an expression of preference but rather recognized

as normal usage in the trade. Other brands having the same specifications are equally

correct and may be substituted for those named. All practices or guidelines are intended

to be consistent with applicable laws and regulations including OSHA requirements. To

the extent these practices or guidelines should conflict with OSHA or other applicable

laws or regulations, such laws or regulations must be followed. Consult an appropriate

professional before applying or acting on any material contained in or suggested by the

Practice.

©Process Industry Practices (PIP), Construction Industry Institute, The

University of Texas at Austin, 3208 Red River Street, Suite 300, Austin,

Texas 78705. PIP member companies may copy this practice for their internal

use.

Not printed with state funds

April 1997

Process Industry Practices Page 1 of 10

Process Industry Practices

Process Control

PIP PCEDO001

Guideline For Control Systems Documentation

Table of Contents

1. Introduction ..................................2

1.1 Purpose..............................................2

1.2 Scope.................................................2

2. References....................................2

2.1 Process Industry Practices (PIP).........2

2.2 Industry Codes, And Standards ..........2

3. Definitions.....................................2

4. Requirements ...............................3

General ....................................................3

Process Control Diagrams (PCDs) ............3

Piping and Instrument Diagrams (P&IDs)..3

Standards and Practices ...........................4

System Block (Architect) Diagrams...........4

Master Instrument Index ...........................4

Narrative Specifications............................5

Instrument Data Sheets(Specification Forms) ............................5

Level Instrument Documents.................... 5

Control Valve Calculations ....................... 5

Flow Instrument Calculations.................... 5

Computing Device Calculationsand Calibration...................................... 6

Logic Documents...................................... 6

PLC Programming Guidelines .................. 6

Distributed Control System (DCS)Guidelines............................................. 7

Alarm Setpoint Listing .............................. 7

Layout Drawings....................................... 7

Instrument Location Drawings .................. 8

Instrument Installation Drawings............... 8

Instrument Loop Diagrams ....................... 8

Complex Loop Descriptions...................... 9

Instrument Wiring Documents .................. 9

Grounding System Drawings .................. 10

Instrument Installation Checkout andCalibration/Configuration Procedure.... 10

Decommissioning Documents ................ 10

PIP PCEDO001Guideline For Control Systems Documentation April 1997

Page 2 of 10 Process Industry Practices

1. Introduction

1.1 Purpose

The purpose of this Practice is to provide control systems design personnel with

recommended basic criteria for creation of control systems documentation for use in

the process industry.

1.2 Scope

This Practice defines the general guidelines for control systems documentation for

design, supply, installation, checkout or commissioning, and maintenance of

instrumentation and control systems. The practice is primarily used for the process

type industries such as chemical, and petroleum refining.

2. References

When adopted in this engineering guide or in the Contract Documents, the latest edition of the

following codes, standards, specifications, and references in effect on the date of contract

award shall be used, except as otherwise specified. Short titles will be used herein when

appropriate.

2.1 Process Industry Practices (PIP)

– PIP PCCGN001 - Process Control General Design Specification

2.2 Industry Codes, And Standards

• The International Society for Measurement and Control (ISA)

− ISA S5.1 - Instrumentation Symbols and Identification

– ISA S5.2 - Binary Logic Diagrams for Process Operations

– ISA S5.4 - Instrument Loop Diagrams

– ISA S20 - Specification Forms for Process Measurement and Control

Instruments, Primary Elements and Control Valves

– ISA S91.01 - Identification of Emergency Shutdown Systems and Controls

that are Critical to Maintaining Safety in Process Industries

3. Definitions

For the purposes of this engineering guide, the following definitions apply:

Owner: The entity with final responsibility for the complete operation of the facility.

Contractor: The owner’s hired representative, providing any combination of engineering,

procurement and construction services.

PIP PCEDO001April 1997 Guideline for Control Systems Documentation


4. Requirements

General

Prior to the project initiation, the Owner should provide the engineering contractor an example

of the Owner's standard documentation package.

Comment: It is recommended that the owner should complete, with input from the

Contractor as required, PIP PCCGN001.

Prior to project initiation, the Owner should convey to the Contractor, in writing, all necessary

changes and/or modifications related to this guideline.

The Owner may use the engineering contractor’s standard documentation as an alternate.

On retrofit projects the Owner may require that changes be made to existing drawings or

documents in lieu of generating new drawings or documents.

Basic criteria for each type document are described one by one below. The Owner should

specify which documents are to be used for the project.

Comment: The use of a system of data bases and/or drawing tools, which are tied to the

Piping and Instrument Diagrams (P&IDs) electronically, is encouraged to generate

instrument index, instrument data sheets, instrument loop diagrams, installation details, and

other applicable documents.

Owner/Contractor should jointly identify the critical instruments and controls to be

implemented in this project as described in ISA S91.01.

Process Control Diagrams (PCDs)

A PCD is a schematic representation of basic control philosophy, showing the main control

scheme for the process.

A PCD is normally developed prior to development of the Piping and Instrument Diagrams and

is a useful tool for the control strategy discussion.

Piping and Instrument Diagrams (P&IDs)

A P&ID is a schematic representation of the piping, process control and instrumentation for a

specific process/system, showing the functional relationship among the various components.

A P&ID, as a key document conveying the great amount of system design information,

provides a means for communicating with the project design groups, owners, regulatory

agencies, and others to establish thorough understanding of systems.

In general, ISA S5.1, Instrumentation Symbols and Identification, should be used as the guiding

document for instrument symbology.



Standards and Practices

The accepted standards and/or practices that establish the basic design criteria for the project

should be listed and developed at the beginning of the project. Unless otherwise stated in

writing, PIP practices should be used.

Standard Symbologies for Computer Aided Drafting (CAD) drawings should be defined by

Owner and/or Contractor.

System Block (Architect) Diagrams

System Block (Architect) Diagrams will show in a block diagram format all major control

systems components and the overall cable/wiring connection philosophy.

Master Instrument Index

The index database contains information on all the instruments in the project and is effective

for determining current work completion status and for ascertaining that required work has

been performed and documents have been issued.

The master instrument index should be the key reference document for the control systems

work and is generated as a product of the data base. The document should contain a record for

every instrument tag number used in the project. Instrument index should have the following

fields:

a. Instrument Tag Number

Comment: The instrument tag number may be divided into multiple fields such as

Unit (or Plant, Train) Number, Function Identifier, Equipment (or P&ID) Number,

and Loop Sequence Number.

b. Service Description

c. Reference Drawing Number such as P&ID (or Mechanical Flowsheet) Number

d. Instrument Type

e. Signal Type

f. Instrument Location (field, local panel, control room, etc.)

g. Line Number (mainly for in-line devices)

h. Pipe Specification (may be combined with Line Number)

i. Data Sheet Number

j. Critical Status

k. Material Requisition or Purchase Order Number

l. Design Drawings such as:

– Location Plan

– Loop Diagram

– Installation Details



– Logic Diagram

– Electrical Wire Diagram or Schedule

– Vendor Print

Other useful fields can be added per project specific requirements.

Narrative Specifications

A written technical specification should be prepared for a complicated system such as

distributed control system, programmable logic controller, complex analyzer system, burner

management system, etc.

Narrative specifications supplement the instrument data sheets when data sheets do not

adequately define the general requirements for a category of instruments.

Instrument Data Sheets (Specification Forms)

Instrument data sheets are prepared to present the basic information for the instrument

requisition. When completed, they provide a readily accessible, concise summary of

information about installed instrumentation.

ISA S20 or equal should be used.

The instrument data sheet should define the instrument in sufficient detail as to allow a vendor

to select the appropriate instrument.

Level Instrument Documents

Level Instrument Documents are provided to depict level instrument connection requirements,

standpipe requirements, and level operating ranges and setpoints.

Beginning in preliminary form, the Level Instrument Documents will communicate the level

instrument connection requirements to Vessel and Piping groups and assist a control systems

engineer in selecting the types and ranges of level instruments including providing data for the

range calculations.

Control Valve Calculations

Preliminary control valve calculation methods should be defined at the beginning of the project.

The final control valve calculation should be representative of the selected valve and

documented accordingly, using the vendor sizing method.

The final control valve data should include, as a minimum, instrument tag, sizing data, (such

as flow rates, pressure drops, etc.) calculated and selected Cv, and sound level prediction.

Flow Instrument Calculations

All flow sizing methods should be defined at the beginning of the project as the owner's,

vendor's, or engineering contractor's methods.

Each flow instrument calculation sheet should have, as a minimum, the instrument tag, sizing

data, and calculation results.



Computing Device Calculations and Calibration

Requirements described herewith apply to all computing devices. For DCS and other digital

systems, a configuration block is normally self documented in the system.

Comment: The instrument vendor's standard calculation/calibration form should satisfy this

documentation requirement.

The engineering contractor should provide the basis for all calculations, including:

a. Final calculations including determination of constants.

b. Limitations of the computing device constants.

Logic Documents

A number of different documents may be used to define the logic functions:

Logic Narratives

Logic narratives in plain language can be used to define the logic functions.

Logic Diagrams

a. ISA S5.2 may be used as a guide to develop logic diagrams. ISA S5.2 is intended

to symbolize the binary operating functions of a system in a manner that can be

applied to any class of hardware.

b. Logic diagrams are typically used to transfer operational information from the

Owner to the party responsible for generating the application program.

Ladder Diagrams

a. Logic programmed in ladder diagram form is common for the programmable logic

controller (PLC). The party implementing PLC based logic systems should be

required to supply ladder diagrams that satisfy the requirements of the logic

diagrams and/or logic narratives.

b. Ladder diagrams preferably are generated by the program development

workstation software tools, and should be transmitted to Owner in hard (printout)

and soft (diskette) format.

c. Register listing and necessary annotation for PLC should be provided for

explanation of the program.

Cause and Effect Diagrams

Cause and effect diagrams show the initiating events and required results for the logic

functions.

Batch Sequence Diagrams

Batch sequence diagrams identify the required batch sequence operations.

PLC Programming Guidelines

Prior to the PLC programming, rules governing the PLC programming should be established.



As needed, notes should be added to the rung of the logic or ladder to explain each function.

The Input/Output (I/O) and the register listing should be provided. A backup for electronic

files in addition to the master is required.

Distributed Control System (DCS) Guidelines

Prior to the DCS configuration, a DCS hardware and software design guide should be

established. Typical issues to be defined in this guide are:

a. Nametag convention

b. Alarm presentation philosophy

c. Input/Output segregation philosophy

d. Redundancy/System Security philosophy

e. Configuration guidelines

f. Graphics development guidelines

g. Interface guidelines (interface with the third party devices such as computer, PLC,

analyzer system, tank gauging system, etc.)

h. Spare capacity guidelines

In most cases, the selected DCS will provide self documentation of the configuration that is

installed. The DCS documentation should include the I/O listings for the various types of

signals. If the DCS configuration software does not provide for self documentation, some other

means such as documenting the configuration data on a database should be provided.

A backup electronic file for the configuration data base is required.

Alarm Setpoint Listing

Alarm setpoint listing (both soft and hardwired alarms) should be available to cover shutdown

alarm and pre-shutdown or critical set points.

Alarm settings should include the process value and the signal value.

The form of the documentation for this information should be determined at the beginning of

the project. Using the loop folder or master instrument index for this purpose is an example of

many available options.

Layout Drawings

Control Room

Control room layout drawings should show in plan view the location of consoles, panels,

control racks, computer racks and peripherals, logic racks, barrier cubicles, termination

racks and boxes.



Control Panel

Control panel layout drawings should show the position of panel mounted instruments,

panel dimensions, method of support, filler plates and major construction details for

control panels.

Control Console

Control console layout drawings should show the console bay arrangements with function

identification for each process area video system.

Remote Building

Remote building (DCS Satellite Building, Analyzer House, etc.) layout drawings should

show the position of each item of major equipment.

System Cabinet

System cabinet layout drawings should show the location of all pieces of equipment,

cabinet dimensions, terminal boxes, filler plates, and major construction details.

Instrument Location Drawings

Instrument location drawings should show the appropriate location coordinate of each field

instrument.

The Instrument Location Drawing is a plot plan with buildings, vessels, and other major

equipment shown in outline.

The Instrument Location Drawings may also show routings for tubing bundles, cables, air

supplies, or electrical supplies as appropriate.

Instrument Installation Drawings

Instrument installation drawings should show the required method of installation of the

instruments and shall list the needed piping, tubing and fitting materials, etc. Refer to PIP

instrument installation details.

Instrument Loop Diagrams

In general, ISA S5.4 should be used to develop instrument loop diagrams.

Instrument loop diagrams may include the following information:

a. All devices or items with clear labeling and identification, at least including instrument

tag numbers

b. All junction boxes, terminal strips, bulkheads, ports, grounding connections, etc. and

all identifying numbers for all equipment, electrical cables, conductor pairs, and

pneumatic tubes

c. All utility and energy sources: electrical power, air supply, hydraulic fluid supply.

Designate source of power, voltage, pressure, and other applicable requirements.

d. All references to supplemental records and drawings such as P&ID Number, etc.

Process Industry Practices Process Control PIP PCEDO001 ...

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