IEC 62382:2024

Control systems in the process industry - Electrical and instrumentation loop check

IEC 62382:2024 defines procedures and specifications for loop check, which comprises the activities between the completion of the loop construction (including installation and point-to-point checks) and the beginning of cold commissioning. This document is applicable for the construction of new plants and for expansion or retrofits (i.e. revamping) of electrical and instrument (E&I) installations in existing plants (including PLC, DCS, panel-mounted and field instrumentation). It does not include a detailed checkout of power distribution systems, except as they relate to the loops being checked (i.e. a motor starter or a power supply to a four-wire transmitter). Loop checks can be performed throughout the lifecycle of the plant. This document is also applicable when loop checks are performed after commissioning. This document describes what is intended to be tested but not how the test is performed, due to the wide range of technologies and equipment available.
The intent of this document is to provide a means for all parties, including the owner, the installer and the vendor, to clearly establish and agree on the scope of activities and responsibilities involved in performing these tests in order to achieve a timely delivery and acceptance of the automation system. The activities described in this document can be taken as a guideline and adapted to the specific requirements of the process, plant or equipment.
This edition includes the following significant technical changes with respect to the previous edition:
a) general re-organization of the content of the previous edition, moving informative content to the annexes;
b) replacing the forms based on I/O type in IEC 62382:2012, Annex A to Annex E with an example of a generic loop check form;
c) providing additional references to other applicable standards.

Systèmes de commande dans l’industrie de transformation - Contrôle de boucle des circuits électriques et des appareillages

IEC 62382:2024 définit les procédures et les spécifications relatives à un contrôle de boucle, qui se compose des activités comprises entre l’achèvement de la construction de la boucle (installation et contrôles de point à point) et le début de la mise en service à froid. Il s'applique à la construction de nouvelles usines, ainsi qu'à l'extension ou à la modernisation des installations de systèmes électriques et instruments de fonctionnement (E&I - electrical & instrument) dans les usines existantes (PLC - programmable logic controller, DCS - distributed control system, appareils montés sur panneau et appareils de terrain compris). Elle ne comprend pas de vérification détaillée des réseaux de distribution d'électricité, hormis dans la mesure où ils sont rattachés aux boucles faisant l'objet du contrôle (c'est-à-dire dans le cas d'un démarreur de moteur ou d'une alimentation électrique pour un transmetteur à quatre fils). Les contrôles de boucle peuvent être effectués tout au long du cycle de vie de l’usine. Le présent document s'applique également aux contrôles de boucle effectués après la mise en service. Le présent document décrit ce qui est destiné à être soumis à l’essai et non la méthode d’essai en raison de la large plage de technologies et d’équipements disponibles.
Le présent document a pour objet de permettre à toutes les parties, y compris le maître d’ouvrage, l’acheteur et l’installateur, de définir clairement et de convenir de l’étendue des activités et des responsabilités liées à l'exécution de ces essais, afin de finaliser la livraison et l'acceptation des systèmes d’automatisation dans les délais prévus. Les activités décrites dans le présent document peuvent être considérées comme des lignes directrices et être adaptées aux exigences spécifiques du processus, de l'usine ou de l'équipement.
Cette troisième édition annule et remplace la deuxième édition parue en 2012. Cette édition constitue une révision technique.
Les principales modifications par rapport à l'édition précédente sont les suivantes:
a) réorganisation générale du contenu de l’édition précédente, en déplaçant le contenu informatif vers les annexes;
b) remplacement, dans les Annexes A à E de l’IEC 62382, des formulaires fondés sur le type d’E/S par un exemple de formulaire générique de contrôle de boucle;
c) ajout de références supplémentaires à d’autres normes applicables.

General Information

• Status: Published
• Publication Date: 13-Aug-2024
• ICS: 25.040.40 - Industrial process measurement and control
• Technical Committee: SC 65E - Devices and integration in enterprise systems
• Drafting Committee: WG 3 - TC 65/SC 65E/WG 3
• Current Stage: PPUB - Publication issued
• Start Date: 14-Aug-2024
• Completion Date: 06-Sep-2024

Relations

• Revises: IEC 62382:2012 - Control systems in the process industry - Electrical and instrumentation loop check
• Effective Date: 05-Sep-2023

Overview

IEC 62382:2024 is an international standard published by the International Electrotechnical Commission (IEC) that governs the procedures and specifications for conducting electrical and instrumentation loop checks in the process industry. This standard applies to the phase between the completion of loop construction-including installation and point-to-point checks-and the start of cold commissioning. It covers new plant constructions as well as expansions and retrofits of electrical and instrumentation (E&I) installations, including PLCs, distributed control systems (DCS), panel-mounted devices, and field instrumentation.

The main objective of IEC 62382:2024 is to establish clear and agreed-upon activities and responsibilities among all parties involved-such as plant owners, vendors, and installers-to ensure the timely delivery and acceptance of automation systems through thorough loop checks. The standard does not prescribe how tests should be performed, recognizing the diversity of technologies and equipment across plants. It can also be applied post-commissioning for maintenance or troubleshooting purposes.

Key Topics

• Loop Check Scope
  Focuses on activities after loop construction and before cold commissioning; excludes detailed power distribution system checkout except where directly related to loops.

• Loop Check Activities
  Covers documentation review, visual inspection, and functional checks to verify the integrity and correct operation of electrical and instrumentation loops.

• Phases of Loop Check
  Defined phases ensure structured verification-from preliminary documentation checks to final functional tests.

• Deficiency Management
  Identification, documentation, and resolution of deficiencies found during loop checks are emphasized for quality assurance.

• Exclusions
  The standard excludes prior and post activities outside loop checks, regulated industry-specific requirements, safety instrumented systems, manufacturing execution systems, advanced process control, and security-specific procedures.

• Documentation and Reporting
  Details the required documentation format for loop check results, including a generic loop check form example replacing previous forms based on I/O types.

• Quality Assurance and Safety
  Stresses the importance of quality control and safety considerations throughout loop check activities.

Applications

IEC 62382:2024 is used extensively within the process automation and control industries, particularly where control systems require precise electrical and instrumentation testing before commissioning or after maintenance. Typical applications include:

• New Plant Construction
  Verifying control loops in newly installed systems to ensure operational readiness before startup.

• Plant Expansion and Retrofit Projects
  Applying standardized loop check processes during modifications or additions to existing E&I systems.

• Maintenance and Troubleshooting
  Performing loop checks post-commissioning to address system faults or verify repairs.

• Automation Vendor and Installer Coordination
  Facilitating clear communication of responsibilities and scope between all stakeholders involved in control system delivery.

• Compliance and Quality Control
  Helping industries maintain compliance with internal quality requirements and external standards by formalizing loop check procedures.

Related Standards

IEC 62382:2024 references several other international standards and documents relevant to industrial automation and process control, including but not limited to:

• Standards governing power distribution systems in relation to control loops.
• Guidelines on safety instrumented systems and security protocols for industrial control systems.
• Documentation and testing standards for automation device integration and quality assurance.
• Related IEC and ISO standards that coordinate terminology, procedures, and best practices.

Incorporating IEC 62382:2024 supports seamless integration with these complementary standards, enhancing overall process control system reliability and safety.

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Keywords: IEC 62382, electrical and instrumentation loop check, process industry control systems, loop check procedures, PLC loop check, DCS loop check, electrical instrumentation testing, process automation standards, control systems verification, IEC standards for process industry.

Standards Content (Sample)

IEC 62382 ®
Edition 3.0 2024-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Control systems in the process industry – Electrical and instrumentation loop
check
Systèmes de commande dans l’industrie de transformation – Contrôle de boucle
des circuits électriques et des appareillages
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IEC 62382 ®
Edition 3.0 2024-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Control systems in the process industry – Electrical and instrumentation loop

check
Systèmes de commande dans l’industrie de transformation – Contrôle de boucle

des circuits électriques et des appareillages

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040.40  ISBN 978-2-8322-9531-1

– 2 – IEC 62382:2024 © IEC 2024
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
1.1 General applicability . 7
1.2 Exclusions . 7
1.2.1 Prior and post activities . 7
1.2.2 Regulated industries . 7
1.2.3 Safety instrumented systems . 7
1.2.4 Manufacturing execution systems . 7
1.2.5 Advanced process control . 7
1.2.6 Security for industrial automation and control systems . 7
1.2.7 User-specific procedures and requirements . 8
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms . 11
4 Loop check schedule . 12
5 Loop check content . 12
5.1 Included activities . 12
5.1.1 General . 12
5.1.2 Loop check phases . 13
5.1.3 Deficiencies . 13
5.2 Excluded activities . 13
6 Loop check procedure . 14
6.1 Loop check planning . 14
6.2 Performance of loop check . 15
6.2.1 Documentation check . 15
6.2.2 Visual inspection . 15
6.2.3 Functional check prerequisites . 15
6.2.4 Functional check. 16
6.3 Additional tests – Quality and safety relevant loops . 16
6.4 Partial loop checks . 16
6.5 After completion of loop checks . 16
7 Documentation of performed loop checks . 16
7.1 Documentation . 16
7.2 Loop check results . 17
8 Quality assurance . 17
9 Safety aspects . 17
10 Loop checks post commissioning . 17
Annex A (informative) Examples of loop tests . 19
A.1 General . 19
A.2 Loop check prerequisites . 19
A.3 Measurements . 19
A.4 Actuators and valves . 20
A.5 Motor loops . 20
A.6 Alarms . 21

A.7 Diagnostics . 21
A.8 Standard loops . 21
A.9 Non-standard loops . 21
A.9.1 Loops containing intelligent devices . 21
A.9.2 Loops containing devices with network and system security . 21
A.9.3 Special loops . 21
A.9.4 Interlocks . 22
A.9.5 Quality loops . 22
A.9.6 Safety loops . 22
A.9.7 Asset management system loops . 22
A.10 Loop infrastructure . 22
A.11 E&I general concepts . 23
Annex B (informative) Loop check form . 24
Bibliography . 27

Figure 1 – Project phases and E&I testing . 12
Figure B.1 – Loop check form – Page 1 . 25
Figure B.2 – Loop check form – Page 2 . 26

– 4 – IEC 62382:2024 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CONTROL SYSTEMS IN THE PROCESS INDUSTRY –
ELECTRICAL AND INSTRUMENTATION LOOP CHECK

FOREWORD
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IEC 62382 has been prepared by subcommittee 65E: Devices and integration in enterprise
systems, of IEC technical committee 65: Industrial-process measurement, control and
automation. It is an International Standard.
This third edition cancels and replaces the second edition published in 2012. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) general re-organization of the content of the previous edition, moving informative content to
the annexes;
b) replacing the forms based on I/O type in IEC 62382:2012, Annex A to Annex E with an
example of a generic loop check form;

c) providing additional references to other applicable standards.
The text of this International Standard is based on the following documents:
Draft Report on voting
65E/1082/FDIS 65E/1114/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
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specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
– 6 – IEC 62382:2024 © IEC 2024
INTRODUCTION
The inspection and verification of the individual measurements and controls in conjunction with
the control systems used to monitor these devices is referred to as loop check. In industry,
numerous methods and philosophies are used to check the instrumentation and controls after
mechanical installation within projects for modified or new facilities.
This document was created to provide a better understanding of what loop check consists of
and also to provide a standard methodology for executing a loop check.
Annex A provides examples of checks for various loop components to aid the user in
establishing the desired loop check plans for a specific project. Annex B provides an example
of a loop check form.
CONTROL SYSTEMS IN THE PROCESS INDUSTRY –
ELECTRICAL AND INSTRUMENTATION LOOP CHECK

1 Scope
1.1 General applicability
This document defines procedures and specifications for loop check, which comprises the
activities between the completion of the loop construction (including installation and point-to-
point checks) and the beginning of cold commissioning. This document is applicable for the
construction of new plants and for expansion or retrofits (i.e. revamping) of electrical and
instrument (E&I) installations in existing plants (including PLC, DCS, panel-mounted and field
instrumentation). It does not include a detailed checkout of power distribution systems, except
as they relate to the loops being checked (i.e. a motor starter or a power supply to a four-wire
transmitter). Loop checks can be performed throughout the lifecycle of the plant. This document
is also applicable when loop checks are performed after commissioning. This document
describes what is intended to be tested but not how the test is performed, due to the wide range
of technologies and equipment available.
The intent of this document is to provide a means for all parties, including the owner, the
installer and the vendor, to clearly establish and agree on the scope of activities and
responsibilities involved in performing these tests in order to achieve a timely delivery and
acceptance of the automation system. The activities described in this document can be taken
as a guideline and adapted to the specific requirements of the process, plant or equipment.
1.2 Exclusions
1.2.1 Prior and post activities
Engineering and manufacturing activities prior to or after the loop checks, such as FAT, SAT,
SIT and commissioning, are not covered by this document.
1.2.2 Regulated industries
For applications in the pharmaceutical or other highly specialized industries, additional
guidelines (e.g. good automated manufacturing practice (GAMP)), definitions and stipulations
apply in accordance with existing standards.
1.2.3 Safety instrumented systems
All loops are checked in accordance with this document. However, loops involved in safety
instrumented systems are subjected to additional testing. The IEC 61511 series provides
requirements for checks and validation of safety instrumented systems.
1.2.4 Manufacturing execution systems
Testing and verification of manufacturing execution systems (MES) is not covered by this
document.
1.2.5 Advanced process control
Testing and verification of advanced process control (APC) are not covered by this document.
1.2.6 Security for industrial automation and control systems
The IEC 62443 series provides requirements for network and system security.

– 8 – IEC 62382:2024 © IEC 2024
1.2.7 User-specific procedures and requirements
This document does not describe any user-specific procedures and requirements that can be
related to loop check, e.g. positioning of process isolation valves, what state to leave the loop
in after check, calibration. It is the user's responsibility to ensure that these are added to the
loop check requirements as necessary.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 62381, Automation systems in the process industry – Factory acceptance test (FAT), site
acceptance test (SAT), and site integration test (SIT)
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1.1
advanced process control
APC
system comprising several tools and techniques whose common characteristic is taking process
automation beyond the limits of single-loop control
Note 1 to entry: APC includes model-based software that is used to direct the process operation and is commonly
referred to as multivariable predictive control or model predictive control.
3.1.2
asset management system
software that works with or is a feature of the BPCS and that facilitates setting and recording
of configuration, as well as display and recording of diagnostics, of instrumentation connected
to the BPCS
3.1.3
automation system
complete system for the monitoring and control of production facilities
Note 1 to entry: An automation system can include a BPCS and can also include a SIS and other subsystems.

3.1.4
basic process control system
BPCS
system which responds to input signals from the process, its associated equipment, other
programmable systems and/or operators and generates output signals causing the process and
its associated equipment to operate in the desired manner but which does not perform any SIF
Note 1 to entry: A BPCS includes all of the devices necessary to ensure that the process operates in the desired
manner.
Note 2 to entry: A BPCS typically can implement various functions such as process control functions, monitoring,
and alarms.
[SOURCE: IEC 61511-1:2016, 3.2.3]
3.1.5
basic software
software containing the graphic faceplates, base-level alarms and switch points, basic
interlocking and analogue control, at a minimum
Note 1 to entry: In the case of safety loops, any safety switch point should be included if it is not in the basic
database.
3.1.6
cold commissioning
phase, during which the activities associated with the testing and operation of equipment or
facilities using test media such as water or inert substances prior to any chemical in the system
being introduced take place
3.1.7
control system
system which responds to input signals from the process and/or from an operator and generates
output signals causing the process to operate in the desired manner
Note 1 to entry: The control system includes sensors and final elements and can be either a BPCS or a SIS or a
combination of the two.
[SOURCE: IEC 61511-1:2016, 3.2.10]
3.1.8
factory acceptance test
FAT
activity, including inspection and testing, to demonstrate that the automation system,
subsystem, or component is in accordance with the specification and is typically conducted at
the vendor's facility
3.1.9
factory integration test
FIT
activity, including inspection and testing, conducted at the vendor's facility to demonstrate that
the merging of some or all of the various subsystems and components into one overall
automation system functions in accordance with the specification
3.1.10
function diagram
graphical description of the E&I functions of the control system
Note 1 to entry: Refer to IEC 62708 and the IEC 61131 series.

– 10 – IEC 62382:2024 © IEC 2024
3.1.11
functional requirements specification
specification listing the detailed operational requirements for a control system (i.e. what the
system does, not how it does it)
3.1.12
hot commissioning
phase during which the activities associated with the testing and operation of equipment or
facilities using the actual chemical process prior to making an actual production run take place
3.1.13
installer
company that will install or has installed the automation system, subsystem, or component on
site
3.1.14
instrument specification
data sheet with all essential E&I data concerning tagging, function, description, measuring
range, accuracy, location, process data, instrument data, etc.
Note 1 to entry: Refer to ISA-TR20.00.01 for examples of instrument specifications.
3.1.15
loop
all the hardware and software necessary to work together for the measurement or
communication or control, or a combination thereof, of a process variable
Note 1 to entry: The loop consists of all associated components and functions including sensor, logic, control,
actuator, and HMI.
3.1.16
loop diagram
representation of hardware or basic software functions, or both, of a control loop with graphical
symbols
Note 1 to entry: A loop diagram shows equipment in its topological order and wiring including the terminals.
Note 2 to entry: Refer to IEC 62708 and ISA-5.4.
3.1.17
loop list
tabulation of all loops with tagging, function, service description, and PID reference
3.1.18
owner
company that operates the production facilities where the automation system is or will be
installed
3.1.19
precommissioning
phase, during which the activities of non-operating adjustments, cold alignment checks,
cleaning, and testing of machinery take place

3.1.20
safety instrumented system
SIS
instrumented system used to implement one or more SIFs
Note 1 to entry: A SIS is composed of any combination of sensor(s), logic solver(s), and final element(s) (e.g. see
IEC 61511-1:2016, Figure 6). It also includes communication and ancillary equipment (e.g. cables, tubing, power
supply, impulse lines, heat tracing).
Note 2 to entry: A SIS can include software.
Note 3 to entry: A SIS can include human action as part of a SIF.
[SOURCE: IEC 61511-1:2016, 3.2.67, modified – In Note 3 to entry, Figure 6 and the reference
to ISA TR84.00.04:2015, part 1 have been omitted.]
3.1.21
site acceptance test
SAT
activity, including inspection and testing, conducted at the site of the installation, to demonstrate
that the installation of the automation system, any subsystem, or any component is in
accordance with the applicable standards, codes, specifications, and installation instructions
3.1.22
site integration test
SIT
activity, including inspection and testing, conducted at the site of the installation, to demonstrate
that the merging of the various subsystems and components into one overall automation system
is completed and that all components work together in accordance with the specification
3.1.23
start-up
milestone marking the end of cold commissioning and formally setting process equipment into
operation leading into production
3.1.24
vendor
manufacturer, distributor, or systems integrator of the automation system, subsystem, or
component
3.2 Abbreviated terms
The following abbreviated terms are used (for terms not otherwise defined):
DCS distributed control system
E&I electrical and instrumentation
HART highway addressable remote transducer
HMI human machine interface
HVAC heating, ventilation and air conditioning
I/O input and output
MCC motor control centre
P&ID piping (or process) and instrument diagram
PLC programmable logic controller
SIF safety instrumented function

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4 Loop check schedule
Loop checks are performed to verify the proper operation of all loops prior to the commissioning
of a new plant or plant modification. They follow the installation of all the loop components and
the functionality checks of the control system after field installation. These functionality checks
shall be performed in accordance with IEC 62381. The loop checks will ideally occur in the
precommissioning phase of the schedule.
However, normal occurrence is that the loop checks begin when any specific loop is completed
and determined to be ready for check even if it is during the construction phase. The owner or
owner's designated representative shall determine prerequisites prior to beginning a loop
check. The loop check can substantially overlap the construction phase.
Loop checks are the last systematic check of a control system to ensure that:
• all loop documents (loop diagrams, loop check sheets, etc.) are current and available;
• all instrumentation and equipment have been delivered according to the design
specifications;
• the installation has occurred in accordance with engineering documents; and
• all loops function as required.
The proper operation of all loops shall be verified prior to proceeding to the commissioning
phase of the project. The loop checks are the quality check of the engineering design; the
delivered instrumentation and associated equipment; and their installation. The main loop-
related activities in the commissioning phase following loop check are loop tuning and
verification of all other loop operations and control schemes.
Figure 1 provides a general illustration of a portion of the timeline of a project from construction
to production, where the control system checks described in IEC 62381 and the loop checks
described in this document occur. The industry and the specifics of a project can vary the
relative timing of each test.
Figure 1 – Project phases and E&I testing
5 Loop check content
5.1 Included activities
5.1.1 General
The loop check includes the following elements of a loop.
• Hardware components – check the functionality and interoperability of:
– all loop components, located in the field, control room, or other rooms (e.g. rack
room), their configuration and their interconnection;
– input and output cards of the control system; and
– connections of the loop to other systems.

• Software – check the configuration and functionality of:
– faceplate and graphics;
– alarms, including range and setpoint for analogue alarms and actuation for all alarms
in accordance with the alarm list;
– control (correct control algorithm configured, direct or reverse setting); and
– interlocking.
The loop check uses the basic graphics and faceplates of the control system. Inputs and outputs
can be connected not only to the BPCS but also to the SIS or other subsystems. They all are
monitored and displayed to the operator on the BPCS.
5.1.2 Loop check phases
The actual loop check involves the three following phases (see details in Clause 6).
• Documentation check
Check for the completeness and consistency of loop documents, including any
documents from the installation or FAT.
• Installation check
Visual inspection of loop devices for correct installation and tagging.
• Functional check
All loop components (hardware and software) are checked for proper configuration and
operation.
5.1.3 Deficiencies
During the loop check, the following three types of deficiencies can be found.
• Installation failures
Discrepancies with the specified hardware or the installation (incorrect installation,
incorrect instruments, etc.). The installer should resolve these problems.
• Configuration failures
Discrepancies between the software configuration and the software functional
specification. The entity responsible for the control system programming should resolve
these problems.
• Engineering and design failures
Discrepancies to be suspected when, despite installation of the designated instruments
in accordance with the applicable drawings, the desired functionality cannot be realized
(e.g. due to an incorrect drawing, specification, etc.). The entity responsible for the
engineering on the project should resolve these problems.
Additional deficiencies can be in the process design, but this can only be determined after
process start-up.
5.2 Excluded activities
The loop check does not include the following activities.
• test activities possible without construction being completed:
– software testing using simulation tools; and
– other factory acceptance tests performed at the vendor’s or other’s facilities;
• other software checkout activities (FAT, etc.);

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• detailed construction and mechanical inspections performed during the construction
phase:
– cable testing during construction (Hipot, Meggering, etc.); and
– point-to-point wiring checks;
• testing of the internal workings of package units (i.e. process subunits, machinery,
complex analysers, etc.);
NOTE Only the I/O testing of this equipment is included in the loop check.
• validation of safety instrumented systems;
• testing of network and system security;
• manufacturing execution systems, advanced process control, testing for regulated
industries;
• activities belonging to the commissioning phase: tuning of loops, instrument and control
schemes (e.g. calibrating of level transmitters by filling tanks; verification of complex
control schemes; tuning of continuous control schemes).
6 Loop check procedure
6.1 Loop check planning
Loop check planning begins with a complete list of all loops to be checked. These can be newly
installed loops or existing loops that are being modified. The test(s) to be performed on each
loop and the acceptance criteria shall then be established. Annex A provides some examples
of loop tests that can assist the user in developing a specific loop test plan for the loops on the
project.
All associated documentation for the loops to be checked should be assembled. This can
include items listed below:
• instrument index providing pertinent information for all instruments;
• loop list;
• P&ID drawings for the project;
• functional requirements specification;
• function diagrams (single- or multi-loop);
• instrument and equipment location plans;
• for each instrument loop to be checked:
– loop diagram;
– instrument calibration document;
– instrument specification sheet for each device in the loop; and
– loop check sheet to document the checks;
• for each motor loop:
– loop diagram;
– motor elementary, single line diagram, power and control plan;
– loop check sheet to document the checks; and
– completed motor check sheets documenting motor installation checks performed;
• BPCS interlock list with detailed interlock descriptions and trip settings; and
• BPCS alarm list with all alarm settings and actions.

If loop checks will require the involvement or assistance of a specialist (e.g. vendor
representative for an equipment package or specialty component), prior arrangements should
be made for that person’s participation in the loop checks.
6.2 Performance of loop check
6.2.1 Documentation check
The documentation check consists of the following activities.
• The checkout of the loop shall first establish that all documentation pertaining to that
loop is available and consistent. If the loop is one to be given special attention or
significance (e.g. a safety, quality, environmental, or other), the documentation for that
loop should be correctly labelled or identified accordingly.
• The pertinent documentation shall, as a minimum, contain a loop diagram and a
specification containing all calibration and functional data necessary to verify the correct
operation of the loop.
6.2.2 Visual inspection
The visual inspection consists of the following activities.
The installation of each loop component shall be visually checked against the documents to
ensure that the correct instruments were installed and that the installation is in accordance with
the hardware specifications and installation drawings. Visual checks shall include the following:
• valves and flowmeters are checked for correct installation with the direction of flow;
• local instrumentation can be easily read;
• all the elements of the loop are available, accessible, labelled and installed in a clean
and neat manner (including cables, wires, junction boxes, panels, cabinets, racks),
considering their maintenance;
• component and wire tagging is clear, readable, and unambiguous (no danger of false
interpretation);
• field elements are adequately protected from mechanical or environmental damage; and
• if a model exists, check the location of the instrument against the model.
The following supporting infrastructure shall also be visually checked for completeness and
correctness of installation, including properly installed and labelled:
• junction boxes, panels, cabinets, racks, and all wiring terminations;
• instrument piping and tubing;
• instrument air supply;
• utility power and power supplies; and
• wired and wireless networks.
6.2.3 Functional check prerequisites
Any problems found affecting loop performance shall be resolved prior to powering the loop and
performing loop checks. Prior to performing loop checks, the latest firmware and configuration
shall be downloaded to intelligent devices and the BPCS, SIS, or other system involved in loop
check shall be installed and its SAT completed. Any open items from previous checks that can
affect loop performance shall be resolved. Calibration of all devices in the loop shall be
completed prior to performing loop checks.

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6.2.4 Functional check
The functional checks of loops can be performed in logical groupings (e.g. by process area or
by control system termination rack) or as they become available after their installation. The
actual method and order of checkout should be defined by the project team prior to starting the
loop check.
The purpose of the functional check is to exercise all components of a loop during one test and
verify their individual and combined proper operation. Checking a loop in pieces does not qualify
as a loop functional check and shall not substitute for the loop functional check.
During the functional check of a loop, checks shall be made of each component’s operation
under fail conditions: does the component’s action on failure meet the required component fail-
safe action and does the loop’s action on failure of any component meet the required loop fail-
safe action?
6.3 Additional tests – Quality and safety relevant loops
All loops that are identified by the owner as quality-relevant (important to production quality)
and safety-measure-relevant (important to safety) loops should be rechecked after successful
completion of the loop check as a double check for proper operation. This check should also
be performed on the loop and all its components and be performed by different people than who
performed the initial check.
6.4 Partial loop checks
All components of a loop shall be tested together to confirm proper operation of the loop. Owing
to project deliveries or other schedule issues, it can be decided to test a loop in segments via
two or more partial loop tests, in order to identify problems or confirm operation. This approach
can be used but does not replace the requirement to test all components of a loop together
before that loop is placed in service.
Traditionally, these tests are performed using manual methods. With modern systems and test
equipment, some of these tests can also be performed using automated methods, depending
on the equipment’s capability. If automated methods are used, it is the responsibility of the
entity performing the tests to demonstrate that the automated tests completely cover all aspects
of the automated portion of the test plan and are validated.
6.5 After completion of loop checks
The final state of each loop after completing loop check shall be secured to ensure that there
are no modifications or subsequent interventions in the hardware or software. A complete
recheck shall be required for any loop that has been modified (hardware or software) or
disconnected after successful loop checks have been completed.
7 Documentation of performed loop checks
7.1 Documentation
Documentation of performed loop checks should include the following as a minimum.
• Loop check sheets – The results of each loop check shall be completely documented on
a loop check sheet intended for that purpose. Annex B provides an example of a loop
check sheet that can be used for various loops. Setup and configuration of loop
components should a
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