ISO/DIS 18436-9

Condition Monitoring and Diagnostics of Machine Systems — Requirements for training and certification of personnel — Part 9: Optical Gas Imaging

This document reflects on the qualification of personnel performing Optical Gas Imaging (OGI) for fugitive emissions. The intention is to add a sub-category to ISO 18436 for this specific purpose as OGI requires a set of skills that is different than the traditional infrared condition monitoring. The skill set includes many similarities between traditional condition monitoring, such as system and component knowledge, but differs in that the user must recognize the conditions for successful gas imaging. Knowledge of Chemistry is essential as well as detector Physics to determine the proper wavelength instrument. The document is intended for end users, contractors, consultants, service providers and manufacturers.

Titre manque — Partie 9: Titre manque

General Information

• Status: Not Published
• ICS: 03.100.30 - Management of human resources
• ICS: 13.320 - Alarm and warning systems
• ICS: 17.180.01 - Optics and optical measurements in general
• Technical Committee: ISO/TC 108/SC 5 - Condition monitoring and diagnostics of machine systems
• Drafting Committee: ISO/TC 108/SC 5/WG 7 - Training and accreditation in the field of condition monitoring and diagnostics
• Current Stage: 4099 - Full report circulated: DIS approved for registration as FDIS
• Start Date: 12-Oct-2025
• Completion Date: 27-Jun-2026

Overview

ISO/DIS 18436-9 is an international draft standard from ISO that specifies requirements for the training and certification of personnel involved in Optical Gas Imaging (OGI) for the detection of fugitive emissions. This document is part of the ISO 18436 series, which addresses condition monitoring and diagnostics of machine systems, and it establishes a distinct protocol for qualifying professionals who conduct OGI, recognizing that this technique demands specialized skills beyond those used in traditional infrared thermography.

OGI is a critical non-contact method for identifying invisible gas leaks-such as hydrocarbons, ammonia, sulfur hexafluoride, carbon monoxide, and various refrigerants-in industrial settings. This standard provides a framework for organizations, end users, contractors, consultants, service providers, and equipment manufacturers to ensure that OGI practices are competent, reliable, and aligned with regulatory and operational needs.

Key Topics

• Qualification and Certification Categories:
  The standard defines three certification categories (I, II, III), each with ascending requirements for knowledge, skills, and responsibilities related to OGI inspection, analysis, and program management.

• Training and Experience Requirements:
  Comprehensive guidelines cover minimum required education, practical experience, and training durations for each certification level, ensuring personnel have the essential background in system knowledge, chemistry, and detector physics.

• Examination and Assessment:
  The standard outlines the structure of written and practical exams by category, including minimum question counts, passing grades, and core topic coverage to verify candidate competence in OGI.

• Core OGI Competencies:
  Personnel must demonstrate proficiency in using various OGI equipment, understanding imaging techniques, assessing environmental conditions, performing safety checks, and interpreting detection results under real-world operating conditions.

• Regulatory and Safety Compliance:
  Adherence to local, national, and international safety and regulatory guidelines is emphasized, especially for specialized scenarios like aerial platform use (e.g., small Unmanned Aerial Systems, or sUAS).

Applications

• Industrial Leak Detection:
  OGI is widely applied in oil and gas, petrochemical, power generation, and chemical processing industries to visually detect and document gas leaks, helping organizations manage emissions, ensure safety, and comply with environmental regulations.

• Environmental Emissions Management:
  By enabling early identification of fugitive emissions, certified OGI professionals help organizations minimize environmental impact and meet regulatory reporting requirements under programs such as LDAR (Leak Detection and Repair).

• Operational Efficiency:
  Certified OGI inspectors support asset integrity by identifying leaks that can compromise equipment efficiency or safety, reducing unplanned downtime and maintenance costs.

• Aerial Inspections:
  The standard addresses supplementary skills for conducting OGI with drones or sUAS, expanding inspection reach and efficiency, particularly for hard-to-access or hazardous locations.

Related Standards

• ISO 18436-1: Condition Monitoring and Diagnostics of Machine Systems - Requirements for certification of personnel
• ISO 13372: Condition Monitoring and Diagnostics of Machines - Vocabulary
• ISO/IEC 17000: Conformity Assessment - Vocabulary and General Principles
• ISO/IEC/ASNT Recommended Practice SNT-TC-1A: Personnel Qualification and Certification in Nondestructive Testing (for visual acuity assessment)

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Keywords: ISO 18436-9, optical gas imaging standard, OGI certification, fugitive emissions detection, condition monitoring, machine diagnostics, personnel qualification, environmental compliance, non-destructive testing, industrial gas leak detection.

Standards Content (Sample)

DRAFT
International
Standard
ISO/DIS 18436-9
ISO/TC 108/SC 5
Condition Monitoring and
Secretariat: SA
Diagnostics of Machine Systems —
Voting begins on:
Requirements for training and
2025-07-17
certification of personnel —
Voting terminates on:
2025-10-09
Part 9:
Optical Gas Imaging
ICS: 17.180.01; 13.320; 03.100.30
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
This document is circulated as received from the committee secretariat.
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
DRAFT
International
Standard
ISO/DIS 18436-9
ISO/TC 108/SC 5
Condition Monitoring and
Secretariat: SA
Diagnostics of Machine Systems —
Voting begins on:
Requirements for training and
certification of personnel —
Voting terminates on:
Part 9:
Optical Gas Imaging
ICS: 17.180.01; 13.320; 03.100.30
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
This document is circulated as received from the committee secretariat. BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: [phone]
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Certification of Personnel . 1
4.1 General .1
4.2 Category I .2
4.3 Category II .2
4.4 Category III .3
5 Eligibility . 3
5.1 General .3
5.2 Education .3
5.3 Training .4
5.3.1 Introduction .4
5.3.2 Training for supplementary certification .4
5.4 Experience .4
6 Examinations . 5
6.1 Examination content .5
6.2 Conduct of examinations .6
Annex A (normative) Examination content and training syllabus . 7

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 18436-1 was prepared by Technical Committee ISO/TC 108, Mechanical vibration, shock and condition
monitoring, Subcommittee SC 5, Condition monitoring and diagnostics of machine systems.
The document ASNT Recommended Practice SNT-TC1A (2024), “Personnel Qualification and Certification in
Nondestructive Testing” was used as a reference for testing the visual acuity of candidates.

iv
DRAFT International Standard ISO/DIS 18436-9:2025(en)
Condition Monitoring and Diagnostics of Machine Systems —
Requirements for training and certification of personnel —
Part 9:
Optical Gas Imaging
1 Scope
This part of ISO 18436 specifies sector specific requirements for organizations (certification bodies)
operating conformity assessment systems who perform Optical Gas Imaging inspections to identify fugitive
emissions (e.g, but not limited to, hydrocarbons, ammonia, sulphur hexafluoride, carbon monoxide, carbon
dioxide, refrigerants) and who may recommend corrective action.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 13372, Condition monitoring and diagnostics of machines — Vocabulary
ISO/IEC 17000:2004, Conformity assessment — Vocabulary and general principles
ISO 18436-1, Condition monitoring and diagnostics of machine systems — Requirements for certification of
personnel — Part 1: Sector specific requirements for certification bodies and the certification process
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 17000, and ISO 18436-1 apply.
sUAS when referenced in this document, refers to small Unmanned Aerial Systems.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Certification of Personnel
4.1 General
Certified persons are not only to have the knowledge areas covered in Annex A & B shall have the knowledge,
skills, and aptitude to adequately perform the job tasks for the appropriate categories as indicated in
clauses 4.2, 4.3, and 4.4.
4.2 Category I
Individuals certified to Category I can perform Optical Gas Imaging according to established and recognized
procedures. Personnel certified to Category I shall be able to:
a) apply a specified optical gas imaging technique (e.g. utilize enhanced gas detection mode);
b) set up and operate the optical gas imaging equipment needed for safe data collection (e.g. fixed, portable
or aerial platforms);
c) identify, prevent and control poor data collection and potential error sources;
d) identify and follow an established inspection route;
e) identify gas leaks and fugitive emissions using established instructions;
f) record and document gas leaks and fugitive emissions using established instructions;
g) record and document the environmental conditions at the time of the test (e.g. ambient air temperature,
humidity, wind speed and direction;
h) verify that the background temperature (ΔT ) at the time of the inspection is suitable for obtaining
good data;
i) adjust the image as needed to highlight the gas leak/fugitive emission;
j) select an appropriate optical gas imaging mode (e.g. auto, manual, enhanced) for successful gas
detection;
k) perform instrument verification check as required by established instructions and/or regulatory
requirements;
l) perform any required optical gas imaging camera maintenance (e.g. camera body and lens cleaning) to
ensure successful emission detection;
m) report inspection results;
n) comply with all appropriate safety protocols;
o) comply with all local and national regulations regarding aerial platforms.
4.3 Category II
Individuals certified to Category II can perform optical gas imaging according to established and recognized
procedures. Personnel certified to Category II shall be able to perform all the duties of a Category I and shall
be able to:
a) determine the type of gas/fugitive emission that may be leaking;
b) analyse gas absorption/transmission curves or gas response factors and select the appropriate optical
gas imaging camera;
c) create safe inspection routes that assure 100 % inspection coverage;
d) identify and document difficult to monitor (DTM) and impossible to monitor (ITM) components prior to
and/or during an inspection;
e) locate/identify/quantify the source of the gas leak/fugitive emission;
f) maintain the calibration of the optical gas imaging equipment based on the manufacturer’s
recommendations;
g) measure emissivity and reflective background per established techniques;

h) measure temperatures of components as required by established techniques;
i) establish the minimum and maximum safe altitudes for aerial platforms;
j) prepare inspection reports;
k) maintain a database of inspection results; and
l) provide guidance to and supervise Category I.
4.4 Category III
Individuals certified as Category III can perform optical gas imaging according to established and recognized
procedures. Personnel certified to Category III shall be able to perform all the duties of a Category II and
shall be able to:
a) develop and establish Optical Gas Imaging inspection programs, write inspection procedures and
instructions, determine frequency of testing, identify systems/components for periodic/continuous
monitoring and the use of advanced detection techniques;
b) assess the severity and compare to established acceptance criteria;
c) interpret and provide leak quantification calculations as required;
d) interpret and evaluate codes, standards, specifications, regulations and procedures;
e) designate the inspection methods, procedures and instructions to be used;
f) provide guidance and supervise Category I and II personnel;
g) recommend the use of alternative or supplemental leak detection technologies;
h) be able to establish and manage leak detection programs;
i) develop and implement Optical Gas Imaging inspection safety protocols.
NOTE It is the employer’s responsibility to ensure Category III personnel have the necessary competency in the
required management skill, for example creating budgets, preparing cost justifications, and managing personnel
development as required.
5 Eligibility
5.1 General
Candidates should have a combination of education, training, and experience to ensure that they understand
the principles and procedures applicable to optical gas leak detection and analysis.
It is advised that all candidates have their colour perception assessed by the Ishihara 24 plate test. A record
of test results should be retained and presented to the assessment body upon request. In the event of a color
perception deficiency, indicated by misreading four or more of the 24 plates is detected during the Ishihara
test, a further “task specific” test is to be carried out by an appropriate entity. Failure to pass this test may
require the candidate to use a monochrome palette. This “task specific” test and any requirements to use a
monochrome palette is to be documented and made available to the assessment body upon request.
5.2 Education
Candidates seeking certification do not need to provide evidence of formal education to establish eligibility.
However, it is recommended that candidates for Category I and Category II have at least a secondary
school graduate certification or its equivalent. Category II and III candidates shall be able to manipulate
simple algebraic equations, use a basic scientific calculator and be familiar with the operation of personal
computers. Successful completion of two or more years of mechanical technology, mechanical engineering,

chemical engineering or petroleum engineering at an accredited college, university or technical school is
highly recommended for candidates seeking certification to Category III.
5.3 Training
5.3.1 Introduction
To be eligible to apply for certification based on this part of ISO 18436, the candidates shall provide evidence
of successful completion of training based on the requirements of Annex A. The documents listed in the
Bibliography should be used as the domain of knowledge for the training syllabus. Such training shall be
compliant with ISO 18436-3. The minimum duration of training is shown in Table 1. Training should be
in the form of lectures, demonstrations, practical exercises, or formal training courses. Certification
requirements shall be in accordance with this part of ISO 18436. Training time devoted to each subject shall
be in accordance with Annex A and Table 1. See Annex B for a non-exhaustive list of the topics and subtopics
to be covered. The curriculum may be adjusted for specific applications (buildings, sUAS, electrical, etc.) if
the total hours and broad subject matters are covered.
Table 1 — Minimum duration of cumulative training (hours)
Category I Category II Category III
24 48 72
Training may be modularized into two or more subject areas covering general scientific principles and
application-specific knowledge to allow for mutual recognition between non-destructive testing, condition
monitoring and optical gas imaging bodies.
5.3.2 Training for supplementary certification
The operation of small unmanned aerial systems (sUAS) for optical gas imaging requires unique skills and
knowledge. Supplementary training in the operation of such systems should include selection of the proper
payload; scanning speed, height above ground level for imaging, height above ground level for measurement,
proper sUAS positioning to minimize solar reflections, ability to recognize solar loading and competency in
local sUAS regulations, including any needed licensing.
5.4 Experience
To be eligible to apply for assessment based on this part of ISO 18436, the candidate shall provide evidence
to the ISO 18436-1 certification and body of experience in the field of Optical Gas Imaging in accordance
with Table 2. Certification to Category II and III requires previous certification at the lower category.
Table 2 — Minimum cumulative practical, interpretation and program management experience
requirements (months)
Category I Category II Category III
12 months 24 months 36 months
NOTE: The experience hours are based on 16 hours minimum per month of optical gas imaging experience in accordance with
clauses 4 and 5.
5.4.1 The minimum total experience durations specified (in months) are required to enable the acquisition
of experience in all category criteria in accordance with ISO 18436-1 and clause 5.4.
5.4.2 Candidates shall keep verifiable documentary evidence of hours and nature of work for their Optical
Gas Imaging inspections and reporting in accordance with ISO 18436-1. Candidates for Categories I and II
shall have this evidence validated by a Category II or III person or, in the absence of such a person, by the
candidate’s technical supervisor.

5.4.3 Candidates for Category III shall have this evidence validated by a Category III person or, in the
absence of such a person, by the candidate’s technical supervisor.
5.4.4 The validation for all categories requires the signature of the validating person on the documentary
evidence. The validating person should augment this validation process via oral assessment, accompanied
task performance, report submission and review, procedure submission and review or a combination
thereof, to increase the confidence of the validation.
6 Examinations
6.1 Examination content
6.1.1 For each Category, candidates shall be required to answer a fixed minimum number of multiple-
choice questions in a specified time duration as indicated by Table 3.
6.1.2 Questions shall be of a practical nature yet test the candidate on concepts and principles required to
conduct Optical Gas Imaging on components.
6.1.3 The examination for Category I shall consist of a Part A — General Theory and a Part B — Practical
Application. The Part B examination shall cover quality data acquisition, the recognition, prevention and
control of error sources and basic leak detection. This examination may include physical data acquisition
tasks in addition to image interpretation.
6.1.4 The examination for Category II shall consist of a Part A — General Theory (50 %) and a Part B —
Practical Application (50 %). The Part B shall cover detector types, sensor selection, image analysis image
interpretation and quantification. This examination may include both physical data acquisition tasks in
addition to image interpretation and analysis.
6.1.5 The examination for Category III shall consist of a Part A — General Theory (50 %) and a Part B
— Practical Application (50 %). The Part B shall cover component operation (tanks, valves, separators,
wells, compressors, controllers, flares), leak verification methods, leak quantification methods, inspection
procedure development and program development. Part B may also include narrative and short answer
questions. Some questions shall involve the interpretation of thermal images and/o
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