prEN ISO 19277-1

Oil and gas industries including lower carbon energy - Qualification testing and acceptance criteria for protective coating systems under insulation - Part 1: Liquid applied coatings (ISO/DIS 19277-1:2026)

This document describes various corrosion under insulation (CUI) environments in refineries and other related industries and environments, and establishes CUI environmental categories including operating temperature ranges from −45 °C to 204 °C for topside and aboveground service only. This document specifies both established and other test methods for the assessment of coatings used for prevention of CUI for each given environment. This document also provides acceptance criteria for each CUI environment.
NOTE The test results and acceptance criteria can be considered an aid in the selection of suitable coating systems. For service or peak temperatures below −45 °C an optional cryogenic test can be incorporated and for over 204 °C testing acceptance criteria can be agreed between interested parties. Additional or other test and acceptance measures are possible, but require particular agreement between the interested parties.
This document covers spray-applied coatings applied on new carbon and austenitic stainless steel for use in CUI service. This document does not cover testing of sacrificial coatings, such as inorganic zinc, as these coatings can be consumed quickly in wet environments. Developing accelerated corrosion testing for what can be continuous wet service with sacrificial coatings is beyond the scope of this document.
"Non-through porosity" thermal spray aluminium coatings with greater than 250 µm dry film thickness can be tested and qualified in accordance with this document. This document does not cover tape and sheet applied products for use in preventing CUI.
This document does not deal with other aspects of coating degradation, such as those caused by abrasion, erosion, ultraviolet degradation or other methods that can exist given specific environment and construction methods.

Öl- und Gasindustrie einschließlich kohlenstoffarmer Energieträger - Qualifikationsprüfung für Schutzbeschichtungssysteme unter Isolierungen - Teil 1: Flüssige Beschichtungen (ISO/DIS 19277-1:2026)

Industries du pétrole et du gaz, y compris les énergies à faible teneur en carbone - Essais de qualification des systèmes de revêtement protecteurs sous isolation - Partie 1: Revêtements appliqués sous forme liquide (ISO/DIS 19277-1:2026)

Naftna in plinska industrija, vključno z nizkoogljično energijo - Preskušanje primernosti in sprejeta merila za zaščitne premazne sisteme pod izolacijo - 1. del: Tekoči premazi (ISO/DIS 19277-1:2026)

General Information

• Status: Not Published
• Publication Date: 23-Aug-2027
• ICS: 75.200 - Petroleum products and natural gas handling equipment
• ICS: 87.040 - Paints and varnishes
• Technical Committee: CEN/TC 12 - Materials, equipment and offshore structures for petroleum and natural gas industries
• Drafting Committee: CEN/TC 12 - Materials, equipment and offshore structures for petroleum and natural gas industries
• Current Stage: 4060 - Closure of enquiry - Enquiry
• Start Date: 20-Apr-2026
• Completion Date: 20-Apr-2026
• Ref Project: oSIST prEN ISO 19277-1:2026 - Oil and gas industries including lower carbon energy - Qualification testing and acceptance criteria for protective coating systems under insulation - Part 1: Liquid applied coatings (ISO/DIS 19277-1:2026)

Relations

• Referred By: EN ISO 29461-4:2025 - Air intake filter systems for rotary machinery - Part 4: Test methods for static filter systems in coastal and offshore environments (ISO 29461-4:2025)
• Effective Date: 28-Jan-2026
• Revises: EN ISO 19277:2018 - Petroleum, petrochemical and natural gas industries - Qualification testing and acceptance criteria for protective coating systems under insulation (ISO 19277:2018)
• Effective Date: 26-Nov-2025

Overview

prEN ISO 19277-1:2026 sets out standardized methods for qualification testing and acceptance criteria for protective liquid applied coating systems used under insulation within the oil and gas industries, including lower carbon energy sectors. Focused on topside and above-ground equipment operating from −45 °C to 204 °C, this European Standard provides robust guidance on assessing coatings designed to prevent corrosion under insulation (CUI) in refineries and related industrial environments. It details relevant test methods and establishes environmental categories to ensure reliable and long-lasting corrosion protection.

Key Topics

• CUI Environment Categories: The standard defines specific CUI classes based on operational temperature ranges (CUI-1, CUI-2, CUI-3), ensuring coatings are qualified for their intended thermal exposure.
• Testing and Acceptance: It identifies laboratory and field test protocols to simulate environmental and operational stresses, including:
  • Artificial ageing and thermal cycling
  • Multi-phase cyclic corrosion tests
  • Specific adhesion and durability assessments
• Coating Application & Qualification: The document outlines the procedures for coating application, curing, thickness measurement, and conditioning-supporting consistency in product evaluation.
• Test Specimens and Sampling: Standardizes requirements for substrate preparation, specimen sizes, and the number of samples to improve comparability.
• Limits of Scope: The standard applies only to spray-applied liquid coatings, tested primarily on new carbon and austenitic stainless steel for above ground insulated equipment. It excludes sacrificial coatings like inorganic zinc and does not address degradation from abrasion, erosion, or UV exposure.

Applications

prEN ISO 19277-1:2026 delivers clear value in supporting safer, more cost-effective infrastructure management within industries prone to corrosion under insulation. Key applications include:

• Oil and Gas Refineries: Provides a framework for qualifying and selecting CUI-resistant coatings for equipment insulation, minimizing risk of undetected corrosion, unexpected failures, and safety incidents.
• Natural Gas Processing: Used for protecting insulated process piping and vessels operating under a wide range of service temperatures.
• Lower Carbon Energy Projects: Adapts to evolving asset integrity needs in renewable energy and carbon reduction initiatives by offering standards applicable to new technology and processes.
• Coating Manufacturers & Specifiers: Assists in product development and verification, ensuring coatings are fit for service and meet industry and client expectations.
• Maintenance and Inspection: Supports informed decision-making for asset owners, inspectors, and service providers tasked with maintaining coating integrity and ensuring regulatory compliance.
• Engineering Consultancies: Provides a reference for equipment designers and consultants when specifying protective coatings for new builds or retrofits.

Related Standards

For robust corrosion protection and compliance, prEN ISO 19277-1:2026 should be considered alongside the following standards:

• ISO 12944-6 - Corrosion protection of steel structures by protective paint systems - Laboratory performance test methods
• ISO 9227 - Corrosion tests in artificial atmospheres - Salt spray tests
• ISO 4628 series - Methods for assessing coating degradation (blistering, cracking, flaking, rusting, delamination)
• AMPP TM 21442-2023 - Test method for evaluation of protective coatings for use under insulation
• ISO 19840 & ISO 15528 - Measurement and sampling of coating thickness and materials
• ISO 1513 - Preparation and examination of test samples before evaluation

Conclusion

prEN ISO 19277-1:2026 delivers robust, consistent guidance for evaluating liquid applied coatings under insulation, helping the oil, gas, and energy industries mitigate CUI risk. This standard promotes confident coating selection, qualification, and maintenance strategies, ultimately supporting longer asset life, improved operational safety, and reduced total lifecycle costs. Asset owners, specifiers, and coating suppliers benefit from a trusted and harmonized reference when tackling the challenges of corrosion under insulation.

Standards Content (Sample)

SLOVENSKI STANDARD
01-april-2026
Naftna in plinska industrija, vključno z nizkoogljično energijo - Preskušanje
primernosti in sprejeta merila za zaščitne premazne sisteme pod izolacijo - 1. del:
Tekoči premazi (ISO/DIS 19277-1:2026)
Oil and gas industries including lower carbon energy - Qualification testing and
acceptance criteria for protective coating systems under insulation - Part 1: Liquid
applied coatings (ISO/DIS 19277-1:2026)
Öl- und Gasindustrie einschließlich kohlenstoffarmer Energieträger -
Qualifikationsprüfung für Schutzbeschichtungssysteme unter Isolierungen - Teil 1:
Flüssige Beschichtungen (ISO/DIS 19277-1:2026)
Industries du pétrole et du gaz, y compris les énergies à faible teneur en carbone -
Essais de qualification des systèmes de revêtement protecteurs sous isolation - Partie 1:
Revêtements appliqués sous forme liquide (ISO/DIS 19277-1:2026)
Ta slovenski standard je istoveten z: prEN ISO 19277-1
ICS:
75.200 Oprema za skladiščenje Petroleum products and
nafte, naftnih proizvodov in natural gas handling
zemeljskega plina equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 19277-1
ISO/TC 67
Oil and gas industries including
Secretariat: NEN
lower carbon energ — Qualification
Voting begins on:
testing and acceptance criteria for
2026-01-26
protective coating systems under
Voting terminates on:
insulation —
2026-04-20
Part 1:
Liquid applied coatings
Industries du pétrole et du gaz, y compris les énergies à faible
teneur en carbone — Essais de qualification des systèmes de
revêtement protecteurs sous isolation —
Partie 1: Revêtements appliqués sous forme liquide
ICS: 87.040; 75.200
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.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
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
ISO/DIS 19277-1:2026(en)
ISO/DIS 19277-1:2026(en)
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: [phone]
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Website: www.iso.org
Published in Switzerland
ii
ISO/DIS 19277-1:2026(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Performance testing design . 3
4.1 Relationship between artificial testing and natural exposure .3
4.2 Laboratory tests .3
4.3 Additional laboratory tests .4
5 CUI classification environments . 4
6 Test specimens . 4
6.1 Test specimens’ requirement .4
6.2 Steel substrates .4
6.2.1 Artificial Ageing and Thermal Cycling tests .4
6.2.2 Method A- Multi-Phase CUI cyclic corrosion test .4
6.2.3 Method B - Vertical Pipe Test .5
6.2.4 Method C – Test procedure as per AMPP TM21442-2023 . .5
6.3 Sampling of coatings.5
6.4 Number of test specimens .5
6.5 Coating systems .5
6.5.1 Coating application .5
6.5.2 Dry film thickness .5
6.5.3 Overcoating interval .6
6.5.4 Conditioning .6
6.5.5 Heat conditioning.6
6.6 Scribe .6
6.7 Reference system .6
7 Test procedures and assessment . . 6
7.1 Assessment and acceptance .6
7.2 Assessment of adhesion and artificial ageing .6
7.2.1 Adhesion testing before artificial ageing .6
7.2.2 Artificial ageing .7
7.2.3 Adhesion testing after artificial ageing .7
7.3 Thermal cycling test .8
7.4 Method A - Multi-phase CUI cyclic corrosion test .8
7.4.1 Description of test .8
7.4.2 Test equipment-apparatus .8
7.4.3 Test set-up and preparation .11
7.4.4 Test procedure. 12
7.4.5 Acceptance . 13
7.5 Method B - Vertical Pipe Test . 13
7.5.1 Application . 13
7.5.2 Description of test . 13
7.5.3 Test equipment — Apparatus . 13
7.5.4 Test process scope.14
7.5.5 Test equipment — Procedure .14
7.6 Method C – Test procedure as per AMPP TM21442-2023 . 15
7.6.1 Description of Test . 15
7.6.2 Test Equipment – Apparatus . .16
8 Test report . 17
Annex A (informative) Corrosion testing of conditioned and heat conditioned test samples . 19

iii
ISO/DIS 19277-1:2026(en)
Annex B (informative) Example of test report for CUI coating acceptance.20
Annex C (informative) Example of test report for vertical pipe test .24
Annex D (informative) Optional Cryogenic Cycling Testing .29
Bibliography .32

iv
ISO/DIS 19277-1:2026(en)
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.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO [had/had not] received notice of
(a) patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 67, Oil and gas industries including lower carbon
energy.
This second edition cancels and replaces the first edition (ISO 19277:2018), which has been technically
revised. The main changes are as follows:
— Document has now been split into two parts; this document is Part 1 dealing with liquid applied coatings
only, and Part 2 is dealing with tape and sheet applied products.
— Cryogenic cyclic test has now been moved from the standard text and is included in the Annex D
(Informative).
— An additional CUI simulation test has been added and option included to perform one of the three listed
test methods
— Tests on stainless steel specimens have been deleted. Qualification testing of coating system shall be
carried out on carbon steel. The system is then also qualified for use on stainless steel.
A list of all parts in the ISO 19277 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

v
ISO/DIS 19277-1:2026(en)
Introduction
Unprotected carbon steel in insulated service with the presence of water and concentrating contaminants
from the atmosphere or surrounding sources can cause accelerated corrosion and lead to severe metal
loss. Additionally, unprotected austenitic and duplex stainless steels can suffer external chloride-induced
stress corrosion cracking if contaminates, such as chlorides from the atmosphere and or the insulation, are
present at the steel surface. Therefore, steel structures under insulation are normally protected to prevent
corrosion-related damage during the operational life required of the equipment.
There are different ways of protecting steel structures from corrosion under insulation. This document deals
with protection by use of coating when used as part of a system, including insulation and cladding materials,
which can work together to prevent corrosion under insulation (CUI). All components of the corrosion
prevention system are important in achieving adequate corrosion protection. This document only deals
with the coating part of the corrosion protection system with focus on typical CUI coating environments.
Further, this document focuses on accelerated testing protocols and acceptance criteria, so that interested
parties can make informed decisions.
To ensure effective corrosion protection of steel structures and equipment, it is necessary for owners of
such structures, planners, consultants, companies carrying out corrosion protection work, inspectors
of protective coatings and manufacturers of coating materials to have at their disposal state-of-the-art
information in a concise form on corrosion protection by coating systems. Such information has to be as
complete as possible, unambiguous and easily understandable to avoid difficulties and misunderstandings
between the interested parties with the practical implementation of protection work.
This document is intended to give the abovementioned information to people who have some technical
knowledge of coatings and the process operations of the equipment. It is assumed that the user of this
document is familiar with other relevant International Standards, particularly those dealing with surface
preparation, inspection/testing of coatings, and relevant regulations.
Future parts of this document are to be developed which are to include other subjects like higher
temperature, cyclic and intermittent service, testing of coatings for maintenance and repair, tape-applied
coating materials, etc.
vi
DRAFT International Standard ISO/DIS 19277-1:2026(en)
Oil and gas industries including lower carbon energ —
Qualification testing and acceptance criteria for protective
coating systems under insulation —
Part 1:
Liquid applied coatings
1 Scope
This document describes various corrosion under insulation (CUI) environments in refineries and other
related industries and environments and establishes CUI environmental categories including operating
temperature ranges from −45 °C to 204 °C for topside and aboveground service only. This document specifies
both established and other test methods for the assessment of coatings used for prevention of CUI for each
given environment. This document also provides acceptance criteria for each CUI environment.
NOTE The test results and acceptance criteria can be considered an aid in the selection of suitable coating
systems. For service or peak temperatures over 204 °C testing acceptance criteria can be agreed between interested
parties. Additional or other test and acceptance measures are possible but require particular agreement between the
interested parties.
This document covers spray-applied coatings applied on new carbon steel for use in CUI service. The coatings
can be used for new built structures and for existing structures where maintenance of the coating is needed.
This document does not cover testing of sacrificial coatings, such as inorganic zinc, as these coatings can be
consumed quickly in wet environments. Developing accelerated corrosion testing for what can be continuous
wet service with sacrificial coatings is beyond the scope of this document.
“Non-through porosity” thermal spray aluminium coatings with greater than 250 µm dry film thickness
can be tested and qualified in accordance with this document. This document does not cover tape and sheet
applied products for use in preventing CUI.
This document does not deal with other aspects of coating degradation, such as those caused by abrasion,
erosion, ultraviolet degradation or other methods that can exist given specific environment and construction
methods.
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.
ISO 554, Standard atmospheres for conditioning and/or testing — Specifications
ISO 1513, Paints and varnishes — Examination and preparation of test samples
ISO 2409, Paints and varnishes — Cross-cut test
ISO 2812-2, Paints and varnishes — Determination of resistance to liquids — Part 2: Water immersion method
ISO 4624, Paints and varnishes — Pull-off test for adhesion
ISO 4628-2, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of
defects, and of intensity of uniform changes in appearance — Part 2: Assessment of degree of blistering

ISO/DIS 19277-1:2026(en)
ISO 4628-3, Paints and varnishes — Evaluation of quantity and size of defects, and of intensity of uniform
changes in appearance — Part 3: Assessment of degree of rusting
ISO 4628-4, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of
defects, and of intensity of uniform changes in appearance — Part 4: Assessment of degree of cracking
ISO 4628-5, Paints and varnishes — Evaluation of quantity and size of defects, and of intensity of uniform
changes in appearance — Part 5: Assessment of degree of flaking
ISO 4628-8, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of
defects, and of intensity of uniform changes in appearance — Part 8: Assessment of degree of delamination and
corrosion around a scribe or other artificial defect
ISO 7384, Corrosion tests in artificial atmosphere — General requirements
ISO 9227, Corrosion tests in artificial atmospheres — Salt spray tests
ISO 12944-6, Paints and varnishes — Corrosion protection of steel structures by protective paint systems —
Part 6: Laboratory performance test methods
ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling
ISO 19840, Paints and varnishes — Corrosion protection of steel structures by protective paint systems —
Measurement of, and acceptance criteria for, the thickness of dry films on rough surfaces
AMPP TM 21442-2023, Test method for evaluation of protective coatings for use under insulation.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological 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/
3.1
artificial ageing
procedure designed to accelerate the ageing of a coating system, i.e. to reduce the corrosion-protective
efficiency more rapidly than by natural weathering
[SOURCE: ISO 12944-6:2018, 3.1, modified — ‘paint system’ has been changed to ‘coating system’.]
3.2
corrosion under insulation
CUI
corrosion that is a result of the effect of moisture and contaminants, on the steel surfaces under thermal
insulation
3.3
dry film thickness
DFT
thickness of a coating remaining over the peaks of a rough surface when the coating has hardened
3.4
durability
expected life of a protective coating system to the first major maintenance coating
[SOURCE: ISO 12944-8:2017, 3.3, modified — ‘paint system’ has been changed to ‘coating system’ and
‘maintenance painting’ has been changed to ‘maintenance coating’.]

ISO/DIS 19277-1:2026(en)
3.5
nominal dry film thickness
NDFT
dry film thickness specified for each coat or for the whole coating system
3.6
peak temperature
maximum temperature for the designed system, including possible upsets and temperature reached as a
result of maintenance efforts such as steam cleaning
3.7
sacrificial coating
coating that provides corrosion protection by sacrificing or being consumed in the act of protecting the
substrate
4 Performance testing design
4.1 Relationship between artificial testing and natural exposure
The selection of a coating system for specific conditions should preferably be based on experience from the
use of the system in similar cases. The reason is that the durability of a CUI coating system depends on many
external factors, such as the environment, the design of the structure, the insulation material, the weather
proofing (cladding), the surface preparation, the application, drying procedures, service temperature,
thermal shock, thermal cycling, peak temperature, amount of moisture, contaminants and other variables.
The durability is also linked to the chemical and physical characteristics of the system, e.g. the type of
binder, the dry film thickness. These CUI related performance characteristics can be evaluated by artificial
tests. Resistance to water or moisture, boiling water, steam interface, electrolytes in the system, thermal
exposure, thermal shock, and thermal cycling are of primary interest.
Artificial tests and durations specified in this document have been selected to help ensure that potential
coating systems will have the characteristics needed for the durability required in the intended service.
Results from artificial tests should be used with caution, because artificial testing will not necessarily have
the same effect as natural exposure. Many factors have an influence on the progress of degradation and,
in the laboratory, it is not possible to accelerate all of them using the most effective method. It is therefore
difficult to make a reliable ranking of coating systems of very different compositions from artificial tests in
the laboratory. This can sometimes lead to efficient protective coating systems being rejected because they
cannot pass these tests.
4.2 Laboratory tests
As CUI environments are very specific and have special requirements, several tests are included so that
coating products can exhibit performance in harsh environments typical of CUI exposure. These include
thermal performance, boiling water, thermal shock, thermal cycling, peak temperature performance, and
long term isothermal conditions. In addition, these coating products shall provide corrosion protection
for long periods of time at ambient conditions, and in possibly wet conditions related to initial coating
application prior to process start up, time associated with process shutdowns, and short term mothballing
of the facility.
Standard weathering testing procedures shall be used to establish ambient related corrosion control test
procedures and acceptance criteria. Both air dried and conditioned test samples and heat conditions test
samples shall be evaluated.
Additional CUI and high temperature related tests shall also be used in order to verify the ability of a coating
to work under insulation at the prescribed conditions.
Inorganic zinc primers or other sacrificial coatings are no longer recommended in CUI environments due
to the accelerated corrosion related to wet environments. If testing and acceptance is required, additional
testing, as agreed between the interested parties, can be performed. However, long term wet environments

ISO/DIS 19277-1:2026(en)
are difficult to accelerate and as such the specifier/owner should be careful with any acceptance criteria for
sacrificial coatings.
4.3 Additional laboratory tests
Other test methods may also be used by agreement between interested parties.
5 CUI classification environments
Table 1 provides a list of CUI classification environments including the minimum and maximum temperatures
for all environments. These descriptions include both isothermal and cyclic conditions.
Table 1 — CUI classification environments
Classification Minimum temperature Peak temperature
CUI-1 −45 °C to 60 °C
CUI-2 −45 °C 60 °C to 150 °C
CUI-3 −45 °C 150 °C to 204 °C
Further, each coating should be qualified for each specific CUI classification where it is intended to be used. A
coating that meets the requirements of a CUI-1 classification does not necessarily meet the requirements of a
CUI-3 classification, and a coating that meets the requirements of a CUI-3 classification does not necessarily
meet the requirements of a CUI-1 classification. By consolidating testing some tests can be used for more
than one classification.
For insulated service for temperatures above 204 °C, additional testing may be performed as agreed by
interested parties.
6 Test specimens
6.1 Test specimens’ requirement
This document requires the use of test specimens and other testing surfaces that are available as standard
shapes typically available on the marketplace. Both A-36 or S275 carbon steel test specimens shall be
incorporated in testing and also shapes as described in 6.2.1 to 6.2.4.
6.2 Steel substrates
Test specimens will be as follows unless otherwise agreed to and documented.
6.2.1 Artificial Ageing and Thermal Cycling tests
Carbon steel test panels shall be made of A-36 or S275 carbon steel. The minimum panel size shall be
3 mm × 150 mm × 70 mm or as agreed and documented by the parties. The thickness of the test panels shall
not allow for bending as a result of heating and quenching. Unless otherwise agreed, the panel surface shall
be prepared by abrasive blast-cleaning to meet the requirements of the corresponding technical product
data sheet as per the coating manufacturer’s instructions. In all other respects, test panels shall comply with
ISO 7384.
6.2.2 Method A- Multi-Phase CUI cyclic corrosion test
Square carbon steel tubing (A-36, ASTM A-500, or S275) ASIC standard shape HSS4X4X1/4 measuring
approximately 101,4 mm by 101,4 mm, 406,3 mm long with a wall thickness of 6,35 mm shall be used for
the multi-phase CUI cyclic test. Each coating sample area shall be a minimum of 101,4 mm long, on all four
sides of the square tube with just the front face scribed with an X-cut. Each tube shall have an endcap welded
on each end with a 25,4 mm pipe 101,5 mm long with a threaded connector. The two pipes shall be centred

ISO/DIS 19277-1:2026(en)
horizontally and shall be vertically attached with a centre 25,4 mm down from the top of the square tube. The
completed tube should be tested to ensure that the welds do not leak. Figure 2 provides a general layout (see
7.4.2). Unless otherwise agreed, the tube’s exterior surfaces shall be prepared by abrasive blast-cleaning to
meet the requirements of the corresponding technical product data sheet as per the coating manufacturer’s
instructions.
6.2.3 Method B - Vertical Pipe Test
A standard black carbon steel pipe (A-36 or S275), approximately 600 500 mm long, with 50 mm outside
diameter with typical wall thickness of 45 mm shall be used for the vertical insulation pipe test. Unless
otherwise agreed, the test surface shall be prepared by abrasive blast-cleaning to surface preparation to
meet the requirements of the corresponding technical product data sheet as per the coating manufacturer’s
instructions.
6.2.4 Method C – Test procedure as per AMPP TM21442-2023
The pipe spools shall be made of commercial grade low carbon steel (A-36 or S275). Multiple test specimens
of each system being tested should be prepared. A minimum of two (2) test specimens is recommended.
However, the use of single specimens would be valid if accepted by the end-user. The length of each pipe
spool shall be between 15 cm (6 in) and 30 cm (12 in). Unless otherwise agreed, the test surface shall be
prepared by abrasive blast-cleaning to surface preparation to meet the requirements of the corresponding
technical product data sheet as per the coating manufacturer’s instructions.
6.3 Sampling of coatings
A representative sample of the product to be tested (or of each product in the case of a multi-coat system)
shall be taken in accordance with ISO 15528. Each sample for testing shall be examined and prepared in
accordance with ISO 1513.
6.4 Number of test specimens
At least three specimens shall be prepared for each test, unless otherwise specified. Testing should be done
in triplicate.
6.5 Coating systems
6.5.1 Coating application
The test specimens/surfaces shall be dry and free of dust, grease and any other foreign matter, immediately
prior to coating application and in keeping with the coating manufacturer’s recommendations. The test
specimens/surfaces shall be coated (preferably by spraying), air dried and cured in strict accordance with the
coating manufacturer's recommendations. Each coat shall be homogenous in thickness and appearance and
free from runs, sags, misses, pinholes, wrinkling, gloss variation, cissing, particle inclusions, dry overspray
and blistering. If the manufacturer's drying requirements are in conflict with 6.5.4, the requirements of
6.5.4 shall take precedence, unless agreed to by all parties. Appropriate protection shall be applied to the
edges and back side of test specimens.
6.5.2 Dry film thickness
The method and procedure for checking dry film thickness shall be in accordance with ISO 19840 for rough
surfaces. After each coat is sufficiently hardened, the dry film thickness of the applied coating shall be
measured on the test surface of the test specimen/surface at five locations (in the centre and each corner, at
least 15 mm to 20 mm from the panel edge or rounded surface of the square tube) and these measurements
shall be recorded as the minimum, arithmetic mean and maximum. Dry film thickness values for each coat
shall be in accordance with ISO 19840 for both individual readings and average DFT. Maximum DFT shall
never exceed 1,25 x NDFT, both for each coat and with respect to total DFT. If NDFT of any coat is ≤60 µm,
max DFT shall never exceed 1,5 x NDFT.

ISO/DIS 19277-1:2026(en)
6.5.3 Overcoating interval
For each layer of coating application, the overcoating interval shall comply with the coating manufacturer's
recommendations.
6.5.4 Conditioning
Unless otherwise agreed, the coated test samples shall be conditioned for three weeks in a standard
atmosphere of 23 °C ± 2 °C with 50 % ± 5 % relative humidity, before testing, and in accordance with
the requirements of the corresponding technical product data sheet as per the coating manufacturer’s
recommendations.
6.5.5 Heat conditioning
Heat conditioning of the test samples shall be performed on applied and conditioned test samples. Heat
conditioning shall consist of heating the conditioned test specimens to the maximum temperature of the
classification for 20 h in a muffler oven or other similar device. The test specimens shall then be removed
and air cooled for 4 h. This process shall be repeated a total of 5 times, providing for a total of 100 h exposure
at maximum temperature of the classification and 20 h of air-cooling time.
6.6 Scribe
If a scribe is required for testing of coatings on steel substrates, the scribe shall be in accordance with
ISO 12944-6. Special care should be taken to ensure that potentially hot and small metal fragments do not
affect the sample. Individual test procedures will indicate the need of a scribe for testing.
For the multi-phase CUI Simulation test as described in section 7.4 alternative guidelines for the required scribe
should be used.
6.7 Reference system
It is recommended to use a coating system that has been in successful use for years on site and whose
performance as indicated by laboratory testing is well known, as a reference system. This system shall be
as similar as possible in composition and/or generic type and dry film thickness to the coating system being
tested.
7 Test procedures and assessment
7.1 Assessment and acceptance
All tests shall be conducted in triplicate. At least two of the three tests shall comply with the requirements
specified in this document. For CUI simulation testing only one of the three documented test methods
shall be carried out and included in the test report. CUI simulation test method choice should be agreed
between parties. Triplicate for the multiphase CUI cycle test shall be three separate tubes run in three
separate test cycles. Triplicate for the vertical pipe test shall be three separate tubes. Triplicate for the AMPP
21422 CUI test shall be three separate tubes.
7.2 Assessment of adhesion and artificial ageing
7.2.1 Adhesion testing before artificial ageing
The applied and conditioned coating sample specimens and the heat conditioned coating sample specimens
shall be tested for adhesion. This includes the carbon steel test specimens. Table 3 provides list of testing
and acceptance criteria.
ISO/DIS 19277-1:2026(en)
Table 3 — Adhesion assessment before artificial ageing for carbon steel test specimens
Assessment Requirement Conditions
method
ISO 2409 Classification <2 If the dry film thickness of the coating system is
less than or equal to 250 µm.
ISO 4624 If the dry film thickness of the coating system is
greater than 250 µm.
Pull-off breaks shall consist of 0 % adhesive fail-
ure between the steel and the primer (first coat)
i.e. A/B fractures, unless values are ≥ 5 Mpa.
7.2.2 Artificial ageing
Table 4 provides test methods and durations as required for each classification. Table 5 provides acceptance
criteria for these tests. Annex A provides a rationale for the testing of ambient and heat conditioned test
specimens.
Table 4 — Ambient test methods and duration for carbon steel test specimens
ISO 9227 ISO 2812-2
(neutral salt spray) (water immersion)
Duration Duration
Classification
Scribed Scribed
Applied and Applied and
Heat conditioned Heat conditioned
conditioned conditioned
CUI-1 720 hours 480 hours 3 000 hours 2 000 hours
CUI-2 720 hours 480 hours 3 000 hours 2 000 hours
CUI-3 720 hours 480 hours 3 000 hours 2 000 hours
Table 5 — Ambient corrosion test acceptance criteria
Test method Classifications ISO 4628-2 ISO 4628-3 ISO 4628-4 ISO 4628-5 ISO 12944-
6 Annex A.2
ISO 9227 CUI-1 CUI-2 CUI-3 0 (S0) Ri 0 0 (S0) 0 (S0) 1,5 mm
ISO 2812-2 CUI-1 CUI-2 CUI-3 0 (S0) Ri 0 0 (S0) 0 (S0) 6,0 mm
Time of assessment (after end of test) Immediately <8 h
7.2.3 Adhesion testing after artificial ageing
The artificially aged test specimens shall be tested for adhesion after the prescribed duration (time of
assessment) in the standard atmosphere in accordance with ISO 554. This includes only the carbon steel test
specimens. Table 6 provides a list of testing and acceptance criteria.

ISO/DIS 19277-1:2026(en)
Table 6 — Adhesion assessment after ambient corrosion testing for carbon steel test specimens
Assessment Requirements Time of assessment Conditions/Remarks
method
ISO 2409 Classification <2 Assessment after a If the dry film thickness of the
minimum of 7 days and coating system is less than or
maximum of 14 days equal to 250 µm.
reconditioning, in
standard conditions as
defined in ISO 3270
ISO 4624 Assessment after a If the dry film thickness of the
minimum of 7 days and coating system is greater than
Pull-off breaks shall consist of
maximum of 14 days 250 µm.
0 % adhesive failure between
reconditioning, in
the steel and the primer (first
standard conditions as
coat) i.e. A/B fractures, unless
defined in ISO 3270
values are ≥ 5 Mpa
7.3 Thermal cycling test
The test specimens are placed in the oven and heated. When the test specimen reaches the maximum
temperature of the classification, it shall immediately be dipped/quenched into ice water covering at least
3/4 of the test specimen and left immersed until the temperature of the test sample metal temperature is
reduced to <15 °C. This shall be repeated for the number of cycles required. The coated surface shall then be
evaluated. Minimum and maximum thermal cycling temperatures and the number of cycles are provided for
each CUI classification in Table 7. Acceptance criteria are provided in Table 8.
Table 7 — Thermal cycling test for carbons steel test specimens
Classification Minimum temperature Maximum temperature Cycles
CUI-1 5 °C 60 °C 20
CUI-2 5 °C 150 °C 20
CUI-3 5 °C 204 °C 20
Table 8 — Thermal cycling acceptance criteria
Classifications ISO 4628-2 ISO 4628-3 ISO 4628-4 ISO 4628-5
CUI-1 0 (S0) Ri 0 0 (S0) 0 (S0)
CUI-2 0 (S0) Ri 0 0 (S0) 0 (S0)
CUI-3 0 (S0) Ri 0 0 (S0) 0 (S0)
7.4 Method A - Multi-phase CUI cyclic corrosion test
7.4.1 Description of test
The multi-phase CUI cyclic corrosion test process is used to test the ability of the coating to work in typical
environments where CUI occurs. This test process includes dry heat, thermal shock, immersion, boiling
water, steam interface, and shut down time. This test takes six weeks and does not consider the effect related
to individual insulation materials. This test process is used for CUI-2 and CUI 3, as these CUI coatings extend
into the boiling water range.
7.4.2 Test equipment-apparatus
The multi-phase cyclic CUI test method is designed to provide an overall test procedure for coatings for
elevated temperature insulated service. It includes cyclic testing methods providing dry heat, intermittent
boiling water for an extended period of time, a steam interface, and an ambient state where there is no
heating.
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