ISO 5622:2026

• Abstract:

  This document specifies a method for the determination of carbon monoxide (CO) in the vapour phase of tobacco heating system according to ISO 5501-1, by a non-dispersive infrared analyser (NDIR). NOTE If tested products provide CO levels outside of the upper limit of the calibration range described in this document, then the calibration range described in ISO 22947 applies.

• Status: Published
• Publication Date: 09-Jun-2026
• ICS: 65.160 - Tobacco, tobacco products and related equipment
• Technical Committee: ISO/TC 126 - Tobacco and tobacco products
• Drafting Committee: ISO/TC 126 - Tobacco and tobacco products
• Current Stage: 6060 - International Standard published
• Start Date: 10-Jun-2026
• Due Date: 03-Oct-2026
• Completion Date: 10-Jun-2026

ISO 5622:2026 is an ISO International Standard for electrically heated tobacco products (eHTPs). It specifies how to determine carbon monoxide (CO) in the vapour phase of tobacco heating system aerosol using a non-dispersive infrared analyser (NDIR), with the puffing regime taken from ISO 5501-1. It is written for laboratories and product teams that need a repeatable way to measure and report CO from eHTPs.

What does ISO 5622:2026 specify?

ISO 5622:2026 specifies a laboratory method for measuring CO in the vapour phase of aerosol from an eHTP by NDIR. The document is organized into clauses covering scope, references, terms, principle, apparatus, reagents, procedure, calculation of results, repeatability and reproducibility, and test reporting.

The method is built around aerosol generation and collection according to ISO 5501-1. A note in the scope links the method to ISO 22947 when a product produces CO above the upper calibration limit used here.

What are the key requirements of ISO 5622:2026?

Sampling, conditioning and aerosol generation

ISO 5622:2026 requires the HTP sample to be conditioned in sealed packs under the ISO 5501-1 conditions before testing. The puffing machine must then aerosolize the product in accordance with ISO 5501-1 and any relevant manufacturer instructions.

In practice, this means the sample preparation step is part of the measurement result. If conditioning or puffing differs, the CO result is not directly comparable.

Collection and measurement setup

ISO 5622:2026 requires collection of the total vapour phase without interfering with normal puffing-machine performance. The collection container must be checked for impermeability, and the gas bag volume must suit the actual aerosolization conditions and include the vapour phase plus clearing puffs.

The analyser must be an NDIR instrument suitable for the expected concentration range, with specified performance for linearity, resolution, repeatability, and limited response to carbon dioxide and water vapour. This matters because the method measures a low-emission gas signal and the instrument must not misread other gases as CO.

Calibration and verification

ISO 5622:2026 requires calibration with CO standard gases in nitrogen, with at least two mixtures covering the working range. The analyser is zeroed with air, adjusted with a standard gas, checked against a second gas, and the calibration relationship is established at least weekly.

Before measurement each day, the calibration is checked again. If the observed value differs from the expected value beyond the stated limit, the full calibration is repeated. In practice, this makes day-to-day drift visible before it affects results.

Test run and clearing puffs

ISO 5622:2026 requires aerosolization of the consumables, with one clearing puff between consumables and five clearing puffs at the end of the collection after the final consumable is removed. The total number of puffs on each port is recorded, and the collected vapour phase is then measured for CO.

This detail matters because the reported result depends on the full puff count, not just the product puffs.

Calculation and reporting

ISO 5622:2026 gives formulas for average CO volume per consumable and average CO mass per HTP. The calculation uses the observed CO concentration, puff volume, pressure, temperature, number of puffs, and number of consumables, then converts the result to mass using gas properties.

The test report must identify the samples, sampling details, test conditions, method used, results, and any relevant operating conditions. It also records the analyser type, puffing machine, environmental conditions, and the CO result per consumable or per puff as needed.

What terms does ISO 5622:2026 define?

• Tobacco heating system (THS) - a heated tobacco product (HTP) used together with a tobacco heating device (THD) to produce aerosol.
• Electrically heated tobacco product (eHTP) - the HTP type covered by this standard, heated by an electrical device.
• Tobacco heating device (THD) - the device that heats the HTP; the standard notes that a THD may be reused for multiple HTP samples.
• Vapour phase - the part of the aerosol that passes the particulate phase trap during collection according to ISO 5501-1.
• Clearing puff - a puff taken immediately after the THS is removed from the machine holder.
• Non-dispersive infrared analyser (NDIR) - the instrument used to measure CO in the collected vapour phase.

Who uses ISO 5622:2026?

ISO 5622:2026 is used by test laboratories, eHTP manufacturers, and quality or regulatory teams that need CO data from machine-based aerosol measurements. It is also relevant to buyers and auditors who need to understand how a reported CO value was generated and what conditions were used.

The standard is especially useful when comparing products, checking emissions during development, or documenting test results for technical files and reports. It supports controlled laboratory measurement, not human exposure assessment.

Which standards are used with ISO 5622:2026?

• ISO 5501-1 - provides the standard conditions for aerosol generation and collection for electrically heated tobacco products.
• ISO 6080 - provides the vocabulary used for tobacco heating systems and related terms.
• ISO 22947 - is the calibration-range reference used when CO levels exceed the upper limit covered here.
• ISO 5725-2 - is used in the precision study cited for repeatability and reproducibility analysis.

What does the ISO 5622:2026 document contain?

ISO 5622:2026 contains the test principle, apparatus requirements, reagents, a step-by-step procedure, calculation formulas, and guidance for reporting results. It also includes performance checks for the collection container and analyser, such as impermeability, linearity, and response to carbon dioxide and water vapour.

The document further provides repeatability and reproducibility information based on a proficiency study using eHTPs and NDIR analysis. The reporting section lists the product identification, sampling details, test conditions, and result fields needed for a complete laboratory record.

International
Standard
ISO 5622
First edition
Tobacco and tobacco products —
2026-06
Electrically heated tobacco products
(eHTPs) — Determination of carbon
monoxide in the vapour phase of
tobacco heating system aerosol by
NDIR method with a puffing regime
according to ISO 5501-1
Reference number
© 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
6 Reagents . 3
7 Procedure . 3
7.1 Conditioning.3
7.2 NDIR analyser calibration .3
7.3 Aerosolization and collection of the vapour phase .3
8 Expression of results . 4
8.1 Calculation of the average volume of carbon monoxide per consumable of tobacco
heating system .4
8.2 Calculation of the average mass of carbon monoxide per HTP .4
9 Repeatability and reproducibility . 5
10 Test report . 5
10.1 General .5
10.2 Product information about the samples and samples identification .5
10.3 Sampling .6
10.4 Description of test .6
10.5 Test results .6
Bibliography . 7

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 126, Tobacco and tobacco products.
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.

iv
Introduction
Tobacco heating systems (THS) are designed to heat a tobacco substrate, to produce a nicotine-containing
aerosol. A THS is a combination of a heated tobacco product (HTP) and a tobacco heating device (THD).
The HTP part of the THS is a product containing a tobacco substrate that is designed to be heated. This
combination significantly reduces toxicants, such as carbon monoxide.
With the emerging development and commercialisation of HTPs, there are a number of different approaches
to heating the HTP, categorised as electrically, aerosol and carbon, HTPs (eHTP, aHTP and cHTP), respectively
as described in ISO 6080.
Specific parameters and standard conditions for aerosol generation and collection from electrically heated
tobacco products have been described in ISO 5501-1.
Additionally, the expected level of carbon monoxide emissions from eHTPs is significantly lower than those
[1]
from cigarettes, necessitating a lower calibration range than that described in ISO 22947 .
[2]
The method in this document is based upon CORESTA recommended method CRM 108 which was written
on the basis of the results obtained in an interlaboratory study conducted in 2021 involving seventeen
laboratories and four THS samples. The results of this interlaboratory study were published by CORESTA in
[3]
a technical report HTP-280-CTR . The results showed repeatability and reproducibility values for aerosol
heated tobacco products (aHTPs) were not statistically relevant. Carbon heated tobacco products (cHTPs)
has not been commercially available.
This document defines and specifies the requirements for an electrically heated tobacco product (eHTP) for
the quantification of carbon monoxide in the vapour phase of the aerosol.
No machine puffing regime can represent all human puffing behaviour.
— It is recommended that eHTP also be tested under conditions of a different intensity of machine puffing
than those specified in this document.
— Machine puffing testing is useful to characterize eHTP emissions for design and regulatory purposes, but
communication of machine measurements to users can result in misunderstandings about differences in
exposure and risk across brands.
— Aerosol emission data from machine measurements may be used as inputs for product hazard
assessment, but they are not intended to be nor are they valid as measures of human exposure or risks.
Communicating differences between products in machine measurements as differences in exposure or
risk is a misuse of testing using ISO standards
IMPORTANT — This document is a reference document for ISO standards and measurement on tobacco
heating systems (e.g. ISO 6080). Regulation and standardisation are independent from each other, and
standardisation does not pre-empt regulation.

v
International Standard ISO 5622:2026(en)
Tobacco and tobacco products — Electrically heated tobacco
products (eHTPs) — Determination of carbon monoxide in
the vapour phase of tobacco heating system aerosol by NDIR
method with a puffing regime according to ISO 5501-1
WARNING — The use of this document can involve hazardous materials, operations and equipment.
This document does not purport to address all the safety problems associated with its use. It is the
responsibility of the user of this document to establish appropriate safety and health practices and
determine the applicability of any other restrictions prior to use.
1 Scope
This document specifies a method for the determination of carbon monoxide (CO) in the vapour phase of
tobacco heating system according to ISO 5501-1, by a non-dispersive infrared analyser (NDIR).
NOTE If tested products provide CO levels outside of the upper limit of the calibration range described in this
[1]
document, then the calibration range described in ISO 22947 applies.
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 5501-1, Tobacco heating systems — Definitions and standard conditions for aerosol generation and
collection — Part 1: Electrically heated tobacco products (eHTPs)
ISO 6080, Toba
...