prEN ISO 9360-2

• Status: Not Published
• Publication Date: 07-Feb-2028
• ICS: 11.040.10 - Anaesthetic, respiratory and reanimation equipment
• Technical Committee: CEN/TC 215 - Respiratory and anaesthetic equipment
• Drafting Committee: CEN/TC 215 - Respiratory and anaesthetic equipment
• Current Stage: 4020 - Submission to enquiry - Enquiry
• Start Date: 20-Aug-2026
• Completion Date: 20-Aug-2026
• Ref Project: oSIST prEN ISO 9360-2:2026 - Heat and moisture exchangers, and breathing system filters for respired gases - Part 2: Measurement of moisture loss (ISO/DIS 9360-2:2026)

• Referred By: EN ISO 12855:2022 - Electronic fee collection - Information exchange between service provision and toll charging (ISO 12855:2022)
• Effective Date: 28-Jan-2026
• Referred By: EN ISO 12855:2025 - Electronic fee collection - Information exchange between service provision and toll charging (ISO 12855:2025)
• Effective Date: 28-Jan-2026
• Revises: EN ISO 9360-2:2009 - Anaesthetic and respiratory equipment - Heat and moisture exchangers (HMEs) for humidifying respired gases in humans - Part 2: HMEs for use with tracheostomized patients having minimum tidal volumes of 250 ml (ISO 9360-2:2001)
• Effective Date: 19-Feb-2025

prEN ISO 9360-2 is a draft standard for measuring moisture loss from heat and moisture exchangers (HMEs), HMEFs and breathing system filters (BSF) used with respired gases. It specifies a test apparatus and two test methods so manufacturers, laboratories and buyers can compare moisture-conserving performance under defined conditions.

What does prEN ISO 9360-2 specify?

prEN ISO 9360-2 specifies how to measure moisture loss from HMEs, including devices incorporating breathing system filters, and from HMEs used with tracheostomized patients without a machine port. It focuses on comparative laboratory measurement, not on clinical performance in use.

The document is organized into:

• Clause 1 - Scope
• Clause 2 - Normative references
• Clause 3 - Terms and definitions
• Clause 4 - Measurement of moisture loss
• Clause 5 - Measurement of moisture loss from HME/HMEFs without a machine port
• Annex A - Parts and specifications for the figures
• Annex B - Rationale
• Bibliography

Annex	What it covers
Annex A	Lists the parts and specifications used in Figures 1 and 2
Annex B	Gives the rationale for the main test provisions

What are the key requirements of prEN ISO 9360-2?

The core requirement in prEN ISO 9360-2 is to determine device performance from the mass of water lost by a humidity generator during a defined test. That means the test result is a moisture-loss measurement, not a direct clinical humidification measurement.

Test principle and what is measured

Clause 4.1 says the device is assessed by recording the water mass lost from the specified test apparatus. Annex B explains why this matters: the apparatus is intended to simulate use and give comparative data between devices.

In practice, the user needs a stable, repeatable setup and a balance of suitable accuracy. The moisture retained by the device is treated as moisture lost from the apparatus, so weighing must be done carefully and consistently.

Test apparatus

Clause 4.2 defines the apparatus as a bidirectional flow system with a humidity generator, an air delivery system, weighing equipment, flowrate measuring equipment and a calibration HME. The calibration HME is used to confirm that the rig behaves as intended.

This matters because the test depends on the apparatus itself being reproducible. Annex A gives the key parts and their features, while the figures show how the parts are arranged.

Test conditions for devices with a machine port

Clause 4.3 requires testing at the conditions in Table 1 that fall within the manufacturer’s stated operating range. The device is also tested at the maximum tidal volume recommended by the manufacturer when that value is above the upper range in the table.

In practice, this means the test lab does not choose a single convenient setting. It has to cover the relevant operating range so the results reflect how the device is intended to be used.

Procedure and calculation

Clause 4.4 sets out the sequence: condition the apparatus, run the test with the device in place, record the humidity-generator mass at the start and after defined periods, and calculate moisture loss for the first hour and for the full recommended use period.

For the reader, the important point is that the result is normalized to air volume leaving the machine port. That makes the moisture-loss figure usable for comparing devices tested under the same conditions.

Calibration check

Clause 4.4 also requires confirmation of the apparatus using the calibration HME. The measured moisture loss must fall within the specified ranges in Table 2.

This is a practical quality check on the rig, not just on the device. If the calibration HME does not behave as expected, the test setup is not ready for valid measurements.

Devices without a machine port and supplemental oxygen use

Clause 5 covers HMEs and HMEFs without a machine port, including use with tracheostomized patients. The test chamber replaces the machine-port configuration, but the same basic measurement approach is used.

Clause 5 also requires repeat testing for devices intended to provide supplemental oxygen, using the maximum oxygen flowrate recommended by the manufacturer or the stated fallback value in the document. In practice, this means oxygen use has to be part of the performance assessment when the device is designed for that application.

What terms does prEN ISO 9360-2 define?

• Heat and moisture exchanger (HME) - A device used to raise the water content and temperature of respired gas before it reaches the patient.
• Heat and moisture exchanger with filter (HMEF) - An HME that also incorporates breathing system filter function.
• Breathing system filter (BSF) - A filter used in a breathing system; the document includes BSF because these devices also affect moisture delivered to inspired gases.
• Humidity generator (HG) - The part of the test apparatus that produces humidified air and whose mass loss is measured.
• Machine port - The connection point used in the device test arrangement for gas delivery from the apparatus.
• Tidal volume - The breath volume setting used to define the test condition and the intended patient use range.

Who uses prEN ISO 9360-2?

prEN ISO 9360-2 is used by manufacturers of HMEs, HMEFs and BSF, by test laboratories, and by quality and regulatory teams responsible for product verification. It is also relevant to buyers and technical evaluators in anaesthetic and respiratory equipment.

In practice, these users rely on the document to:

• set up a repeatable moisture-loss test
• verify a device design against stated operating conditions
• check the test rig with a calibration HME
• compare products on a common laboratory basis
• document results for product development, quality control and conformity work

What changed in prEN ISO 9360-2 from the previous edition?

prEN ISO 9360-2 is part of the revision that combines requirements previously found in ISO 9360-1:2000 and ISO 9360-2:2001 for this topic. The stated change is corrected dimensions for the calibration HME and the heated water bath side view.

Which standards are used with prEN ISO 9360-2?

• ISO 5356-1:2015 - Provides the conical connector dimensions used in the test chamber and air-delivery connections.
• ISO 9360-1:202X - Supplies the common requirements for the series and the terms and definitions used here.
• ISO TS 24172 - Gives an alternative test method for heat and moisture exchangers.
• ISO 80601-2-74:2026 - Covers active HMEs, which are referenced as a separate topic.

The document also sits within the ISO 9360 series:

• Part 1 - Common requirements
• Part 2 - Measurement of moisture loss
• Part 3 - Measurement of filtration performance

What does the prEN ISO 9360-2 document contain?

The document contains two test methods, one for devices with a machine port and one for HME/HMEFs without a machine port. It provides the test principle, apparatus, test conditions, procedure and calculation method for moisture loss.

It also includes figures for the apparatus and the calibration HME, a table of test conditions, and a table of acceptable moisture-loss ranges for the calibration check. Annex A lists the parts used in Figures 1 and 2, and Annex B explains the rationale behind the selected flow pattern, apparatus design and test conditions.

For a laboratory, this means the document is practical as a setup and verification guide for moisture-loss testing. For a product team, it shows what to measure, how to run the comparison test, and how to confirm the apparatus before reporting results.

SLOVENSKI STANDARD
01-oktober-2026
Izmenjevalniki toplote in vlage ter filtri dihalnih sistemov za dihalne pline - 2. del:
Merjenje izgube vlage (ISO/DIS 9360-2:2026)
Heat and moisture exchangers, and breathing system filters for respired gases - Part 2:
Measurement of moisture loss (ISO/DIS 9360-2:2026)
Anästhesie- und Beatmungsgeräte - Wärme- und Feuchtigkeitsaustauscher und
Atemschutzfilter (HMEF) zur Anfeuchtung von Atemgasen beim Menschen - Teil 2:
Messung von Feuchtigkeitsverlusten (ISO/DIS 9360-2:2026)
Titre manque — Partie 2: Titre manque
Ta slovenski standard je istoveten z: prEN ISO 9360-2
ICS:
11.040.10 Anestezijska, respiratorna in Anaesthetic, respiratory and
reanimacijska oprema reanimation equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 9360-2
ISO/TC 121/SC 2
Heat and moisture exchangers, and
Secretariat: ANSI
breathing system filters for respired
Voting begins on:
gases —
2026-08-20
Part 2:
Voting terminates on:
2026-11-12
Measurement of moisture loss
ICS: 11.040.10
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 has not been edited by the ISO Central 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 9360-2:2026(en)
DRAFT
ISO/DIS 9360-2:2026(en)
International
Standard
ISO/DIS 9360-2
ISO/TC 121/SC 2
Heat and moisture exchangers, and
Secretariat: ANSI
breathing system filters for respired
Voting begins on:
gases —
2026-08-20
Part 2:
Voting terminates on:
2026-11-12
Measurement of moisture loss
ICS: 11.040.10
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 has not been edited by the ISO Central Secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2026
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
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
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
ISO/DIS 9360-2:2026(en)
ii
ISO/DIS 9360-2:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Measurement of moisture loss . 2
4.1 Principle .2
4.2 Test apparatus.2
4.3 Test conditions .8
4.4 Procedure .8
5 Measurement of moisture loss from HME/HMEFs without a machine port .10
5.1 Principle .10
5.2 Test apparatus.10
5.3 Test conditions .10
5.4 Procedure .10
Annex A (informative) Lists of parts and specifications in Figure 1 and Figure 2.13
Annex B (informative) Rationale .15
Bibliography . 17

iii
ISO/DIS 9360-2:2026(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 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.
International Standard ISO 9360-2 was prepared by Technical Committee ISO/TC 121, Anaesthetic and
respiratory equipment, Subcommittee SC 2, Airway devices and related equipment.
ISO 9360 consists of the following parts, under the general title Breathing system filters for anaesthetic and
respiratory use:
— Part 1: Common requirements
— Part 2: Measurement of moisture loss
— Part 3: Measurement of filtration performance
These parts technically revise and replace ISO 9360-1:2000, ISO 9360-2:2001, ISO 23328-1:2008 and
ISO 23328-2:2009.
These parts are a combination of the above standards with new and modified requirements, in particular:
— Part 1 combines requirements from ISO 9360-1:2000 and ISO 23328-2:2009
— Part 2 combines requirements from ISO 9360-1:2000 and ISO 9360-2:2001
— Part 3 are requirements from ISO 23328-1:2008
Changes from the previous standards are:
— Corrected dimensions for the calibration HME and heated water bath side view

iv
ISO/DIS 9360-2:2026(en)
Introduction
The gases generally available for medical use lack sufficient moisture to be physiologically acceptable to
the respiratory tract of patients. Heat and moisture exchangers (HME) are used to raise the water content
and the temperature of the gas delivered to the respiratory tract of spontaneously and non spontaneously
breathing patients. HMEs are intended to form part of a ventilator breathing system. HME's are primarily
placed between the patient interface (e.g. Tracheal or Tracheostomy tube) and the anaesthesia or ventilator
breathing set. HME's are also intended for use with tracheostomy tubes where the HME is not designed to
connect to an anaesthesia or ventilator breathing set.

v
DRAFT International Standard ISO/DIS 9360-2:2026(en)
Heat and moisture exchangers, and breathing system filters
for respired gases —
Part 2:
Measurement of moisture loss
1 Scope
This document specifies requirements for the measurement of moisture loss from heat and moisture
exchangers (HMEs), including those incorporating breathing system filters (HMEFs), intended for the
humidification of respired gases for use primarily with patients with a tidal volume equal to or greater than
250 ml.
Breathing system filters (BSF) are also included in scope, as these devices do some amount of moisture to
inspired gases.
This document also includes requirements for the measurement of moisture loss from HMEs for use with
tracheostomized patients that do not have a machine port and having minimum tidal volumes of 250 mL.
Active HMEs are excluded from this document, the requirements for active HMEs are included in
[1]
ISO 80601-2-74:2026 .
NOTE 1 Wherever the term “device” is used in this document, it may either refer to HME, HMEF or BSF.
*** Add rationale why 250ml lower limit***
NOTE 2 HMEs, HMEFs that do not have a machine port for connection to a breathing tube are intended for patients
who are spontaneously breathing via a tracheostomy and do not require mechanical ventilation.
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 5356-1:2015, Anaesthetic and respiratory equipment — Conical connectors — Part 1: Cones and sockets
ISO 9360-1: 202X Heat and moisture exchangers, and breathing system filters for respired gases — Part 1:
Common requirements
ISO TS 24172, Alternative test method for heat and moisture exchangers
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 9360-1: 202X and the following
apply.
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/

ISO/DIS 9360-2:2026(en)
NOTE The terms given in Clause 3 are delineated throughout the text in italics.
4 Measurement of moisture loss
NOTE There is guidance or rationale for this subclause contained in Annex B.
4.1 Principle
The performance of the device shall be measured by recording the mass of water lost from the test apparatus
specified in 4.2.
NOTE An alternative method to determine heat and moisture exchanging efficiency can be found in ISO TS 24172.
4.2 Test apparatus
NOTE There is guidance or rationale for this subclause contained in Annex B.
The test apparatus (Figure 1) shall comprise the following components.
a) A bidirectional flow generator, which is a mechanically driven piston used to produce a flow having a
sinusoidal waveform.
b) A Humidity generator (HG), consisting of
1) a heated water bath (Figure 2) through which air is bubbled in both directions;
2) a rigid cylindrical reservoir (Figure 3) with a maximum volume of 7 L and a diameter of
approximately 150 mm, containing a 2 L reservoir bag;
3) a thermally insulated chamber (Figure 4), which contains the water bath, the reservoir and a heat
source.
c) An air delivery system (Figure 5), consisting of a T-piece with an internal diameter greater than 15 mm,
and an exhaust tube at least 200 mm in length.
d) Weighing equipment, with an accuracy of ± 0,1 g or better in the range of the mass to be measured.
e) Flowrate measuring equipment, with an accuracy of at least 5 % of the reading.
f) Calibration HME (Figure 6) consisting of a housing containing 81 polyvinyl chloride (PVC) tubes
arranged in a 9 × 9 array, each with an internal diameter of 2 mm, an external diameter of 4 mm, and a
length of 50 mm.
When the apparatus has been constructed and operated as specified in 4.4 the moisture loss from the
humidity generator with the calibration HME will be as shown in Table 2.

ISO/DIS 9360-2:2026(en)
Dimensions in millimetres
Key
1 to 19 see Annex A
20 sine wave generator inlet
21 air outlet
22 dry air supply 23 ± 1 °C, < 1 mg H O per litre air
23 weighing equipment
Figure 1 — Test apparatus side view

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