oSIST prEN ISO 9360-2:2026

• Status: Not Published
• Public Enquiry End Date: 30-Oct-2026
• ICS: 11.040.10 - Anaesthetic, respiratory and reanimation equipment
• Technical Committee: VAZ - Healthcare
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 04-Sep-2026
• Due Date: 22-Jan-2027
• Ref Project: prEN ISO 9360-2 - Heat and moisture exchangers, and breathing system filters for respired gases - Part 2: Measurement of moisture loss (ISO/DIS 9360-2:2026)

• Referred By: SIST 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: SIST EN ISO 12855:2025 - Electronic fee collection - Information exchange between service provision and toll charging (ISO 12855:2025)
• Effective Date: 28-Jan-2026
• Revises: SIST 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

oSIST prEN ISO 9360-2:2026 is the SIST draft Slovene standard aligned with ISO/DIS 9360-2:2026. It specifies how to measure moisture loss from heat and moisture exchangers (HMEs), HMEFs and breathing system filters (BSF) used with respired gases, so manufacturers and test laboratories can compare humidification performance under set breathing conditions.

What does oSIST prEN ISO 9360-2:2026 specify?

oSIST prEN ISO 9360-2:2026 specifies a test method for moisture loss from HMEs, HMEFs and BSF used with respired gases. It covers devices intended mainly for patients with a tidal volume of at least 250 mL, and it also covers HMEs for tracheostomized patients that do not have a machine port.

The document excludes active HMEs, which are covered by ISO 80601-2-74:2026. In practice, that means this part is for passive humidifying devices and related filters rather than electrically or actively driven humidifiers.

The document is organized into five clauses plus two informative annexes.

Annex	What it covers
Annex A	Lists of parts and specifications in Figures 1 and 2
Annex B	Rationale for the test method and design choices

Clauses 1 to 3 cover scope, normative references, and terms and definitions. Clauses 4 and 5 give the two measurement methods - one for devices with a machine port and one for devices without a machine port.

What are the key requirements of oSIST prEN ISO 9360-2:2026?

oSIST prEN ISO 9360-2:2026 measures performance by recording the mass of water lost from the humidity generator in the test rig. That matters because the device’s ability to retain moisture is translated into a repeatable laboratory measurement that can be compared across products and test conditions.

Test principle and apparatus

Clause 4.1 states that the device is assessed by measuring water mass loss from the humidity generator. Clause 4.2 defines the apparatus needed: a bidirectional flow generator, a humidity generator, an air delivery system, weighing equipment, flowrate measuring equipment, and a calibration HME.

This matters in practice because the method is tied to a specific rig, not to a general clinical setup. Laboratories need the same core components and the same assembly concept if they want comparable results.

Test conditions

Clause 4.3 requires the device to be tested within the manufacturer’s operating range, at the maximum tidal volume recommended by the manufacturer when that is above 1 L, at 10 breaths per minute, and with an inspiratory-to-expiratory ratio of 1:1. Clause 4.4 uses a defined set of breathing conditions in Table 1.

For a buyer or quality manager, this means the performance claim should be read against a controlled breathing pattern, not as a single universal number. It also means the manufacturer must state the operating range clearly enough for the test to be applied.

Procedure for devices with a machine port

Clause 4.4 requires the humidity generator to be connected, the rig to stabilize, and the air leaving the machine port to be confirmed against the chosen test condition. The procedure then records the initial mass, runs the test for the first hour, records the mass again, continues to the maximum recommended use time, and records the final mass.

The method then calculates moisture loss for the first hour and for the full test duration. In practice, this gives both an early performance point and a longer-use performance point, which are useful when comparing device claims.

Apparatus verification

Clause 4.4 also requires the test rig to be checked with the calibration HME. The rig is conditioned, then run with the calibration HME attached, and the resulting moisture loss must fall within the specified range for each test condition in Table 2.

This verification step matters because it confirms that the rig is behaving as intended before a product is tested. Without that check, moisture-loss results would be harder to trust or compare.

Procedure for devices without a machine port

Clause 5 adapts the same basic method for HMEs and HMEFs without a machine port by adding a test chamber. The air delivery system is connected to the test chamber, and the device is tested in the chamber rather than through a machine port.

Clause 5 also adds a case for devices that can provide supplemental oxygen. In that case, the test is repeated with the maximum oxygen flowrate recommended by the manufacturer, or with 10 L/min if no maximum is stated.

What terms does oSIST prEN ISO 9360-2:2026 define?

• HME - Heat and moisture exchanger, a device that helps return moisture and heat from exhaled gas to inspired gas.
• HMEF - Heat and moisture exchanger with breathing system filter function, combining humidification and filtration.
• BSF - Breathing system filter, included because it can also affect the moisture in inspired gases.
• HG - Humidity generator, the part of the test rig that produces the humidified gas used in the measurement.
• Machine port - The connection point used to attach the device to the breathing system test arrangement.
• I:E ratio - Inspiratory-to-expiratory ratio, the balance between inhalation and exhalation in the test waveform.
• Calibration HME - A reference HME used to confirm that the test apparatus gives repeatable moisture-loss results.

Who uses oSIST prEN ISO 9360-2:2026?

oSIST prEN ISO 9360-2:2026 is used by manufacturers of anaesthetic and respiratory equipment, test laboratories, and conformity assessment or quality assurance teams. It is also relevant to buyers and technical reviewers who need to compare humidification performance claims on HMEs, HMEFs and BSF.

The document is most useful when a team needs a common test method for product development, performance verification, supplier comparison, or acceptance testing. It is especially relevant in the anaesthetic, respiratory and reanimation equipment field.

What changed in oSIST prEN ISO 9360-2:2026 from the previous edition?

The foreword says this part technically revises and replaces ISO 9360-1:2000, ISO 9360-2:2001, ISO 23328-1:2008 and ISO 23328-2:2009. It also states that the change from the previous standards is corrected dimensions for the calibration HME and the heated water bath side view.

The foreword also notes that this part combines requirements from ISO 9360-1:2000 and ISO 9360-2:2001. In the series, Part 1 covers common requirements and Part 3 covers measurement of filtration performance.

Which standards are used with oSIST prEN ISO 9360-2:2026?

Standard	What it contributes
ISO 5356-1:2015	Conical connectors used in the test chamber and breathing-system connections
ISO 9360-1:202X	Common requirements and terms and definitions for the series
ISO TS 24172	An alternative test method for heat and moisture exchangers
ISO 80601-2-74:2026	Requirements for active HMEs, which are outside the scope of this part

What does the oSIST prEN ISO 9360-2:2026 document contain?

The document contains a main test method for devices with a machine port and a second method for devices without one. It includes a detailed test rig description, figures for the humidity generator and the test chamber, and tables that define the breathing test conditions and apparatus acceptance ranges.

It also includes calculation steps for moisture loss over the first hour and over the full recommended use time. Annex A lists the parts and example specifications for the illustrated components, while Annex B explains why the test waveform, chamber design and conditioning steps were chosen.

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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