ISO 11195:2018
(Main)Gas mixers for medical use — Stand-alone gas mixers
Gas mixers for medical use — Stand-alone gas mixers
ISO 11195:2018 specifies requirements for the performance and safety of stand-alone gas mixers intended for mixing oxygen with another gas for medical use. ISO 11195:2018 does not apply to: a) blocks of flowmeters with separate controls for the flow of each gas; b) stand-alone gas mixers which mix oxygen with ambient air; c) stand-alone gas mixers with more than two different gas inlets; d) stand-alone gas mixers connected to an oxygen concentrator.
Mélangeurs de gaz à usage médical — Mélangeurs de gaz indépendants
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 11195
Second edition
2018-01
Gas mixers for medical use — Stand-
alone gas mixers
Mélangeurs de gaz à usage médical — Mélangeurs de gaz
indépendants
Reference number
ISO 11195:2018(E)
©
ISO 2018
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ISO 11195:2018(E)
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ISO 11195:2018(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 *Requirements for essential performance . 3
5 General requirements . 3
5.1 Risk management . 3
5.2 Usability . 3
6 Materials . 3
6.1 Biocompatibility . 3
6.2 Phthalates . 4
6.3 Natural rubber (latex) . 4
6.4 Effects of cleaning, disinfecting or sterilizing agents . 4
6.5 Gas compatibility . 4
6.6 Cleanliness . 5
6.7 Lubricants . 5
7 Normal operating conditions . 5
8 Requirements for gas supply inlet pressure . 5
9 Reverse gas flow . 5
10 *Leakage to atmosphere . 6
11 Alarm systems . 6
11.1 Electrically powered alarm system . 6
11.2 Non-electrically powered alarm system . 6
11.3 High pressure alarm condition . 6
11.4 Differential pressure alarm condition . 6
11.5 Gas supply failure alarm condition . 7
12 *Accuracy of indicated oxygen concentration . 7
13 Gas supply failure . 8
13.1 Oxygen . 8
13.2 Other medical gas (except air) . 8
13.3 Air/Oxygen . 8
14 Gas connectors . 8
14.1 Inlet connectors . 8
14.2 *Outlet connectors . 9
15 Inlet filter . 9
16 Flow controls . 9
17 Low-pressure hose assemblies . 9
18 Electrical safety . 9
19 Marking . 9
20 Accompanying documents .10
20.1 Instructions for use .10
20.2 Technical description .11
Annex A (informative) Rationale .14
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ISO 11195:2018(E)
Annex B (normative) Test methods for delivered gas, leakage to atmosphere and duration
of oxygen failure alarm systems .16
Annex C (informative) Index of defined terms .17
Bibliography .19
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ISO 11195:2018(E)
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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on 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 the following
URL: www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 121, Anaesthetic and respiratory
equipment, Subcommittee SC 1, Breathing attachments and anaesthetic machines.
This second edition cancels and replaces the first edition (ISO 11195:1995), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— scope has been amended by stating that this document applies to stand-alone gas mixers intended
for mixing oxygen with another gas for medical use and that it excludes stand-alone gas mixers
connected to an oxygen concentrator;
— definitions have been updated;
— requirements on essential performance have been identified;
— gas outlet connector has been specified for stand-alone gas mixers with an integral flow control;
— requirements for gas supply inlet pressure have been added;
— requirements on alarm conditions have been amended;
— requirements on reverse gas flow have been amended;
— requirements on gas supply failure have been restructured and amended;
— requirements on marking and accompanying documents have been amended.
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ISO 11195:2018(E)
Introduction
This document specifies basic requirements for stand-alone gas mixers intended for medical use.
A known hazard associated with the use of stand-alone gas mixers is the reverse flow of gas from
one gas inlet to another, resulting in the contamination of one gas supply system with another gas
and the delivery of an incorrect gas mixture that can cause patient injury. As a consequence of this
hazard, particular attention has been paid in this document to minimizing reverse flow. It is recognized
that innovations in design which offer performance advantages and yet may conflict with specific
design aspects of this document may appear. Such innovations are not to be discouraged. If techniques
and technologies advance beyond those in current usage, they should nevertheless meet the safety
and performance requirements given in this document. If these techniques and technologies differ
significantly from those specified, this document may be amended or revised to encompass them.
Rationales for some of the requirements of this document are given in Annex A. Such requirements are
indicated by the asterisk (*) after the clause number in the main text.
In this document, the following print types are used:
— requirements, compliance with which can be verified, and definitions: roman type;
— notes and examples: smaller roman type;
— test methods: italic type;
— terms defined in this document: small caps.
The attention of member bodies is drawn to the fact that equipment manufacturers and testing
organizations may need a transitional period following publication of a new, amended or revised ISO
or IEC publication in which to make products in accordance with the new requirements and to equip
themselves for conducting new or revised tests. It is the recommendation of the committee that the
content of this publication be adopted for implementation nationally not earlier than 3 years from
the date of publication for equipment newly designed and not earlier than 5 years from the date of
publication for equipment already in production.
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INTERNATIONAL STANDARD ISO 11195:2018(E)
Gas mixers for medical use — Stand-alone gas mixers
1 Scope
This document specifies requirements for the performance and safety of stand-alone gas mixers
intended for mixing oxygen with another gas for medical use.
This document does not apply to:
a) blocks of flowmeters with separate controls for the flow of each gas;
b) stand-alone gas mixers which mix oxygen with ambient air;
c) stand-alone gas mixers with more than two different gas inlets;
d) stand-alone gas mixers connected to an oxygen concentrator.
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 5359:2014, Anaesthetic and respiratory equipment — Low-pressure hose assemblies for use with
medical gases
ISO 7396-1, Medical gas pipeline systems — Part 1: Pipeline systems for compressed medical gases and vacuum
ISO 9170-1, Terminal units for medical gas pipeline systems — Part 1: Terminal units for use with
compressed medical gases and vacuum
ISO 10524-1, Pressure regulators for use with medical gases — Part 1: Pressure regulators and pressure
regulators with flow-metering devices
ISO 11114-3, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 3:
Autogenous ignition test for non-metallic materials in oxygen atmosphere
1)
ISO 14971:2012 , Medical devices — Application of risk management to medical devices
ISO 15001, Anaesthetic and respiratory equipment — Compatibility with oxygen
2)
IEC 60601-1:2012 +Amd 1:2012, Medical electrical equipment — Part 1: General requirements for basic
safety and essential performance
3)
IEC 60601-1-8:2006 +Amd 1:2012, Medical electrical equipment — Part 1-8: General requirements for
basic safety and essential performance — Collateral standard: General requirements, tests and guidance
for alarm systems in medical electrical equipment and medical electrical systems
EN 13544-2:2002, Respiratory therapy equipment — Part 2: Tubing and connectors
1) Under revision.
2) A consolidated edition, IEC 60601-1:2012, which includes IEC 60601-1:2005 and its amendment (IEC 60601-
1:2005/Amd 1:2012) is available.
3) A consolidated edition, IEC 60601-1-8:2006, which includes IEC 60601-1-8:2006 and its amendment (IEC
60601-1-8:2006/Amd 1:2012) is available.
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ISO 11195:2018(E)
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
alarm condition
state of the alarm system when it has determined that a potential or actual hazardous situation
exists for which operator awareness or response is required
Note 1 to entry: An alarm condition can be invalid, i.e. a false positive alarm condition.
Note 2 to entry: An alarm condition can be missed, i.e. a false negative alarm condition.
[SOURCE: IEC 60601-1-8:2006+Amd 1:2012, 3.1]
3.2
alarm limit
threshold used by the alarm system to determine an alarm condition
[SOURCE: IEC 60601-1-8:2006, 3.3]
3.3
alarm signal
type of signal generated by an alarm system to indicate the presence (or occurrence) of an alarm
condition
[SOURCE: IEC 60601-1-8:2006, 3.9]
3.4
alarm system
parts of ME equipment or ME system that detect alarm conditions and, as appropriate, generate
alarm signals
Note 1 to entry: The abbreviated terms ME equipment and ME system stand for medical electrical equipment
and medical electrical system, respectively.
[SOURCE: IEC 60601-1-8:2006, 3.11, modified — Note 1 to entry has been added.]
3.5
essential performance
performance necessary to achieve freedom from unacceptable risk
Note 1 to entry: Essential performance is most easily understood by considering whether its absence or
degradation would result in an unacceptable risk.
[SOURCE: IEC 60601-1:2005+Amd 1:2012, 3.27]
3.6
gas-specific
having characteristics which prevent connections between different gas services
[SOURCE: ISO 7396-1:2016, 3.17, modified — “or vacuum services” has been deleted.]
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ISO 11195:2018(E)
3.7
medical gas pipeline system
complete system which comprises a supply system, a monitoring and alarm system and a distribution
system with terminal units at the points where medical gases or vacuum are required
[SOURCE: ISO 7396-1:2016, 3.36]
3.8
stand-alone gas mixer
non-integrated device that can deliver an adjustable or fixed concentration of medical gas derived from
two separate medical gas supplies
4 *Requirements for essential performance
Essential performance requirements are found in the clauses listed in Table 1.
Table 1 — Distributed essential performance requirements
Requirement Clause
Maintaining the set concentration of oxygen, or generation of a 11, 12, 13
technical alarm condition
Maintaining the set flow, if applicable, or generation of a technical 11,13
alarm condition
Prevention of a hypoxic mixture or generation of a technical 11, 12, 13
alarm condition
Prevention of reverse gas flow from one inlet to the other 9
5 General requirements
5.1 Risk management
This document specifies requirements that are generally applicable to risks associated with stand-
alone gas mixers. An established risk management process complying with ISO 14971 shall be
performed for the stand-alone gas mixer and related accessories.
Compliance is checked by inspection of the risk management file.
5.2 Usability
The manufacturer shall apply a usability engineering process to assess and mitigate any risks in
normal use and use errors (see IEC 60601-1-6 and IEC 62366-1).
Check compliance by inspection of the usability engineering file.
6 Materials
6.1 Biocompatibility
Stand-alone gas mixers, in their ready-to-use state after any preparation recommended by the
manufacturer, shall satisfy the appropriate biocompatibility requirements (see ISO 18562 series).
Check compliance by inspection of the technical file.
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ISO 11195:2018(E)
6.2 Phthalates
Manufacturers of stand-alone gas mixers intended for the treatment of children or pregnant or
nursing women that include components made of materials that incorporate phthalates, which are
classified as carcinogenic, mutagenic or toxic to reproduction, shall provide a specific justification for
the use of these substances in their technical file. See also 19.6 d) and 20.1 for additional marking and
instructions for use requirements.
Check compliance by inspection of the marking, the instructions for use and the technical file.
6.3 Natural rubber (latex)
Manufacturers of stand-alone gas mixers that include components made of materials that
incorporate natural latex shall provide a specific justification for using these substances in their
technical file. See also 19.6 e) and 20.1 for additional marking and instruction for use requirements.
Check compliance by inspection of the marking, the instructions for use and the technical file.
6.4 Effects of cleaning, disinfecting or sterilizing agents
The recommended cleaning, disinfecting or sterilizing agents shall not alter the specified performance
of the device throughout the expected service life. See also 20.1 m).
Check compliance by inspection of the instructions for use and the technical file.
6.5 Gas compatibility
6.5.1 *The materials in contact with the gases, during normal use, shall be resistant to corrosion
and compatible with oxygen and the other gases and their mixtures in the temperature range of −20 °C
to +60 °C.
NOTE 1 Corrosion resistance includes resistance against moisture and surrounding materials.
NOTE 2 Compatibility with oxygen involves both combustibility and ease of ignition. Materials that burn in
air burn violently in pure oxygen. Many materials that do not burn in air will do so in pure oxygen, particularly
under pressure.
Similarly, materials that can be ignited in air require lower ignition energies in oxygen. Many such
materials can be ignited by friction at a valve seat or by adiabatic compression produced when oxygen
at high pressure is rapidly introduced into a system initially at low pressure.
NOTE 3 ISO 15001 contains information on selection of metallic and non-metallic materials and other aspects
of compatibility of equipment with oxygen.
6.5.2 The auto-ignition temperature of the non-metallic components in contact with the gas, including
the sealing materials and lubricants (if used), as determined in accordance with ISO 11114-3, shall be
not lower than 160 °C.
Check compliance by inspection of the technical file.
NOTE 1 Regional or national regulations might require the provision of evidence to a competent authority or
conformity assessment body (e.g. notified body in the European Economic Area) upon request.
NOTE 2 The maximum permitted operating temperature of tested material is 100 °C lower than the auto-
ignition temperature at the corresponding oxygen pressure. This safety margin is necessary because it covers
both an unforeseen increase in the operating temperature and the fact that the auto-ignition temperature is not a
constant. Values of the auto-ignition temperature always depend on the test method used, which does not exactly
simulate all possible operating conditions.
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ISO 11195:2018(E)
6.5.3 Springs, highly strained components and parts liable to wear which come in contact with the gas
shall not be plated.
NOTE Plating could come off.
Check compliance by inspection of the technical file.
6.6 Cleanliness
Components of stand-alone gas mixers in contact with medical gases during normal use shall meet
the cleanliness requirements of ISO 15001.
Check compliance by inspection of the technical file.
6.7 Lubricants
If lubricants are used, they shall be compatible with oxygen, the other medical gases and their mixtures
in the temperature range specified in 6.5.1 up to the test pressure of 1 000 kPa.
Check compliance by inspection of the technical file.
7 Normal operating conditions
Normal operating conditions shall be with the stand-alone gas mixer connected to the inlet
gas supplies at all pressures and pressure differentials in the range stated by the manufacturer
[see 20.2 p)] and at any setting of the stand-alone gas mixer control with either flow or no-flow
conditions.
8 Requirements for gas supply inlet pressure
The stand-alone gas mixer shall operate and meet the requirements of this document throughout the
rated range of gas supply inlet pressures and shall not cause an unacceptable risk under the single
fault condition to a maximum pressure of 1 000 kPa (10 bar).
If the stand-alone gas mixer is intended to be connected to either
— a medical gas pipeline system complying with ISO 7396-1 via terminal units complying with
ISO 9170-1 and flexible hose connections complying with ISO 5359, or
— a pressure regulator complying with ISO 10524-1, then
the rated range of gas supply inlet pressures shall cover the range specified in those standards.
NOTE Internal pressure regulators can be required to accommodate the rated range of gas supply inlet
pressure and the single fault condition of maximum gas supply inlet pressure.
The gas shall continue to flow to the patient under a single fault condition of overpressure. Under
this condition the flowrate may be out of specification.
Check compliance by functional testing in normal operating condition with the most adverse operating
settings and inspection of the technical file.
9 Reverse gas flow
The reverse flow of gas from one gas inlet to the other shall not exceed 10 ml/h under normal operating
conditions and single fault condition.
*The manufacturer shall maintain documentation of methods by which compliance with this
requirement has been verified, together with data supporting the validity of the methods.
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ISO 11195:2018(E)
Check compliance by functional testing, inspection of the technical file and the instructions for use [see 20.1 b)].
10 *Leakage to atmosphere
Stand-alone gas mixers shall not leak to atmosphere by more than 50 ml/min.
NOTE This does not include gas vented to atmosphere by design
Gas vented to atmosphere by design (bleed flow) shall be restricted to oxygen and/or air.
Check compliance by the test given in B.2.
11 Alarm systems
11.1 Electrically powered alarm system
If an alarm system is electrically powered it shall:
a) comply with IEC 60601-1-8;
b) indicate if the supply mains has failed;
c) if equipped with a reserve electrical power source, provide an indication that it is operating from
the reserve electrical power source.
Check compliance by inspection and functional testing.
11.2 Non-electrically powered alarm system
A non-electrically powered alarm system shall generate auditory alarm signals with an A-weighted
sound pressure level at least 2 dB above a background white noise level of 55 dB as measured by the
method of ISO 3744.
Check compliance by inspection and functional testing with the method of ISO 3744.
11.3 High pressure alarm condition
The stand-alone gas mixer shall ge
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