ISO 11195:1995
(Main)Gas mixers for medical use — Stand-alone gas mixers
Gas mixers for medical use — Stand-alone gas mixers
Gives requirements for the performance and safety of stand-alone gas mixers intended for medical use and for connection to a medical gas supply system.
Mélangeurs de gaz à usage médical — Mélangeurs de gaz indépendants
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Standards Content (Sample)
INTERNATIONAL
ISO
STANDARD 11195
First edition
1995-10-01
Gas mixers for medical use - Stand-alone
gas mixers
Melangeurs de gaz 5 usage mbdical - M6langeurs de gaz inddpendants
Reference number
ISO 11195:1995(E)
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ISO 11195:1995(E)
Contents
Page
1
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1 Scope
1
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2 Normative references
1
3 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
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4 Gas connectors
2
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5 Normal operating conditions
2
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6 Reverse gas flow
2
7 Inlet filter- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
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8 Flow controls
2
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9 Leakage to atmosphere
............... 2
Low-pressure flexible connecting hose assemblies
IO
2
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11 Accuracy of operating data
3
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12 Gas supply failure
4
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13 Electrical safety
4
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14 Marking
4
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15 Accompanying documents
Annexes
A Test methods for alarm System, delivered gas and leakage to
6
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atmosphere
7
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B Rationales
0 ISO 1995
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronie or mechanical, rncluding photocopying and
microfilm, without Permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-l 211 Geneve 20 l Switzerland
Printed in Switzerland
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0 ISO
ISO 11195:1995~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. Esch 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.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 11195 was prepared by Technical Committee
lSO/TC 121, Anaesthetic and respiratory equipment, Subcommittee
SC 1, Beathing attachments and anaesthetic machines.
an integral part of this International Standard. Annex B is
Annex A forms
for information only.
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0 ISO
ISO 11195:1995(E)
Introduction
This International Standard specifies basic requirements for stand-alone
gas mixers intended for medical use. A known hazard associated with the
use of 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 tan Cause Patient injury.
As a consequence of this hazard, particular attention has been paid in this
International Standard to minimizing reverse flow. lt is recognized that in-
novations in design may appear which offer Performance advantages and
yet may conflict with specific design aspects of this International Standard.
Such innovations are not to be discouraged. If techniques and technolo-
gies advance beyond those in current usage, they should nevertheless
meet the safety and Performance requirements given in this International
Standard. If these techniques and technologies differ significantly from
those specified, this International Standard may be amended or revised to
encompass them.
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INTERNATIONAL STANDARD 0 ISO ISO 11195:1995(E,
Gas mixers for medical use - Stand-alone gas mixers
ISO 7767: 1988, Oxygen analyzers for monitoring pa-
1 Scope
tien t brea thing mixtures - Safe ty requiremen ts.
This International Standard gives requirements for the
ISO 9703-1: 1992, Anaesthesia and respiratory care
Performance and safety of stand-alone gas mixers in-
alarm Signals - Part 7: Visual alarm Signals.
tended for medical use and intended for connection
to a medical gas supply System. Rationales for some
ISO 9703-2: 1994, Anaesthesia and respiratory care
of the requirements are given in annex B.
alarm Signals - Part 2: Auditory alarm Signals.
This International Standard does not apply to
I EC 601-1: 1988, Medical electrical equipment -
Part 7: General requirements for safety.
a) blocks of flowmeters with separate controls for
the flow of each gas;
b) gas mixers which mix Oxygen with ambient air;
3 Definitions
c) gas mixers which depend on other medical de-
For the purposes of this International Standard, the
vices for functions required by this Standard.
following definitions apply.
3.1 stand-alone gas mixer; gas mixer: Device
which receives separate supplies of Oxygen and other
2 Normative references
medical gas(es) and which delivers the mixed gases
in concentrations adjustable by the Operator and
The following Standards contain provisions which,
which is not an integral component of any other
through reference in this text, constitute provisions
medical device.
of this International Standard. At the time of publi-
cation, the editions indicated were valid. All Standards
3.2 medical gas supply System
are subject to revision, and Parties to agreements
based on this International Standard are encouraged
(1) Non-flammable medical gas Pipeline System
to investigate the possibility of applying the most re-
comprising a central supply System, control equip-
cent editions of the Standards indicated below.
ment, a Pipeline distribution System and terminal units
Members of IEC and ISO maintain registers of cur-
at the Point where non-flammable medical gases or
rently valid International Standards.
vacuum may be required.
ISO 32:1977, Gas cylinders for medical use - Mark-
(2) Any other installation having no permanent pipe-
ing for iden tification of con ten t.
line System but employing a medical gas supply
Source complete with pressure regulators.
ISO 3744:1994, Acoustics - Determination of Sound
power levels of noise sources using Sound pressure
3.3 gas-specific: Having characteristics which pre-
- Engineering method in an essentially free field over
vent interchangeability, thereby allowing assignment
a reflecting plane.
to one gas or vacuum Service only.
ISO 5359: 1989, Low-pressure flexible connecting as-
semblies (hose assemblies) for use with medical gas 3.4 asarm: Indicator of an abnormal state or output
Systems. of a gas mixer.
1
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0 ISO
ISO 11195:1995(E)
4 Gas connectors 7 Met filter
Gas inlet connectors shall be gas-specific and shall be
Esch gas inlet shall be provided with a filter having a
either screw-threaded (i.e. NIST or DISS) or quick-
pore size not exceeding 100 Pm.
connect; they shall comply with ISO 5359.
NOTE 1 The outlet connector is not specified because
8 Flow controls
of the diversity of application of gas mixers.
For a rotary flow adjustment control, a counter-
5 Normal operating conditions
clockwise rotation shall Cause an increase in flow and,
conversely, a clockwise rotation shall Cause a de-
5.1 Normal operating conditions shall be with the crease in flow.
gas mixer connected to inlet gas supplies at all
The stem of each rotary flow control valve shall be
pressures and pressure differentials in the range
captive, so that it cannot be disengaged from its
stated by the manufacturer and at any setting of the
housing without the use of tools.
mixer control with either flow or no-flow conditions.
5.2 The gas mixer shall have an auditory alarm to
9 Leakage to atmosphere
indicate that the inlet pressure conditions are outside
the range of normal operating conditions specified by
Except for gas which is vented (bled) from the mixer
the manufacturer [see 15.2 p)]. If electrically pow-
by design, gas mixers shall not leak to atmosphere
ered, the alarm Signal shall be a medium priority alarm
by more than 50 mI/min (5,065 kPa I/min) when
complying with ISO 9703-2.
tested according to A.4.
NOTE 2 The gas mixer need not be provided with a
high-pressure alarm if the upper Iimit of the input pressure
specified by the manufacturer is higher than the normal
10 Low-pressure flexible connecting
maximum pressure provided by a medical gas Pipeline. The
hose assemblies
maximum gas pressure which a medical gas Pipeline con-
forming with ISO 7396:1987, Non-flammable medical gas
All external, operator-detachable inlet low-pressure
pipehe systems, will deliver in normal use is proposed, in
hose assemblies supplied with the gas mixer shall
the forthcoming new edition, to be 600 kPa.
comply with ISO 5359.
6 Reverse gas flow
11 Accuracy of operating data
6.1 Means shall be provided so that the reverse
flow of gas from each gas inlet to every other shall
not exceed IO mI/h (0,0169 kPa I/min) under normal
11.1 When tested according to A.2, the Oxygen
operating conditions or under any Single fault con-
concentration of the delivered gas shall be within
dition which is not alarmed. Test accordina to A.3.
+ 5 % (WV) of the indicated value. The tolerante shall
-
not result in an Oxygen concentration of less than
Means shall be provided so t lat the reverse gas
6.2
20 % (WV). The accuracy requirement shall apply only
other shall not ex-
flow from each gas inlet to every
to marked concentration values and not between
ceed 100 mI/min (IO,1 3 kPa I/min) during any Single
markings, unless otherwise stated by the manufac-
fault condition which is indicated by an alarm. Test
turer.
according to A.3.
11.2 When tested according to A.2, the gas mixer
6.3 The manufacturer shall maintain documentation
shall continue to function within the specified toler-
of methods by which compliance with 6.1 and 6.2 has
ances throughout the range of input pressure Variation
been verified, together with data supporting the val-
idity of the methods. stated by the manufacturer [see 15.2 a)].
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0 ISO ISO 11195:1995(L
12.2 Cut-Off devices for gases other than air
12 Gas supply failure
and Oxygen in the event of Oxygen supply
failure
12.1 Gas supply failure alarm
NOTE 3 See also 15.1 e).
12.2.1 The gas mixer shall be fitted with a gas cut-
off, which shall be activated when the Oxygen supply
pressure falls below the value stated in the in-
12.1.1 General
structions for use, and shall operate in one of the fol-
lowing ways:
12.1.1.1 The gas mixer shall have an alarm to indi-
cate failure of any one gas supply, whether the supply
a) tut off the supply of all gases other than air and
is derived from cylinders or from a Pipeline System.
Oxygen; or
This alarm shall be either gas-powered or electrically-
powered. If electrically-powered, it shall comply with
b) progressively reduce the flow of all other gases
the requirements for a high priority alarm given in
while maintaining the preset Oxygen flow until the
ISO 9703-1 and ISO 9703-2. The auditory alarm shall
supply of Oxygen finally fails, at which Point the
be automatically de-activated when the gas supply is
supply of all other gases shall be tut off; or
restored.
c) progressively reduce the flow of all other gases
while maintaining the preset Oxygen concen-
12.1.1.2 Electrically-powered alarms shall be operat-
tration until the Oxygen finally fails, at which Point
ive in the case of electrical power failure, except
the supply of all other gases shall be tut off.
when an electrical power failure alarm is fitted. Means
shall be provided for testing the alarm Systems.
12.2.2 Gases shall not be tut off before the gas
12.1.1.3 When tested in accordance with A.l, the
supply failure alarm is activated.
alarm shall be activated at the gas supply pressure
stated by the manufacturer [see 15.1 e)].
12.2.3 The sole means of resetting the gas tut-off
device shall be the restoration of the Oxygen supply
12.1.2 Gas mixers intended for mixing Oxygen
pressure to a level above that at which the gas tut-off
and nitrous Oxide
device is activated.
12.1.2.1 When tested in accordance with A.5, the
12.2.4 When tested in accordance with A-1, the gas
auditory alarm shall be of at least 7 s duration and,
tut-off device shall operate at the gas supply pressure
when tested as described in ISO 3744, its A-weighted
stated by the manufacturer [see 15.1 e)].
Sound pressure level sh
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