ISO 11140-2:1998

INTERNATIONAL ISO
STANDARD 11140-2
First edition
1998-12-01
Sterilization of health care products —
Chemical indicators —
Part 2:
Test equipment and methods
Stérilisation des produits de santé — Indicateurs chimiques —
Partie 2: Appareillage et méthodes d’essai
A
Reference number
ISO 11140-2:1998(E)

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ISO 11140-2:1998(E)
Contents
1 Scope .1
2 Normative references .1
3 Definitions .1
4 Chemical Indicator Evaluating Resistometer (CIER).1
4.1 General.1
4.2 Steam chemical indicator resistometer.2
4.3 Ethylene oxide (EO) chemical indicator resistometer.3
4.4 Dry heat chemical indicator resistometer .4
4.5 Steam formaldehyde chemical indicator resistometer .5
4.6 Recording systems.6
©  ISO 1998
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
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© ISO
ISO 11140-2:1998(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.
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 11140-2 was prepared by Technical Committee ISO/TC 198, Sterilization of health care
products.
ISO 11140 consists of the following parts, under the general title Sterilization of health care products — Chemical
indicators:
 Part 1: General requirements
 Part 2: Test equipment and methods
 Part 3: Steam penetration test with user-assembled and preassembled test packs
 Part 4: Class 2 indicators for air-removal test
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© ISO
ISO 11140-2:1998(E)
Introduction
To test the performance of chemical indicators, with the exception of irradiation indicators, specific test equipment is
required. This part of ISO 11140 specifies the performance requirements for the test equipment to be used to establish
the response to the essential physical parameters. Irradiation indicators are generally tested in irradiation facilities.
The performance tolerances for equipment given in this part of ISO 11140 are intended to be suitable for testing any of
the classes of indicator specified in ISO 11140-1. Equipment operating with wider tolerances may be suitable for
specific applications.
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INTERNATIONAL STANDARD  © ISO ISO 11140-2:1998(E)
Sterilization of health care products — Chemical indicators —
Part 2:
Test equipment and methods
1 Scope
This part of ISO 11140 specifies requirements for the test equipment and methods to be used to test chemical
indicators for conformity to the requirements given in ISO 11140-1.
The test equipment and methods for ISO 11140-3 and ISO 11140-4 are specified in those parts.
This part of ISO 11140 does not specify requirements for test equipment or methods to be used to test Class 1
chemical indicators for ionizing irradiation sterilization for conformity to ISO 11140-1.
This part of ISO 11140 does not address safety aspects of the test equipment, because these are covered by specific
regional, national or local regulations.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this part of
ISO 11140. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties
to agreements based on this part of ISO 11140 are encouraged to investigate the possibility of applying the most
recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid
International Standards.
ISO 11140-1:1995, Sterilization of health care products — Chemical indicators — Part 1: General requirements.
ISO 11134:1994, Sterilization of health care products — Requirements for validation and routine control — Industrial
moist heat sterilization.
3 Definitions
For the purposes of this part of ISO 11140, the definitions given in ISO 11140-1 and the following definition apply.
3.1
come-up time
time elapsed from the commencement of steam admission to the attainment of the selected exposure conditions
4 Chemical Indicator Evaluating Resistometer (CIER)
4.1 General
The resistometer is intended to be used to expose test samples to stated test conditions.
The following specifications define the conditions to be achieved in proximity to the sample, but the means by which
these conditions are to be measured and controlled are not addressed.
NOTE Due to the required accuracy, automated control of the process parameters is recommended.
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ISO 11140-2:1998(E)
4.2 Steam chemical indicator resistometer
4.2.1 Performance requirements
4.2.1.1  The equipment shall be capable of maintaining the conditions given in table 1 within the limits given.
Table 1 — Tolerances and minimum ranges required
Temperature (110 to 145) °C 0,5 °C
–
Pressure (140 to 420) kPa – 3,5 kPa
Vacuum (4 to 100) kPa – 0,5 kPa
NOTE The pressure values given are the absolute pressures.
NOTE A lower absolute pressure in the vacuum phase may be required to test Class 5 and 6 indicators due to the partial
pressure of the retained air.
4.2.1.2  A timer covering 90 min with an accuracy of at least – 1 % of the exposure time shall be used for
measuring the exposure time for all steam indicators specified in ISO 11140-1.
4.2.1.3  The equipment shall be provided with means to evacuate the chamber to less than the vacuum setpoint to
permit adequate air removal prior to admission of steam. Steam admission to the chamber shall not be used to
effect air removal.
NOTE Some indicators can be adversely affected by prolonged exposure to dry heat and vacuum. The minimum
practicable settings for evacuation should be used, which normally should not exceed 5 min.
4.2.1.4  The chamber shall be so designed that condensate formed on colder parts of the chamber shall not affect
the test conditions.
NOTE This may require that the inner surfaces of the chamber and/or door are thermostatically controlled to the selected
operating temperature.
4.2.1.5  The chamber shall be supplied with saturated steam from a source external to the chamber. The steam
supply shall meet the requirements of ISO 11134.
4.2.1.6  Temperature and absolute pressure shall be monitored, recorded and verified to be within the required
accuracy limits for the selected exposure conditions as given in table 1.
4.2.1.7  The come-up time shall not exceed 10 s. During this come-up period, the time from 100 °C to the
attainment of the selected exposure temperature shall not exceed 5 s.
4.2.1.8  At the end of the exposure period, the time taken to attain atmospheric pressure in the CIER chamber shall
not exceed 5 s.
4.2.2 Procedure
4.2.2.1  Load the indicator on a suitable sample holder. The sample holder shall not affect the performance of the
indicator.
NOTE The sample holder should allow the indicator to be exposed to the test conditions in the manner intended by the
indicator manufacturer. Different indicators may require different designs of sample holders. Consult the indicator manufacturer
for guidance.
4.2.2.2  Before initiating a test cycle, heat the inner surface of the chamber to the required temperature.
With the loaded sample holder in the chamber, carry out the following sequence of operations.
4.2.2.3
a) Evacuate the chamber to the pre-exposure setpoint.
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ISO 11140-2:1998(E)
b) Admit steam to the chamber to obtain the required temperature and pressure.
c) Maintain the conditions for the required exposure time.
d) At the end of the exposure period, evacuate the chamber to a pressure not exceeding the post-exposure
setpoint and then admit air to ambient pressure.
4.2.2.4  On removal from the chamber, examine the indicator. The result shall be recorded with reference to the
selected exposure conditions (see 4.2.1.6).
4.3 Ethylene oxide (EO) chemical indicator resistometer
4.3.1 Performance requirements
4.3.1.1  The equipment shall be capable of maintaining the conditions given in table 2 within the limits given for
exposure periods between 1 min and 120 min.
Table 2 — Tolerances and minimum ranges required
Ethylene oxide concentration (200 to 1 200) mg/l – 5 %
Temperature (30 to 65) °C 1 °C
–
Relative humidity (RH) (20 to 85) % – (10 % · RH)
NOTE 1 The maximum EO concentration specified in table 2 will determine the operating pressure depending on the diluent
gases used, if any, and therefore operating pressure is not listed above.
NOTE 2 If this accuracy is not obtained (e.g. at low EO concentrations with the gas mixture containing less than 10 % EO),
the application should be restricted to specific indicator classes (e.g. process indicators) which require less accuracy.
4.3.1.2  A timer covering 120 min with an accuracy of at least – 1 % of the exposure time shall be used for
measuring the exposure time for all EO indicators specified in ISO 11140-1.
4.3.1.3  The equipment shall be provided with means to evacuate the chamber to a level less than 4 kPa to ensure
adequate dispersion of the sterilant and to exhaust the sterilant at the end of the exposure period.
4.3.1.4  The total time to achieve the required EO gas concentration surrounding the indicator and to reduce this
concentration to a level that will no longer affect t
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