prEN ISO 11140-3

SLOVENSKI STANDARD
01-september-2025
Sterilizacija izdelkov za zdravstveno nego - Kemijski indikatorji - 3. del: Indikatorji
tipa 2 za uporabo pri Bowie-Dickovem preskusu prodiranja pare (ISO/DIS 11140-
3:2025)
Sterilization of health care products - Chemical indicators - Part 3: Type 2 indicators for
use in the Bowie and Dick-type steam penetration test (ISO/DIS 11140-3:2025)
Sterilisation von Produkten für die Gesundheitsfürsorge - Chemische Indikatoren - Teil 3:
Indikatorsysteme der Klasse 2 zur Verwendung im Bowie-Dick-Dampfdurchdringungstest
(ISO/DIS 11140-3:2025)
Stérilisation des produits de santé - Indicateurs chimiques - Partie 3: Indicateurs de Type
2 pour utilisation lors de l'essai de Bowie et Dick de pénétration de la vapeur (ISO/DIS
11140-3:2025)
Ta slovenski standard je istoveten z: prEN ISO 11140-3
ICS:
11.080.01 Sterilizacija in dezinfekcija na Sterilization and disinfection
splošno in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 11140-3
ISO/TC 198
Sterilization of health care
Secretariat: ANSI
products — Chemical indicators —
Voting begins on:
Part 3: 2025-07-29
Type 2 indicators for use in
Voting terminates on:
2025-10-21
the Bowie and Dick-type steam
penetration test
Stérilisation des produits de santé — Indicateurs chimiques —
Partie 3: Indicateurs de Type 2 pour utilisation lors de l'essai de
Bowie et Dick de pénétration de la vapeur
ICS: 11.080.20
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 is circulated as received from the committee 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 11140-3:2025(en)
DRAFT
ISO/DIS 11140-3:2025(en)
International
Standard
ISO/DIS 11140-3
ISO/TC 198
Sterilization of health care
Secretariat: ANSI
products — Chemical indicators —
Voting begins on:
Part 3:
Type 2 indicators for use in
Voting terminates on:
the Bowie and Dick-type steam
penetration test
Stérilisation des produits de santé — Indicateurs chimiques —
Partie 3: Indicateurs de Type 2 pour utilisation lors de l'essai de
Bowie et Dick de pénétration de la vapeur
ICS: 11.080.20
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 is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
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: +41 22 749 01 11
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 11140-3:2025(en)
ii
ISO/DIS 11140-3:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General . 3
5 Requirements . 3
6 Indicator format . 4
7 Performance requirements . . 4
8 Packaging and labelling . 5
Annex A (normative) Estimation of visual difference between colour of the substrate and of the
changed or unchanged indicator system by determination of relative reflectance density . 7
Annex B (normative) Determination of uniform colour change on exposure to saturated steam .11
Annex C (normative) Determination of non-uniform colour change on exposure to a reference
fault condition . .12
Annex D (normative) Reproducibility and determination of the reference fault condition in the
standard test pack . . 14
Annex E (normative) Determination of indicator colour change on exposure to dry heat .18
Annex F (normative) Determination of shelf life of indicators . 19
Annex G (normative) Determination of transfer of indicator to standard test pack on processing .20
Annex H (normative) Steam exposure apparatus and steam for test purposes .21
Annex I (normative) Standard test pack .24
Annex J (normative) Air injection system . .25
Annex K (informative) Relationship between chemical indicator components .27
Annex ZA (informative) Relationship between this European Standard and the General Safety
and Performance Requirements of Regulation (EU) 2017/745 aimed to be covered .28
Bibliography .31

iii
ISO/DIS 11140-3:2025(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).
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 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.
This document was prepared by Technical Committee ISO/TC 198, Sterilization of health care products.
This third edition cancels and replaces the second edition (ISO 11140-3:2007), which has been technically
revised.
The main changes are as follows:
— change of title from class 2 indicator to type 2 indicator to align with ISO 11140-1;
— correct use of the terms indicator and indicator system to align with ISO 11140-1;
— updated normative references;
— inserted common Clause 4 for ISO/TC 198 documents, replacing Clause 8;
— aligned indicator labelling with ISO 11140-4;
— aligned Annex B with ISO 11140-4;
— modified Annex D to allow same methods of creating reference fault condition as ISO 11140-4;
— moved Annex F to Annex E;
— added Annex L, modified from ISO 11140-1.
A list of all parts in the ISO 11140 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
ISO/DIS 11140-3:2025(en)
Introduction
[1]
The Bowie and Dick test is a test for steam sterilizers for products to be sterilized that are within sterile
barrier systems or other porous loads. As such it is performed during the demonstration of conformance of
steam sterilizers to EN 285 and as a routine test in ISO 17665. The test method is described in EN 285.
A failure of the Bowie and Dick test is symptomatic of a number of potential problems with the sterilizer that
could compromise the uniform sterilization of a load to be processed. This failure is not conclusive proof
that the fault in the sterilizer is due to air retention, air leakage or non-condensable gases, and it can be
necessary to investigate other causes of failure.
The Bowie and Dick test was conceived as a test for successful steam penetration into a standardised test
[1]
load in high-vacuum porous-load sterilizers used in the sterilization of health care products. A successful
Bowie and Dick test indicates sufficient air removal to facilitate rapid and even penetration of steam into
the test load. A failure of the Bowie and Dick test is symptomatic of a number of potential problems with the
sterilizer that could compromise sterilization of the load. The presence of air within the load may be due to
an inefficient air removal stage, an air leak during the air removal stage, or non-condensable gases in the
steam supply, are circumstances that can lead to failure of the test. This failure is not conclusive proof that
the fault is due to air retention, air leakage or non- condensable gases, and it can be necessary to investigate
other causes of failure.
The result of the test can also be affected by other factors which inhibit steam penetration. The test does
not necessarily demonstrate either achievement of the required temperature or maintenance of that
temperature for the required time to achieve sterilization.
In this document, the Bowie and Dick test consists of two components:
a) a small, standardised test load;
b) a chemical indicator to detect the presence of steam.
[1]
The Bowie and Dick test as originally described utilized huckaback towels as the material for the test
load. The test as described in EN 285 uses cotton sheets for this purpose.
Because a range of different tests in different countries has historically been termed the Bowie and Dick test,
the term “Bowie and Dick-type test” is used in this document. Further information is given in ISO 15882.

v
DRAFT International Standard ISO/DIS 11140-3:2025(en)
Sterilization of health care products — Chemical indicators —
Part 3:
Type 2 indicators for use in the Bowie and Dick-type steam
penetration test
WARNING — The use of this document can involve hazardous materials, operations and equipment. It
is the responsibility of the user of this document to establish appropriate safety and health practices
and determine the applicability of any other restrictions prior to use.
1 Scope
This document specifies the requirements for a Type 2 chemical indicator to be used in the steam penetration
test for steam sterilizers for wrapped health care goods (instruments, etc., and porous materials).
Chemical indicators conforming with this document are intended for use in combination with the standard
test pack as described in EN 285. This document does not consider the performance of the standard test
pack, but does specify the performance of the chemical indicator.
NOTE The Bowie and Dick-type test is used for routine testing of steam sterilizers and validation of steam
sterilization processes.
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.
EN 285:2015+A1:2021, Sterilization — Steam sterilizers — Large sterilizers
ISO 5457:1999/Amd 1:2010, Technical product documentation — Sizes and layout of drawing sheets
ISO 5636-3:2013, Paper and board — Determination of air permeance (medium range) — Part 3: Bendtsen method
ISO/CIE 11664-2:2022, Colorimetry — Part 2: CIE standard illuminants
ISO 11140-1:2014, Sterilization of health care products — Chemical indicators — Part 1: General requirements
IEC 60584-1:2013, Thermocouples — Part 1: EMF specifications and tolerances
IEC 60751:2022, Industrial platinum resistance thermometers and platinum temperature sensors
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11140-1 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 11140-3:2025(en)
3.1
chamber reference temperature
temperature at a specified point within the chamber
Note 1 to entry: The specified point is usually located in the chamber drain or active chamber discharge of the steam
exposure apparatus.
[SOURCE: ISO 11139:2018/Amd 1:2024, 3.38, modified – Note 1 to entry has been added.]
3.2
chemical indicator
test system that reveals change in one or more pre-specified process variables based on a chemical or
physical change resulting from exposure to a process
Note 1 to entry: See Annex K.
[SOURCE: ISO 11139:2018/Amd 1:2024, 3.43, modified – Note 1 to entry has been added.]
3.3
chemical indicator system
combination of a chemical indicator (3.2) and a specific test load
Note 1 to entry: See Annex K.
[SOURCE: ISO 11139:2018, 3.43.1/Amd 1:2024, modified – Note 1 to entry has been added.]
3.4
exposure time
period for which the chamber reference temperature lies within the sterilization temperature band
3.5
reference fault period
period of 30 s commencing when the chamber reference temperature attains the set operating temperature
3.6
sterilization temperature
minimum temperature on which the evaluation of sterilization efficacy is based
Note 1 to entry: This is the minimum temperature of the sterilization temperature band.
Note 2 to entry: The use of the word sterilization within this and other definitions is not intended to imply that
sterilizing conditions will take place under the test cycle conditions.
[SOURCE: ISO 11139:2018/Amd 1:2024, 3.286, modified – Note 1 to entry and note 2 to entry have been
added.a]
3.7
temperature band
range of temperatures expressed as the minimum and maximum temperatures which prevail during the
specified period of a cycle
Note 1 to entry: These temperatures are usually stated in whole units.
[SOURCE: ISO 11139:2018, 3.293/Amd 1:2024, modified – Note 1 to entry has been added.]
3.8
temperature depression
thermodynamic temperature difference in kelvin (Celsius) given by (chamber reference temperature, in
Celsius) minus (temperature in the standard test pack, in Celsius)
EXAMPLE 2 K (2 °C).
ISO/DIS 11140-3:2025(en)
3.9
test equilibration time
time elapsed after the chamber reference temperature attains the set operating temperature
until the temperature within the standard test pack is the same as the chamber reference temperature
[SOURCE: ISO 11139:2018/Amd 1:2024, 3.297]
4 General
4.1 The development, validation and routine control of a sterilization process is a critical element in
product realization of health care product. To ensure the consistent implementation of the requirements
specified in this document, the necessary processes need to be established, implemented and maintained.
Processes of particular importance in relation to the development, validation and routine control of a
sterilization process include but are not limited to:
— control of documentation, including records,
— assignment of management responsibility,
— provision of adequate resources, including competent human resources and infrastructure,
— control of product provided by external parties,
— identification and traceability of product throughout the process, and
— control of non-conforming product.
NOTE ISO 13485 covers all stages of the lifecycle of medical devices in the context of quality management
systems for regulatory purposes. National and/or regional regulatory requirements for the provision of health care
product can require the implementation of a full quality management system and the assessment of that system by a
recognized conformity assessment body.
4.2 A process shall be specified for the calibration of all equipment, including instrumentation for test
purposes, used in meeting the requirements of this document.
5 Requirements
5.1 Unless specified otherwise in this document, the requirements of ISO 11140-1 shall apply.
5.2 Test samples shall be conditioned to 23 °C ± 1 °C and 50 ± 2 % RH prior to testing for performance.
5.3 The indicator shall have sufficient strength to withstand steam sterilization and subsequent handling.
5.4 A thermometric recording instrument(s) shall be used in conjunction with temperature sensors to
record the temperatures measured in the locations specified in the tests described in this document. The
temperature-measuring equipment used in all test methods for demonstrating conformance with this
document shall meet the following requirements:
a) Temperature sensors shall be either platinum resistance and conform with Class A of IEC 60751:2022,
5.2.3.1, or a thermocouple and conform with one of the tables of tolerance class 1 of IEC 60584-1:2013,
Clause 5.
b) The performance characteristic of the temperature sensor shall not be affected by the environment in
which it is used, e.g. pressure, steam or vacuum.
c) The temperature sensors shall have a response time in water of Ʈ ≤ 0,5 s.
ISO/DIS 11140-3:2025(en)
d) The temperature measured by all temperature sensors when immersed in a temperature source at a
temperature known to within ±0,1 K (±0,1 °C), and within the sterilization temperature band, shall not
differ by more than 0,5 K (0,5 °C).
e) The recording instrument shall record the temperature from a minimum of 6 sensors. The sampling
interval shall not exceed 2,5 s. All data sampled shall be used for the interpretation of results.
f) The scale range shall include 0 °C to 150 °C. For analogue instruments, the minor mark interval shall
not exceed 1 K (1 °C), the resolution shall be not less than 0,5 K (0,5 °C) and the chart speed shall be not
less than 15 mm/min. Digital instruments shall register and record in increments of not more than 0,1 K
(0,1 °C).
g) The limit of error of the recording instrument between 0 °C and 150 °C (excluding temperature sensors)
shall not exceed 0,25 % when tested in an ambient temperature of (20 ± 3) °C. The additional error due
to change in the environmental temperature shall not exceed 0,04 K/K (0,04 °C/ °C).
h) Calibration shall be carried out using a working or reference standard that is traceable to a national
standard or a primary standard. The thermometric recording instrument shall have a valid test
certificate.
i) The calibration instrument shall have a valid test certificate.
6 Indicator format
The format of the chemical indicator shall meet the following requirements.
a) The indicator reagent shall be distributed to cover not less than 30 % of the surface area of the substrate.
The distance between adjacent areas of indicator reagent shall not exceed 20 mm.
The pattern of indicator reagent distribution should permit clear interpretation of the colour change at
the margin with the colour change in the central region.
b) It shall have an air porosity not less than 1,7 µm/(Pa.s) when tested in accordance with ISO 5636-3:2013,
Clause 10 at an air pressure of 1,47 kPa.
c) The indicator substrate shall have a colour which is uniform to visual observation.
d) The indicator shall have a difference in relative reflectance density of not less than 0,3 between the
colour of the indicator substrate and either the changed indicator or unchanged indicator as specified
[see ISO 11140-1:2014, 5.8 c)].
Conformance shall be tested in accordance with Annex A.
e) It shall permit writing in permanent ink to be made legibly on both processed and unprocessed
materials. Markings made before processing shall be legible after processing.
f) It shall be of size A4 in accordance with ISO 5457:1999/Amd 1:2010, 3.1.
7 Performance requirements
7.1 The indicator, when tested in combination with the standard test pack specified in Annex I, shall:
a) show a uniform colour change conforming with 6 d) after exposure to a non-fault operating cycle at an
exposure time of 3,5 min at 134 °C, or an exposure time of 15 min at 121 °C, or at any other time/
temperature combination specified by the manufacturer when the temperature tolerance shall be
+°15,C
and the time tolerance shall be ±5 s.
0°C
Conformance shall be tested in accordance with Annex B.

ISO/DIS 11140-3:2025(en)
b) show a non-uniform colour change when exposed to the reference fault condition (see Annex D) where
a concentration of residual, induced or injected air or non-condensable gases is created in the standard
test pack.
Conformance shall be tested in accordance with Annex C.
7.2 The indicator shall show no discernible colour change after exposure to dry heat at (140 ± 2) °C for not
less than 30 min.
With some indicators, a slight colour change can occur after exposure to dry heat; this shall be acceptable
if the change that occurs is slight or markedly different from that brought about by exposure to steam in
accordance with 7.1 a) and within the limits specified in the instructions for use (see ISO 11140-1:2014, 5.8).
Conformance shall be tested in accordance with Annex E.
7.3 The indicator shall not visibly transfer chemical indicator reagent to the material of the test load in
intimate contact with the indicator during processing.
Conformance shall be demonstrated in accordance with Annex G.
7.4 The indicator shall conform with the requirements of this document for the duration of the shelf life
specified [see ISO 11140-1:2014, 5.8 j)].
If any change in the indicator occurs during ageing, it shall be different from the change on exposure to
saturated steam [as described in 7.1 a)] and shall either inactivate the indicator so that no further change
can take place or not affect the performance of the indicator according to 7.1 a) and 7.1 b).
Conformance shall be tested in accordance with Annex F.
8 Packaging and labelling
8.1 Each indicator shall be marked with:
a) the sterilization temperature(s) at which the product is designed to be used (see ISO 11140-1:2014, 5.7);
b) a unique code from which the manufacturing history can be traced [see ISO 11140-1:2014, 5.8 k)];
c) the expiry date under the specified storage conditions [see ISO 11140-1:2014, 5.8 j)];
d) at least the information summarized in Figure 1.
Adjacent to each heading there shall be a clear space not less than 5 mm × 20 mm for the user to enter the
required information at the time of use or, if the size of the indicator does not permit this, each indicator
shall be supplied with a means of retaining the indicator as a permanent record which shall be printed with
the information given in Figure 1. The means of retention shall permit writing in permanent ink to be made
in association with the indicator.

ISO/DIS 11140-3:2025(en)
NOTE This is an example of a suitable format. Other formats and/or text can be used.
Figure 1 — Provision for recording information to be provided on or with each indicator
8.2 The product shall be packed in such a way as to allow easy separation of individual units of product
and to protect the product from moisture, dust, sunlight and damage in normal transit, to the extent
necessary to ensure that the indicator retains its performance throughout the stated shelf life when stored
in accordance with the instructions for use.
Conformance shall be tested by inspection of the technical documentation.
8.3 The outside of each indicator primary pack shall be marked with the sterilization temperature(s) at
which the product is suitable for use.
8.4 The information supplied (see ISO 11140-1:2014, 5.8) shall include sufficient instructions on the use of
the indicator system to enable correct interpretation of the test results.
8.5 When requested by the purchaser, a certificate of conformity to the requirements of this document for
each lot of product supplied shall be available.
8.6 The information supplied may take the form of internationally recognised symbols. See, for example,
ISO 15223-1.
8.7 The product shall be identified with a unique identification or UDI carrier (see ISO 11140-1:2014, 5.8).

ISO/DIS 11140-3:2025(en)
Annex A
(normative)
Estimation of visual difference between colour of the substrate and
of the changed or unchanged indicator system by determination of
relative reflectance density
A.1 Principle
The relative reflectance density of the changed indicator and the substrate shall be determined in accordance
with the method given in A.3.
NOTE This method is based on ISO 5-1, ISO 5-3 and ISO 5-4.
Relative reflectance density, D , is calculated as follows:
Rf
DR=−log (A.1)
Rf 10 f
Φ
c
R = (A.2)
f
Φ
ce
where
Φ is the reflected flux from the indicator;
c
Φ is the reflected flux from the substrate;
ce
To completely define a type of density spectrally, it is necessary to specify the light source, optics and
spectral response of the measuring system.
A.2 Apparatus
A.2.1 Steam exposure apparatus, as specified in Annex H.
A.2.2 Illuminant D , with a relative spectral power distribution, as specified in ISO 11664-2:2022,
Clause 5.
A.2.3 Photoelectric reflectance photometer, giving within 0,3 % an indicated reading proportional to the
intensity of light reflected from the surface under test. The instrument has the following characteristics.
A.2.3.1 Optical geometry
The optical geometry shall include illumination of the specimen at angles between 40° and 50°, viewed along
the normal (0°) with an angle of acceptance (observer angle) of 10°.
The dimensions of the measurement aperture of the instrument shall permit the measurement aperture to
be entirely filled with substrate or indicator reagent.
To minimize measurement errors, the optical system should be equipped with a polarizing filter if the
surface to be measured is highly reflecting, e.g. a plastic-coated surface.

ISO/DIS 11140-3:2025(en)
A.2.3.2 Spectral response
For the visual reflectance density, the combined spectral sensitivity of the receiver and spectral
characteristics of the components on the efflux section of the measuring instrument shall match the spectral
luminance efficiency in photopic vision, designated V . The product of V and the reflection densitometer
(λ) (λ)
illuminance E , wavelength by wavelength, defines the spectral products required of the measuring
A
instrument in order to provide comparison of visual densities. The spectral product of the measuring
instrument shall be within ±20 % of the values given in Table A.1.
NOTE These conditions assume that there is no fluorescence in the optical elements of the instrument or the sample.
A.2.3.3 Calibration
Reflectance density is determined using a perfectly-reflecting and perfectly-diffusing material as a reference
standard. Such a material does not exist, but the response that would theoretically be obtained from such a
material can be compared with a suitable secondary reference standard, e.g. compressed barium sulfate or
enamelled metal plaques which can then be used to calibrate the densitometer.
The measuring instrument shall be calibrated against reference samples previously calibrated by a National
Reference Laboratory.
The instrument shall indicate values within ±3 % of the calibrated values of the reference samples.
A.2.3.4 Background
While readings of the reflectance density of the substrate and the indicator are being made, the sample shall
be in contact with a backing material which is spectrally non-selective and diffuse-reflecting.
A.3 Test method
A.3.1 Sample conditioning
Samples shall be conditioned to, and in equilibrium with, (23 ± 2) °C and (50 ± 5) % relative humidity
when tested.
NOTE Standardized conditions are recommended because some materials change density with variations in
temperature and relative humidity.
A.3.2 Procedure
Expose the indicator within the standard test pack to a cycle of the steam exposure apparatus at the specified
operating temperature for the indicator system, to produce a uniform colour change in the indicator reagent
in accordance with 7.1 a).
Determine the relative reflectance density of the indicator reagent on the substrate by using the substrate
as the reference reflectance.
Carry out this measurement on three samples for each of three lots of the indicator.
A.4 Test report
The test report shall contain at least the following information:
a) name and address of the indicator manufacturer;
b) batch numbers of the individual batches of indicator tested;
c) make, model and serial number of the test instrument;
d) calibration details traceable to a national standards authority;

ISO/DIS 11140-3:2025(en)
e) temperature chart records of the steam exposure to which the indicators were exposed;
f) mean and range of the relative reflectance density measurements;
g) date of test;
h) identification of the test operator.
Table A.1 — Values of spectral product required of the reflectance photometer at the given values of
wavelength and illuminance
Wavelength Reflection densitometer illuminance Visual density spectral product
nm E Π
A ν
340 4
350 5
360 6
370 8
380 10
390 12
400 15 < 1 000
410 18 1 322
420 21 1 914
430 25 2 447
440 29 2 811
450 33 3 090
460 38 3 346
470 43 3 582
480 48 3 818
490 54 4 041
500 60 4 276
510 66 4 513
520 72 4 702
530 79 4 825
540 86 4 905
550 93 4 957
560 100 4 989
570 107 5 000
580 114 4 989
590 122 4 956
600 129 4 902
610 136 4 827
620 144 4 731
630 151 4 593
640 158 4 433
650 165 4 238
660 172 4 013
670 179 3 749
680 185 3 490
690 192 3 188
ISO/DIS 11140-3:2025(en)
TTabablele A A.11 ((ccoonnttiinnueuedd))
Wavelength Reflection densitometer illuminance Visual density spectral product
nm E Π
A ν
700 198 2 901
710 204 2 622
720 210 2 334
730 216 2 041
740 222 1 732
750 227 1 431
760 232 1 146
770 237 ≤ 1 000
ISO/DIS 11140-3:2025(en)
Annex B
(normative)
Determination of uniform colour change on exposure to saturated steam
B.1 Apparatus
B.1.1 Steam exposure apparatus, as specified in Annex H.
B.1.2 Standard test pack, as specified in Annex I.
B.1.3 Temperature sensors and thermometric recording instruments, as specified in the requirements for
test instrumentation given in 5.4.
B.2 Procedure
B.2.1 Insert thermocouples in accordance with EN 285 into the standard test pack in accordance with
Annex I. Insert the indicator to be tested into the centre of the standard test pack. Expose the indicator
combined with the standard test pack to a cycle of the steam exposure apparatus with the holding time and
temperature pre-set to those specified in 7.1 a). At the commencement of the plateau period, the difference
between the measured temperature in the drain of the steam exposure apparatus and in the centre of the
test pack shall be less than 0,5 K (0,5 °C) and shall be so maintained throughout the plateau period in order
that the test remain valid.
B.2.2 At the end of the operating cycle, remove the standard test pack from the steam exposure apparatus
and remove the indicator. Examine the indicator for conformance with 7.1 a).
B.2.3 Repeat test three times for each of three separate production batches of the indicator.
NOTE The steam exposure apparatus door can cool down between consecutive tests, thus the highest
reproducibility is obtained if the time period for the unloading-loading-start sequence is kept short and constant.

ISO/DIS 11140-3:2025(en)
Annex C
(normative)
Determination of non-uniform colour change on exposure to a
reference fault condition
C.1 Apparatus
C.1.1 Steam exposure apparatus, as specified in Annex H, fitted with an air injection system as specified
in Annex J.
C.1.2 Standard test pack, as specified in Annex I.
C.1.3 Steam supply, as specified in EN 285.
C.1.4 Thermometric recording instrument, meeting the requirements of 5.4 to record the temperature
from a minimum of six temperature sensors. The temperature sensors shall be introduced into the chamber
through the temperature-sensor entry connection and fitting.
C.2 Procedure
C.2.1 Insert thermocouples into the standard test pack in accordance with EN 285. Insert the indicator to
be tested into the centre of the standard test pack. Expose the indicator combined with the standard test
pack to a cycle of the steam exposure apparatus with the holding time and temperature pre-set to those
specified in 7.1.
C.2.2 If used (see C.2.5), locate the nozzle of the air injection system (25 ± 5) mm above, and perpendicular
to, the geometric centre of the upper surface of the test pack
C.2.3 Expose the assembled standard test pack to a cycle of the steam exposure apparatus. The operating
temperature shall be the sterilization temperature ±1 K (1 °C). Record the temperature at the centre of the
test pack and in the chamber drain of the steam exposure apparatus.
NOTE 1 As the concentration of residual, induced or injected air or non-condensable gases within the standard test
pack will not be predictably at the exact geometric centre, the additional temperature sensors in the standard test
pack are used to improve the reproducibility of the test results.
NOTE 2 The precise volume of air required to produce a reference fault condition will vary from one steam exposure
apparatus to another and with the method used to generate the reference fault condition.
C.2.4 Determine the amount of air needed to produce the reference fault condition, specified in Annex D,
within the standard test pack, using the methods given in C.2.5.
C.2.5 Use the following conditions to produce a reference fault condition (see Annex D) and when testing
the indicator.
a) Inject the volume of air into the chamber. The volume and the rate of injection should be determined by
prior trial.
b) Determine the air leak into the chamber by the method given in EN 285. The rate of air leak required
should be determined by prior trial.

ISO/DIS 11140-3:2025(en)
c) Modify the air removal stage. The reduction in the pressure range and, if necessary, in the number of
pulses in the air removal stage, should be determined by prior trial.
C.2.6 Repeat test three times for each of three separate production batches of the indicator.
C.2.7 After each test, inspect the indicator for conformance with 7.1 b).

ISO/DIS 11140-3:2025(en)
Annex D
(normative)
Reproducibility and determination of the reference fault condition in
the standard test pack
D.1 General
It is necessary to create a standard set of operating conditions that can be shown reproducibly to yield the
desired results within a standard test pack for both the no-fault (pass) condition as well as the reference
fault condition (fail condition).
Although many of the variables of the operating cycle for the steam exposure apparatus can be controlled
with great precision, the key variable, i.e. the disposition of air within the chamber and load, is the least
amenable to control, the least stable, and cannot be independently measured simultaneously.
NOTE No difficulty should be experienced in producing operating cycles which show satisfactory steam
penetration in a standard test pack. It is only when air is present that it becomes less predictable.
A statistical basis is required so that, with the minimum number of cycles and a suitable means to measure
variability, appropriate acceptance criteria can be determined:
a) for operating cycles intended to produce satisfactory steam penetration;
b) for operating cycles intended to produce a reference fault condition.
D.2 Criteria for acceptability of operating cycles
D.2.1 General
Use the conditions described in D.2.2 and D.2.3 as the limiting conditions within which the temperature
trace from the standard test pack shall lie. For each operating cycle, these criteria shall be met. In addition,
by integrating the area between the chamber reference temperature and the test pack temperature for the
hold period, it is possible to calculate the reference integrated fault (RIF) which provides a simple means of
comparing cycles [see D.2.2 j)].
D.2.2 Reference fault condition
For cycles to evaluate the ability of the indicator to detect inadequate steam penetration, the results
of thermometric monitoring of the steam exposure apparatus and the standard test pack shall meet the
following criteria as shown in Figure D.1.
a) The operating cycle, including the steam admission stage, shall meet all the criteria given in Annex C.
b) The elapsed time between the chamber attaining the set operating pressure and the chamber reference
temperature attaining the set temperature shall not exceed 5 s. In a correctly functioning steam
exposure apparatus, any difference should be due solely to the difference in response time of the
pressure and temperature sensors.
c) At the time the chamber reference temperature, T , attains the set temperature, T , the temperature
c r
measured in the standard test pack, T , shall show a temperature depression, (T − T ), of 2 K (2 °C) or
p c p
greater.
d) The temperature depression shall remain at 2 K (2 °C) or greater throughout the reference fault period.

ISO/DIS 11140-3:2025(en)
e) The test equilibration time shall be 90 s.
f) The temperature depression, (T − T ), at the beginning of the reference fault period shall be no greater
c p
than 7 K (7 °C).
g) The temperature depression, (T − T ), at the end of the reference fault period shall be no greater than
c p
4 K (4 °C).
h) The temperature depression, (T − T ), at the end of the minimum permitted equilibration time shall be
c p
no greater than 2 K (2 °C).
i) The temperature depression, (T − T ), at the end of the exposure time or 10 min, whichever is shorter,
c p
shall be no greater than 1 K (1 °C).
j)
...