EN ISO 11135-1:2007

SLOVENSKI STANDARD
01-oktober-2007
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SULSRPRþNH,62
Sterilization of health care products - Ethylene oxide - Part 1: Requirements for
development, validation and routine control of a sterilization process for medical devices
(ISO 11135-1:2007)
Sterilisation von Produkten für die Gesundheitsfürsorge - Ethylenoxid - Teil 1:
Anforderungen an die Entwicklung, Validierung und Lenkung der Anwendung eines
Sterilisationsverfahrens für Medizinprodukte (ISO 11135-1:2007)
Stérilisation des produits de santé - Oxyde d'éthylene - Partie 1: Exigences de
développement, de validation et contrôle de routine d'un processus de stérilisation pour
des dispositifs médicaux (ISO 11135-1:2007)
Ta slovenski standard je istoveten z: EN ISO 11135-1:2007
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.

EUROPEAN STANDARD
EN ISO 11135-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2007
ICS 11.080.01 Supersedes EN 550:1994
English Version
Sterilization of health care products - Ethylene oxide - Part 1:
Requirements for development, validation and routine control of
a sterilization process for medical devices (ISO 11135-1:2007)
Stérilisation des produits de santé - Oxyde d'éthylène - Sterilisation von Produkten für die Gesundheitsfürsorge -
Partie 1: Exigences de développement, de validation et de Ethylenoxid - Teil 1: Anforderungen an die Entwicklung,
contrôle de routine d'un processus de stérilisation pour des Validierung und Lenkung der Anwendung eines
dispositifs médicaux (ISO 11135-1:2007) Sterilisationsverfahrens für Medizinprodukte (ISO
11135:2007)
This European Standard was approved by CEN on 13 April 2007.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11135-1:2007: E
worldwide for CEN national Members.

Foreword
This document (EN ISO 11135-1:2007) has been prepared by Technical Committee ISO/TC 198
"Sterilization of health care products" in collaboration with Technical Committee CEN/TC 204
"Sterilization of medical devices", the secretariat of which is held by BSI.

This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by November 2007, and conflicting national
standards shall be withdrawn at the latest by May 2010.

This document supersedes EN 550:1994.

This document has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association, and supports essential requirements of EU
Directive(s).
For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this
document.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United
Kingdom.
Endorsement notice
The text of ISO 11135-1:2007 has been approved by CEN as EN ISO 11135-1:2007 without any
modifications.
Annex ZA
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 93/42/EEC Medical devices

This European Standard has been prepared under a mandate given to CEN by the European
Commission and the European Free Trade Association to provide a means of conforming to
Essential Requirements of the New Approach Directive 93/42/EEC Medical devices.

Once this standard is cited in the Official Journal of the European Communities under that
Directive and has been implemented as a national standard in at least one Member State,
compliance with the clauses of this standard given in Table ZA confers, within the limits of the
scope of this standard, a presumption of conformity with the corresponding Essential
Requirements of that Directive and associated EFTA regulations.

Table ZA — Correspondence between this European Standard and Directive 93/42/EEC
Medical devices
Clause(s)/Sub- Essential Essential Essential Qualifying
clause(s) of this Requirements Requirements Requirements (ERs) remarks/Notes
EN (ERs) of Directive (ERs) of Directive of Directive
90/385/EEC 93/42/EEC 98/79/EC
In part
4,5,6,7,8,9,10,11,12 7 8.3 B.2.3
In part
4,5,6,7,8,9,10,11,12 8.4 B.2.4

WARNING: Other requirements and other EU Directives may be applicable to the product(s)
falling within the scope of this standard.

INTERNATIONAL ISO
STANDARD 11135-1
First edition
2007-05-01
Sterilization of health care products —
Ethylene oxide —
Part 1:
Requirements for development, validation
and routine control of a sterilization
process for medical devices
Stérilisation des produits de santé — Oxyde d'éthylène —
Partie 1: Exigences de développement, de validation et de contrôle de
routine d'un processus de stérilisation pour des dispositifs médicaux

Reference number
ISO 11135-1:2007(E)
©
ISO 2007
ISO 11135-1:2007(E)
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ii © ISO 2007 – All rights reserved

ISO 11135-1:2007(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 2
3 Terms and definitions. 2
4 Quality management systems . 9
4.1 Documentation. 9
4.2 Management responsibility . 9
4.3 Product realization. 9
4.4 Measurement, analysis and improvement — Control of nonconforming product . 10
5 Sterilizing agent characterization . 10
5.1 Sterilizing agent . 10
5.2 Microbicidal effectiveness . 10
5.3 Material effects. 10
5.4 Environmental considerations . 10
6 Process and equipment characterization . 10
6.1 Process characterization . 10
6.2 Equipment characterization. 11
7 Product definition . 12
7.1 General. 12
7.2 Product safety and performance. 12
7.3 Microbiological quality. 12
7.4 Documentation. 13
8 Process definition. 13
9 Validation. 14
9.1 Installation qualification. 14
9.2 Operational qualification. 14
9.3 Performance qualification. 14
9.4 Varying load configurations . 16
9.5 Review and approval of validation. 16
10 Routine monitoring and control . 18
11 Product release from sterilization. 19
12 Maintaining process effectiveness . 19
12.1 General. 19
12.2 Maintenance of equipment . 19
12.3 Requalification . 19
12.4 Assessment of change. 20
Annex A (normative) Determination of lethal rate of the sterilization process — Biological
indicator/bioburden approach. 21
Annex B (normative) Conservative determination of lethal rate of the sterilization process —
Overkill approach. 23
Annex C (informative) General guidance. 25
Bibliography . 41
ISO 11135-1:2007(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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.
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.
ISO 11135-1 was prepared by Technical Committee ISO/TC 198, Sterilization of health care products.
ISO 11135 consists of the following parts, under the general title Sterilization of health care products —
Ethylene oxide:
⎯ Part 1: Requirements for development, validation and routine control of a sterilization process for medical
devices
⎯ Part 2: Guidance on the application of ISO 11135-1
For the purposes of this part of ISO 11135 the CEN annex regarding fulfilment of European Council Directives
will be removed at publication stage.
iv © ISO 2007 – All rights reserved

ISO 11135-1:2007(E)
Introduction
A sterile medical device is one that is free of viable microorganisms. International Standards that specify
requirements for validation and routine control of sterilization processes, require, when it is necessary to
supply a sterile medical device, that adventitious microbiological contamination of a medical device prior to
sterilization be minimized. Even so, medical devices produced under standard manufacturing conditions in
accordance with the requirements for quality management systems (see for example ISO 13485) may, prior to
sterilization, have microorganisms on them, albeit in low numbers. Such medical devices are non-sterile. The
purpose of sterilization is to inactivate the microbiological contaminants and thereby transform the non-sterile
medical devices into sterile ones.
The kinetics of inactivation of a pure culture of microorganisms by physical and/or chemical agents used to
sterilize medical devices can generally best be described by an exponential relationship between the numbers
of microorganisms surviving and the extent of treatment with the ethylene oxide; inevitably this means that
there is always a finite probability that a microorganism may survive regardless of the extent of treatment
applied. For a given treatment, the probability of survival is determined by the number and resistance of
microorganisms and by the environment in which the organisms exist during treatment. It follows that the
sterility of any one medical device in a population subjected to sterilization processing cannot be guaranteed
and the sterility of a processed population is defined in terms of the probability of there being a viable
microorganism present on a medical device.
This part of ISO 11135 describes requirements that, if met, will provide an ethylene oxide sterilization process
intended to sterilize medical devices, which has appropriate microbicidal activity. Furthermore, compliance
with the requirements ensures that this activity is both reliable and reproducible so that it can be predicted,
with reasonable confidence, that there is a low level of probability of there being a viable microorganism
present on product after sterilization. Specification of this probability is a matter for regulatory authorities and
may vary from country to country (see for example EN 556-1 and ANSI/AAMI ST67).
Generic requirements of the quality management systems for design and development, production, installation
and servicing are given in ISO 9001 and particular requirements for quality management systems for medical
device production are given in ISO 13485. The standards for quality management systems recognise that, for
certain processes used in manufacturing or reprocessing, the effectiveness of the process cannot be fully
verified by subsequent inspection and testing of the product. Sterilization is an example of such a process. For
this reason, sterilization processes are validated for use, the performance of the sterilization process
monitored routinely and the equipment maintained.
Exposure to a properly validated, accurately controlled sterilization process is not the only factor associated
with the provision of reliable assurance that the product is sterile and, in this regard, suitable for its intended
use. Attention is therefore given to a number of considerations including:
a) the microbiological status of incoming raw materials and/or components;
b) the validation and routine control of any cleaning and disinfection procedures used on the product;
c) the control of the environment in which the product is manufactured or reprocessed, assembled and
packaged;
d) the control of equipment and processes;
e) the control of personnel and their hygiene;
f) the manner and materials in which the product is packaged;
g) the conditions under which product is stored.
ISO 11135-1:2007(E)
The type of contamination on a product to be sterilized varies and this impacts upon the effectiveness of a
sterilization process. Products that have been used in a health care setting and are being presented for
resterilization in accordance with the manufacturer's instructions (see ISO 17664) should be regarded as a
special case. There is the potential for such products to possess a wide range of contaminating
microorganisms and residual inorganic and/or organic contamination in spite of the application of a cleaning
process. Hence, it is important to pay particular attention to the validation and control of the cleaning and
disinfection processes used during reprocessing.
The requirements are the normative parts of this part of ISO 11135 with which compliance is claimed. The
guidance given in the informative annexes is not normative and is not provided as a checklist for auditors. The
guidance provides explanations and methods that are regarded as being suitable means for complying with
the requirements. Methods other than those given in the guidance may be used if they are effective in
achieving compliance with the requirements of this part of ISO 11135.
The development, validation and routine control of a sterilization process comprises a number of discrete but
interrelated activities; e.g. calibration, maintenance, product definition, process definition, installation
qualification, operational qualification and performance qualification. While the activities required by this part
of ISO 11135 have been grouped together and are presented in a particular order, this part of ISO 11135 does
not require that the activities be performed in the order in which they are presented. The activities required are
not necessarily sequential, as the programme of development and validation may be iterative. It is possible
that performing these different activities will involve a number of separate individuals and/or organizations,
each of whom undertakes one or more of these activities. This part of ISO 11135 does not specify the
particular individuals or organizations to carry out the activities.
When determining the suitability of ethylene oxide (EO) for sterilization of medical devices, it is important that
patient safety is addressed by minimizing exposure to residual EO, ethylene chlorohydrin (ECH) and ethylene
glycol (EG) during normal product use (see ISO 10993-7).
vi © ISO 2007 – All rights reserved

INTERNATIONAL STANDARD ISO 11135-1:2007(E)

Sterilization of health care products — Ethylene oxide —
Part 1:
Requirements for development, validation and routine control
of a sterilization process for medical devices
1 Scope
This part of ISO 11135 specifies requirements for the development, validation and routine control of an
ethylene oxide sterilization process for medical devices.
NOTE 1 Although the scope of this part of ISO 11135 is limited to medical devices, it specifies requirements and
provides guidance that may be applicable to other health care products.
Sterilization processes validated and controlled in accordance with the requirements of this part of ISO 11135
are not assumed to be effective in inactivating the causative agents of spongiform encephalopathies such as
scrapie, bovine spongiform encephalopathy and Creutzfeld Jacob disease. Specific recommendations have
been produced in particular countries for the processing of materials potentially contaminated with these
agents.
NOTE 2 See for example ISO 22442-1, ISO 22442-2 and ISO 22442-3.
This part of ISO 11135 does not detail a specified requirement for designating a medical device as sterile.
NOTE 3 Attention is drawn to national or regional requirements for designating medical devices as “sterile”. See for
example EN 556-1 or ANSI/AAMI ST67.
This part of ISO 11135 does not specify a quality management system for the control of all stages of
production of medical devices.
NOTE 4 The effective implementation of defined and documented procedures is necessary for the development,
validation and routine control of a sterilization process for medical devices. Such procedures are commonly considered to
be elements of a quality management system. It is not a requirement of this part of ISO 11135 to have a complete quality
management system during manufacture or reprocessing, but the elements of a quality management system that are the
minimum necessary to control the sterilization process are normatively referenced at appropriate places in the text (see in
particular Clause 4). National and/or regional regulations for the provision of medical devices might require implementation
of a complete quality management system and the assessment of that system by a third party.
This part of ISO 11135 does not specify requirements for occupational safety associated with the design and
operation of ethylene oxide sterilization facilities.
NOTE 5 For further information on safety, see examples in the Bibliography. National or regional regulations may also
exist.
NOTE 6 Ethylene oxide is toxic, flammable and explosive. Attention is drawn to the possible existence in some
countries of regulations giving safety requirements for handling ethylene oxide and for premises in which it is used.
This part of ISO 11135 does not cover sterilization by injecting ethylene oxide or mixtures containing ethylene
oxide directly into individual product packages, or continuous sterilization processes.
ISO 11135-1:2007(E)
This part of ISO 11135 does not cover analytical methods for determining levels of residual ethylene oxide
and/or its reaction products.
NOTE 7 For further information see ISO 10993-7.
NOTE 8 Attention is drawn to the possible existence of regulations specifying limits for the level of ethylene oxide
residues present on or in medical devices and products.
2 Normative references
The following referenced documents are indispensable for the application 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 10012, Measurement management systems — Requirements for measurement processes and measuring
equipment
ISO 10993-1, Biological evaluation of medical devices — Part 1: Evaluation and testing
ISO 10993-7, Biological evaluation of medical devices — Part 7: Ethylene oxide sterilization residuals
ISO 11138-1:2006, Sterilization of health care products — Biological indicators — Part 1: General
requirements
ISO 11138-2:2006, Sterilization of health care products — Biological indicators — Part 2: Biological indicators
for ethylene oxide sterilization processes
ISO 11140-1, Sterilization of health care products — Chemical indicators — Part 1: General requirements
ISO 11737-1, Sterilization of medical devices — Microbiological methods — Part 1: Determination of a population
of microorganisms on products
ISO 11737-2, Sterilization of medical devices — Microbiological methods — Part 2: Tests of sterility performed in
the validation of a sterilization process
ISO 13485:2003, Medical devices — Quality management systems — Requirements for regulatory purposes
ISO 14161, Sterilization of health care products — Biological indicators — Guidance for the selection, use and
interpretation of results
ISO 14937:2000, Sterilization of health care products — General requirements for characterization of a
sterilizing agent and the development, validation and routine control of a sterilization process for medical
devices
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
aeration
part of the sterilization process during which ethylene oxide and/or its reaction products desorb from the
medical device until predetermined levels are reached
NOTE This may be performed within the sterilizer and/or in a separate chamber or room.
2 © ISO 2007 – All rights reserved

ISO 11135-1:2007(E)
3.2
aeration area
either a chamber or a room in which aeration occurs
3.3
bioburden
population of viable microorganisms on or in the product and/or sterile barrier system
[ISO/TS 11139:2006, definition 2.2]
3.4
biological indicator
test system containing viable microorganisms providing a defined resistance to a specified sterilization
process
[ISO/TS 11139:2006, definition 2.3]
3.5
calibration
set of operations that establish, under specified conditions, the relationship between values of a quantity
indicated by a measuring instrument or measuring system, or values represented by a material measure or a
reference material, and the corresponding values realized by standards
[VIM:1993, definition 6.11]
3.6
chemical indicator
test system that reveals a change in one or more predefined process variable(s) based on a chemical or
physical change resulting from exposure to a process
[ISO/TS 11139:2006, definition 2.6]
3.7
conditioning
treatment of product within the sterilization cycle, but prior to ethylene oxide admission, to attain a
predetermined temperature and relative humidity
NOTE This part of the sterilization cycle can be carried out either at atmospheric pressure or under vacuum.
See 3.25, preconditioning.
3.8
D value
D value
time or radiation dose required to achieve inactivation of 90 % of a population of the test microorganism under
stated conditions
[ISO/TS 11139:2006, definition 2.11]
NOTE For the purposes of this part of ISO 11135, the D value refers to exposure time.
3.9
development
act of elaborating a specification
[ISO/TS 11139:2006, definition 2.13]
ISO 11135-1:2007(E)
3.10
establish
determine by theoretical evaluation and confirm by experimentation
[ISO/TS 11139:2006, definition 2.17]
3.11
ethylene oxide injection time
duration of the stage beginning with the first introduction of ethylene oxide into the chamber and ending when
addition of ethylene oxide gas or the ethylene oxide gas mixture ceases
3.12
exposure time
period for which the process parameters are maintained within their specified tolerances
[ISO/TS 11139:2006, definition 2.18]
NOTE For the purposes of this part of ISO 11135, it is the period of the sterilization cycle between the end of the
ethylene oxide injection time and the initiation of ethylene oxide removal.
3.13
fault
one or more of the process parameters lying outside of its/their specified tolerance(s)
[ISO/TS 11139:2006, definition 2.19]
3.14
flushing
procedure by which the ethylene oxide is removed from the load and chamber by either
a) multiple alternate admissions of filtered air or inert gas and evacuations of the chamber or
b) continuous passage of filtered air or inert gas through the load and chamber
3.15
fractional cycle
process in which the exposure time is reduced compared to that specified in the sterilization process
3.16
half cycle
sterilization cycle in which the exposure time is reduced by 50 % compared with the sterilization process
3.17
health care product
medical device(s) including in vitro diagnostic medical device(s), or medicinal product(s), including
biopharmaceuticals
[ISO/TS 11139:2006, definition 2.20]
3.18
installation qualification
IQ
process of obtaining and documenting evidence that equipment has been provided and installed in
accordance with its specification
[ISO/TS 11139:2006, definition 2.22]
4 © ISO 2007 – All rights reserved

ISO 11135-1:2007(E)
3.19
medical device
instrument, apparatus, implement, machine, appliance, implant, in vitro reagent or calibrator, software,
material or related article, intended by the manufacturer to be used, alone or in combination, for human beings
for one or more of the specific purpose(s) of
⎯ diagnosis, prevention, monitoring, treatment or alleviation of disease,
⎯ diagnosis, monitoring, treatment, alleviation of or compensation for an injury,
⎯ investigation, replacement or modification or support of the anatomy or of a physiological process,
⎯ control of conception,
⎯ disinfection of medical devices,
⎯ providing information for medical purposes by means of in vitro examination of specimens derived from
the human body
and which does not achieve its principal intended action in or on the human body by pharmacological,
immunological or metabolic means, but which may be assisted in its function by such means
[ISO 13485:2003, definition 3.7]
NOTE This definition from ISO 13485:2003 was developed by the Global Harmonization Task Force (GHTF 2002).
3.20
microorganism
an entity of microscopic size, encompassing bacteria, fungi, protozoa and viruses
NOTE A specific standard might not require demonstration of the effectiveness of the sterilization process in
inactivating all types of microorganisms identified in the definition above for validation and/or routine control of the
sterilization process.
[ISO/TS 11139:2006, definition 2.26]
3.21
operational qualification
OQ
process of obtaining and documenting evidence that installed equipment operates within predetermined limits
when used in accordance with its operational procedures
[ISO/TS 11139:2006, definition 2.27]
3.22
overkill
sterilization process that is demonstrated as delivering at least a 12 Spore Log Reduction (SLR) to a biological
indicator having a resistance equal to or greater than the product bioburden
3.23
parametric release
declaration that product is sterile, based on records demonstrating that the process parameters were delivered
within specified tolerances
[ISO/TS 11139:2006, definition 2.29]
NOTE This method of process release does not include the use of biological indicators.
ISO 11135-1:2007(E)
3.24
performance qualification
PQ
process of obtaining and documenting evidence that the equipment, as installed and operated in accordance
with operational procedures, consistently performs in accordance with predetermined criteria and thereby
yields product meeting its specification
[ISO/TS 11139:2006, definition 2.30]
3.25
preconditioning
treatment of product, prior to the sterilization cycle, in a room or chamber to attain specified limits for
temperature and relative humidity
3.26
process challenge device
PCD
item designed to constitute a defined resistance to the sterilization process and used to assess performance
of the process
[ISO/TS 11139:2006, definition 2.33]
3.27
process parameter
specified value for a process variable
NOTE The specification for a sterilization process includes the process parameters and their tolerances.
[ISO/TS 11139:2006, definition 2.34]
3.28
process variable
condition within a sterilization process, whose changes alter microbicidal effectiveness
EXAMPLE Time, temperature, pressure, concentration and humidity.
[ISO/TS 11139:2006, definition 2.35]
3.29
product
result of a process
[ISO 9000:2005, definition 3.4.2]
NOTE For the purposes of sterilization standards, product is tangible and can be raw material(s), intermediate(s),
sub-assembly(ies) and health care products.
3.30
product load volume
defined space within the usable chamber volume occupied by product
3.31
recognized culture collection
depository authority under the Budapest Treaty on The International Recognition of the Deposit of
Microorganisms for the Purpose of Patent and Regulation
[ISO/TS 11139:2006, definition 2.38]
3.32
reference microorganism
microbial strain obtained from a recognized culture collection
[ISO/TS 11139:2006, definition 2.39]
6 © ISO 2007 – All rights reserved

ISO 11135-1:2007(E)
3.33
requalification
repetition of part of validation for the purpose of confirming the continued acceptability of a specified process
[ISO/TS 11139:2006, definition 2.40]
3.34
services
supplies from an external source, needed for the correct function of equipment
EXAMPLE Electricity, water, compressed air, drainage.
[ISO/TS 11139:2006, definition 2.41]
3.35
specify
stipulate in detail within an approved document
[ISO/TS 11139:2006, definition 2.42]
3.36
Spore Log Reduction
SLR
factor, expressed as the logarithm to base 10, describing the reduction in the number of spores on a biological
indicator produced by exposure to specified conditions
NOTE SLR can be calculated as the log of the initial population minus the log of the final population of the biological
indicator. See below:
SLR = log N − log N
0 u
where
N is the final population of the biological indicator;
u
N is the initial population of the biological indicator.
If there are no survivors, the true SLR cannot be calculated. If one positive or surviving organism is assumed, the SLR is
reported as “greater than” log N .
3.37
sterile
free from viable microorganisms
[ISO/TS 11139:2006, definition 2.43]
3.38
sterility
state of being free from viable microorganisms
NOTE In practice, no such absolute statement regarding the absence of microorganisms can be proven
See 3.40, sterilization.
[ISO/TS 11139:2006, definition 2.45]
ISO 11135-1:2007(E)
3.39
sterility assurance level
SAL
probability of a single viable microorganism occurring on an item after sterilization
−6 −3
NOTE The term SAL takes a quantitative value, generally 10 or 10 . When applying this quantitative value to
−6 −3
assurance of sterility, an SAL of 10 has a lower value but provides a greater assurance of sterility than an SAL of 10 .
[ISO/TS 11139:2006, definition 2.46]
3.40
sterilization
validated process used to render product free from viable microorganisms
NOTE In a sterilization process, the nature of microbial inactivation is described as exponential and, thus, the survival
of a microorganism on an individual item can be expressed in terms of probability. While this probability can be reduced to
a very low number, it can never be reduced to zero.
See 3.39, sterility assurance level.
[ISO/TS 11139:2006, definition 2.47]
3.41
sterilization cycle
treatment in a sealed chamber comprising air removal, conditioning (if used), injection of ethylene oxide,
exposure to ethylene oxide, removal of ethylene oxide and flushing (if used), and air/inert gas admission
3.42
sterilization load
product to be, or that has been, sterilized together using a given sterilization process
[ISO/TS 11139:2006, definition 2.48]
3.43
sterilization process
series of actions or operations needed to achieve the specified requirements for sterility
[ISO/TS 11139:2006, definition 2.49]
NOTE This series of actions or operations includes pretreatment (if necessary), exposure to the ethylene oxide under
defined conditions and any necessary post-treatment required for the removal of ethylene oxide and its by-products. It
does not include any cleaning, disinfection or packaging operations that precede the sterilization process.
3.44
sterilizing agent
physical or chemical entity, or combination of entities, having sufficient microbicidal activity to achieve sterility
under defined conditions
[ISO/TS 11139:2006, definition 2.50]
NOTE With respect to this part of ISO 11135, the sterilizing agent is ethylene oxide or a mixture of ethylene oxide
and a diluent.
3.45
survivor curve
graphical representation of the inactivation of a population of microorganisms with increasing exposure to a
microbicidal agent under stated conditions
[ISO/TS 11139:2006, definition 2.51]
8 © ISO 2007 – All rights reserved

ISO 11135-1:2007(E)
3.46
test of sterility
technical operation performed as part of development, validation or requalification to determine the presence
or absence of viable microorganisms on product or portions thereof
[ISO/TS 11139:2006, definition 2.53]
3.47
usable chamber volume
defined space within the sterilizer chamber, which is not restricted by fixed or mobile parts and which is
available to accept the sterilization load
EXAMPLE The available space on a pallet of defined dimensions.
NOTE The volume allowed for circulation inside the chamber is not included as usable space.
3.48
validation
documented procedure for obtaining, recording and interpreting the results required to establish that a process
will consistently yield product complying with predetermined specifications
[ISO/TS 11139:2006, definition 2.55]
4 Quality management systems
4.1 Documentation
4.1.1 Procedures for development, validation, routine control and product release from sterilization shall be
specified.
4.1.2 Documents and records required by this part of ISO 11135 shall be reviewed and approved by
designated personnel (see 4.2.1). Documents and records shall be controlled in accordance with the
applicable clauses of ISO 13485.
4.2 Management responsibility
4.2.1 The responsibility and authority for implementing and meeting the requirements described in this part
of ISO 11135 shall be specified. Responsibility shall be assigned to competent personnel in accordance with
the applicable clauses of ISO 13485.
4.2.2 If the requirements of this part of ISO 11135 are undertaken by organizations with separate quality
management systems, the responsibilities and authority of each party shall be specified.
4.3 Product realization
4.3.1 Procedures for purchasing shall be specified. These procedures shall comply with the applicable
clauses of ISO 13485.
4.3.2 Procedures for identification and traceability of product shall be specified. These procedures shall
comply with the applicable clauses of ISO 13485.
4.3.3 A system complying with the applicable clauses of ISO 13485 or ISO 10012 shall be specified for the
calibration of all equipment, including instrumentation for test purposes, used in meeting the requirements of
this part of ISO 11135.
ISO 11135-1:2007(E)
4.4 Measurement, analysis and improvement — Control of nonconforming product
Procedures for control of product designated as nonconforming and for correction, corrective action and
preventive action shall be specified. These procedures shall comply with the applicable clauses of ISO 13485.
5 Sterilizing agent characterization
5.1 Sterilizing agent
The composition, storage conditions and shelf life for the sterilizing agent shall be specified.
NOTE With respect to this part of ISO 11135, the sterilizing agent is ethylene oxide or a mixture of ethylene oxide
and a diluent.
5.2 Microbicidal effectiveness
Microbicidal effectiveness data shall be developed if it is proposed to use the ethylene oxide outside of the
range of compositions that are widely recognized or if a novel diluent is to be used.
NOTE The inactivation of microorganisms by ethylene oxide has been comprehensively documented in the literature.
This literature provides a knowledge of the manner in which the process variables affect microbial inactivation. Reference
to these general studies on microbial inactivation is not required by this part of ISO 11135.
5.3 Material effects
The effects of ethylene oxide on a wide variety of materials used to manufacture medical devices have been
comprehensively documented and such documentation is of value to those designing and developing medical
devices that are to be sterilized by ethylene oxide. This part of ISO 11135 does not require the perfor
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