ISO/TR 13881:2000

TECHNICAL ISO/TR
REPORT 13881
First edition
2000-04-15
Petroleum and natural gas industries —
Classification and conformity assessment
of products, processes and services
Industries du pétrole et du gaz naturel — Classification et évaluation
de la conformité des produits, procédés et services
Reference number
©
ISO 2000
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ii © ISO 2000 – All rights reserved

Contents Page
Foreword.iv
Introduction.v
1 Scope .1
2 References.1
3 Terms and definitions .1
4 Classification principles .2
5 Classification method based on calculation.3
6 Classification method based on judgement .4
7 Limitations.6
8 Conformity assessment systems.6
9 System A.8
10 System B.10
11 System C.12
12 System D.13
13 System E.14
Annex A Classification method based on judgement.15
Annex B Frequently asked questions.18
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
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Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
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In exceptional circumstances, when a technical committee has collected data of a different kind from that which is
normally published as an International Standard ("state of the art", for example), it may decide by a simple majority
vote of its participating members to publish a Technical Report. A Technical Report is entirely informative in nature
and does not have to be reviewed until the data it provides are considered to be no longer valid or useful.
Attention is drawn to the possibility that some of the elements of this Technical Report may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TR 13881 was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore structures for
petroleum and natural gas industries.
iv © ISO 2000 – All rights reserved

Introduction
When a user/purchaser wishes to procure a product, process or service, the user/purchaser may produce a
functional specification (see ISO 13879). If so, the manufacturer/supplier provides a technical specification (see
ISO 13880) as the basis for manufacturing or execution. The user/purchaser decides on the extent to which it is
necessary to determine, directly or indirectly, that relevant requirements are fulfilled and states this in the contract
with the manufacturer/supplier.
This document describes:
� two methodologies which enable the required degree of assurance to be determined by classification, which in
turn dictates the conformity assessment system;
� a set of five conformity assessment systems which when applied can give an increasing level of confidence
that the product, process or service conforms to stated requirements.
TECHNICAL REPORT ISO/TR 13881:2000(E)
Petroleum and natural gas industries — Classification and
conformity assessment of products, processes and services
1 Scope
This Technical Report describes:
� two classification methods (one based on calculated risk, the other on judgement of risk) which may be used to
determine the appropriate conformity assessment system for products, processes and services;
� a set of five conformity assessment systems from which the most suitable is chosen when conformity
assessment of products, processes and services is required.
NOTE Alternative classification models may be used provided their results are consistent with the conformity assessment
systems to be applied.
2 References
ISO/IEC Guide 2:1996, Standardization and related activities — General vocabulary.
ISO/IEC Guide 22:1996, General criteria for supplier's declaration of conformity.
ISO/IEC Guide 28:1982, General rules for a model third-party certification system for products.
1)
ISO 9001:— , Quality management systems — Requirements.
ISO 9002:1994, Quality systems — Model for quality assurance in production, installation and servicing.
ISO 9003:1994, Quality systems — Model for quality assurance in final inspection and test.
ISO 13879:1999, Petroleum and natural gas industries — Content and drafting of a functional specification.
ISO 13880:1999, Petroleum and natural gas industries — Content and drafting of a technical specification.
3 Terms and definitions
For the purposes of this Technical Report, the terms and definitions of conformity-assessment-related terms given
in ISO/IEC Guide 2 apply, with the exception of the terms defined below.
3.1
class
number assigned to a product, process or service, associated with the risk of its failure during use due to design or
manufacturing, process or service errors, that indicates the appropriate conformity assessment system to be
adopted
1) To be published. (Revision of ISO 9001:1994)
NOTE The classification of a product, process or service does not take into consideration failure due to misuse or incorrect
maintenance of the product, process or service.
3.2
probability of failure
frequency of occurrence of a product, process or service failure happening within one year divided by the total
number of the particular products, processes or services in operation during the same year
3.3
consequence of failure
results of the failure of the product, process or service
NOTE In the petroleum and natural gas industries, the most commonly used measure of consequence is financial cost. This
implies that the intangible aspects of the results following a failure, such as community acceptance, be translated to financial
cost. The cost for failure can comprise cost for restoring the environment (i.e. damage to the environment), deferred or loss of
production, reduction in efficiency, health and safety-related cost, etc.
3.4
risk of failure
probability multiplied by consequence
3.5
design review
formal, documented, comprehensive and systematic examination of a design to evaluate the design requirements
and the capabilities of the design to meet these requirements
NOTE 1 In the context of the document, the acceptance criteria for the design review are defined in the functional and
technical specifications (see ISO 13879 and ISO 13880).
NOTE 2 A service is also designed and can be reviewed in the same manner.
3.6
witness point
point in the chain of activities, defined in the quality or inspection plan agreed upon, to be witnessed by the
conformity assessment body if deemed necessary
3.7
hold point
point, defined in an appropriate document, beyond which an activity should not proceed without the approval of a
designated organization or authority
NOTE The approval to proceed beyond a hold point is usually given in written form, but it may be given by any other agreed
system of authorization.
4 Classification principles
For the purposes of this Technical Report, the following classification principles apply.
� CLASS should be determined taking full account of the total life of the product, process or service, starting with
its functional specification and ending with its decommissioning/demobilization.
� CLASS should take full account of the health, safety and environmental requirements valid for the countries in
which the product, process or service is created, used and/or decommissioned/demobilized.
� CLASS, when established according to clause 5 or clause 6, should be determined using verifiable
parameters.
In this Technical Report, five classes are defined, from 1 to 5, of which CLASS 1 represents the highest risk of
failure and CLASS 5 represents the lowest risk of failure.
The relationship between the classes and the conformity assessment systems is defined in Table 1.
2 © ISO 2000 – All rights reserved

CLASS only has a meaning and/or significance in combination with one of the conformity assessment systems
defined.
Table 1 — Class and conformity assessment system relationship
CLASS 1 System A
CLASS 2 System B
CLASS 3 System C
CLASS 4 System D
CLASS 5 System E
Clause 5 and clause 6 provide two different methods of CLASS determination.
5 Classification method based on calculation
5.1 General
This method can be used when specific data on costs and probabilities are available. Two sub-models are
presented here. When combined, they provide a full model for classification. The sub-models are based on the
assumption that cost can be allocated to the level of certainty that the product, process or service will fulfil its
intended purpose without failure. Other models may be used but are not described within this Technical Report.
NOTE The classification models are used by the user/purchaser of a product, process or service to calculate and thereafter
indicate which CLASS number is required to obtain the appropriate conformity assessment. The CLASS is related to the risk of
failure during use of a product, process and/or service.
5.2 Explanation of the factors used in the sub-models
The sub-models are built on the following premises:
� every activity bears risks which can be translated into cost;
� the models are applicable to the design and manufacture as well as the operational life of the product, process
or service.
The risks are connected with failures whereby the operational cost during the life is determined by in situ
maintenance, periodic inspection, required level of spare parts, etc.
NOTE The risk of failure can be reduced by, for example, more frequent inspections or supervisory actions, a thorough
maintenance process, a better controlled manufacturing/service process, etc.
5.3 Risk-related sub-model
T =(p � c )+(p � c )+(p � c ) [1]
r 0 0 1 1 2 2
where
T is the total risk, in monetary terms;
r
p is the probability of failure of the product, process or service during use, due to design;
c is the consequence of design-related failure;
p is the probability of failure of the product, process or service during use, due to manufacturing of product
or execution of services/processes;
...