DRAFT INTERNATIONAL STANDARD ISO/DIS 10012

ISO/TC 176/SC 3 Secretariat: NEN

Voting begins on Voting terminates on

2001-04-02 2001-09-12
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION •    • ORGANISATION INTERNATIONALE DE NORMALISATION

Measurement control systems

(Revision of ISO 10012-1:1992 and ISO 10012-2:1997)

Systèmes de maîtrise de la mesure

ICS 03.120.10; 17.020

ISO/CEN PARALLEL ENQUIRY

The CEN Secretary-General has advised the ISO Secretary-General that this ISO/DIS covers a
subject of interest to European standardization. In accordance with subclause 5.1 of the Vienna
Agreement, consultation on this ISO/DIS has the same effect for CEN members as would a CEN
enquiry on a draft European Standard. Should this draft be accepted, a final draft, established on
the basis of comments received, will be submitted to a parallel two-month FDIS vote in ISO and formal
vote in CEN.

To expedite distribution, this document is circulated as received from the committee

secretariat. ISO Central Secretariat work of editing and text composition will be undertaken at
publication stage.
Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du
secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au
Secrétariat central de l'ISO au stade de publication.

THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE REFERRED TO
AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.

IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO WHICH
REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.

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Contents

Contents......................................................................................................................................................................iii
Foreword......................................................................................................................................................................v
Introduction ................................................................................................................................................................vi
1 Scope ..............................................................................................................................................................1
2 Normative references ....................................................................................................................................1
3 Definitions.......................................................................................................................................................1
4 General requirements....................................................................................................................................2
5 Management responsibility...........................................................................................................................2
5.1 Measurement control system .......................................................................................................................3
5.2 Customer requirements ................................................................................................................................3
5.3 Quality objectives ..........................................................................................................................................3
5.4 Management review.......................................................................................................................................3
6 Resource management .................................................................................................................................4
6.1 Human resources...........................................................................................................................................4
6.1.1 Assignment of personnel..............................................................................................................................4
6.1.2 Competence and training..............................................................................................................................4
6.2 Information resources ...................................................................................................................................4
6.2.1 Procedures .....................................................................................................................................................4
6.2.2 Software ..........................................................................................................................................................4
6.2.3 Records...........................................................................................................................................................4
6.2.4 Identification...................................................................................................................................................5
6.3 Material resources .........................................................................................................................................5
6.3.1 Measuring equipment....................................................................................................................................5
6.3.2 Storage and handling of measuring equipment .........................................................................................5
6.3.3 Environmental conditions.............................................................................................................................5
6.4 Outside suppliers...........................................................................................................................................5
7 Measurement control system realization ....................................................................................................6
7.1 Metrological confirmation process ..............................................................................................................6
7.1.1 Metrological confirmation .............................................................................................................................6
7.1.2 Confirmation intervals...................................................................................................................................6
7.1.3 Equipment characteristics ............................................................................................................................6
7.1.4 Equipment adjustment control .....................................................................................................................6
7.1.5 Confirmation process records......................................................................................................................7
7.2 Measurement process ...................................................................................................................................8
7.2.1 Process design and planning .......................................................................................................................8

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7.2.2 Process realization ........................................................................................................................................8

7.2.3 Nonconforming equipment ...........................................................................................................................9
7.2.4 Records of control of measurement processes .......................................................................................10
7.3 Measurement realization .............................................................................................................................10
7.3.1 Measurement uncertainty ...........................................................................................................................10
7.3.2 Traceability ...................................................................................................................................................11
8 Measurement control system analysis and improvement.......................................................................11
8.1 Measurement control system audit............................................................................................................11
8.2 Monitoring of measurement processes.....................................................................................................11
8.2.1 Analysis of the measurement processes ..................................................................................................12
8.2.2 Corrective action for the measurement process ......................................................................................12
8.3 Improvement.................................................................................................................................................12
Annex A (Informative) Metrological confirmation process overview ..................................................................15
Annex B (informative) Bibliography........................................................................................................................17

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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 whom 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 3.

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.

The Annexes of ISO 10012 are for information only.

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Introduction

An effective measurement control system ensures that measuring equipment and measurement processes are fit
for their intended use and is important in achieving product quality objectives. The objective of a measurement
control system is to manage the risk that measuring equipment and measurement processes could produce
incorrect results that would affect the quality of the organization’s product. The methods used for the measurement
control system range from basic equipment verification to the application of statistical techniques in the
measurement process. The organization determines the level of control needed to ensure the achievement of its
quality objectives.
References to ISO 10012 may be made:

• by a customer when specifying products required;

• by a supplier when specifying products offered;

• by legislative or regulatory bodies;

• in assessment and audit of control of measurement systems.

ISO 10012 includes both requirements and guidance for implementation of measurement control systems, and can
be useful in improving measurement activities and the quality of products. The requirements appear in normal
typeface. Guidance appears in italic typeface within a box after the appropriate requirement paragraph. Guidance
is for information only and is not to be construed as adding to, limiting, or modifying any requirement.

Organizations have the responsibility for deciding which specific measurement control system requirements are to
be applied as part of their overall quality systems. Except by agreement, ISO 10012 is not intended to add to,
subtract from, nor replace any requirements of other standards.

Following the requirements laid down in ISO 10012 will facilitate compliance with requirements for measurements
and measurement process control in other standards, for example, in the ISO 9000 and 14000 families of
standards. Interested parties may agree to use ISO 10012 as an input for satisfying measurement system
requirements in certification or registration activities. Other standards and guides exist for particular elements
affecting measurement results, for example, details of measurement methods, competence of personnel, inter-
laboratory comparisons. ISO 10012 is not intended as a substitute for the requirements of ISO 17025.
For information, an overview of metrological confirmation is given in Annex A.

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Measurement control systems

1 Scope
1.1 ISO 10012 is intended to provide generic requirements for systems managing measurement processes and
confirmation of measuring equipment used to support and demonstrate compliance with requirements. It
specifies features of a measurement control system that can be used by an organization performing
measurements as part of the overall management system.

1.2 ISO 10012 contains quality management requirements for an organization to ensure that metrological
requirements are satisfied.

2 Normative references
The following standards and documents contain provisions which, through reference in this text, constitute
provisions of ISO 10012. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards and documents indicated below. Members of IEC
and ISO maintain registers of currently valid International Standards.

ISO 3534-1:1993 Statistics – vocabulary and symbols – Part 1: Probability and general statistical terms.

ISO 9000:2000 Quality management systems – Fundamentals and vocabulary

VIM: 1993 International vocabulary of basic and general terms used in metrology. BIPM, IEC, IFCC, ISO,
IUPAC, IUPAP, OIML

GUM: 1995 Guide to the expression of uncertainty in measurement. BIPM, IEC, IFCC, ISO, IUPAC, IUPAP,
OIML

3 Definitions
For the purposes of this International Standard, the terms and definitions given in the normative references and the
following apply:

3.1
measurement control system
set of interrelated or interacting elements necessary to achieve metrological confirmation and continual control of
measurement processes.

3.2
measurement process
set of operations to determine the value of a quantity

3.3
measuring equipment
measuring instrument, software, measurement standard, reference material or auxiliary apparatus or combination
thereof necessary to realize a measurement process

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3.4
metrological characteristic (of a measuring equipment)
distinguishing feature which can influence the results of measurement

NOTE 1 Measuring equipment usually has several metrological characteristics.

NOTE 2 Metrological characteristics can be the subject of calibration.

3.5
metrological confirmation
set of operations required to ensure that measuring equipment conforms to the requirements for its intended use.
NOTE 1 Metrological confirmation generally includes calibration or verification, any necessary adjustment or repair, and
subsequent recalibration, comparison with the metrological requirements for the intended use of the equipment, as well
as any required sealing and labeling.
NOTE 2 Metrological confirmation is not achieved until and unless the fitness of the measuring equipment for the intended use
has been demonstrated and documented.

NOTE 3 The requirements for intended use include such considerations as range, resolution, maximum permissible errors, etc.
NOTE 4 Metrological confirmation requirements are usually distinct from and are not specified in product requirements.
NOTE 5 A diagram of the processes involved in metrological confirmation is given in Figure 2.
NOTE 6 For brevity in ISO 10012, this term may be referred to as “confirmation”.
3.6
metrological function
function with organizational responsibility for defining and implementing the measurement control system.

4 General requirements

The measurement control system shall ensure specified metrological requirements are satisfied.

Guidance

Metrological requirements are derived from specified requirements for the product or for the equipment to be
calibrated, verified or confirmed. These requirements are needed for both measuring equipment and measurement
processes. Requirements can be expressed as maximum permissible error, permissible uncertainty, range,
stability, resolution, environmental conditions or operator skills.

All measuring equipment within the system shall be confirmed (see 7.1). The measurement processes within the
system shall be controlled.

The organization shall specify the measurement processes which are subject to the provisions of this standard.

5 Management responsibility
The responsibilities for the metrological function shall be defined by the organization. Top management of the
organization shall ensure the availability of the necessary resources to establish and maintain the metrological
function.

Guidance

The metrological function can be distributed throughout the organization.

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5.1 Measurement control system

The management of the metrological function shall establish, document, maintain, and continually improve the
effectiveness of the measurement control system. Changes to the system shall be in accordance with the
requirements of the organization. When deciding the scope and extent of the system, the risks and consequences
of failure to comply with metrological requirements shall be taken into account.

The measurement control system consists of the metrological confirmation of measuring equipment and control of
the realization of designated measurement processes (see Figure 1).

5.2 Customer requirements

The management of the metrological function shall ensure that customer measurement needs and expectations are
determined and converted into metrological requirements. The management of the metrological function shall
ensure the measurement control system fulfils the customers’ metrological requirements. The management of the
metrological function shall be able to demonstrate compliance to customer requirements.
NOTE When determining customer measurement needs and expectations, it is important to consider obligations related to
product, including statutory and regulatory requirements (see 7.2.1).

5.3 Quality objectives

The management of the metrological function shall define and establish quality objectives for the measurement
control system. Objective performance criteria and procedures for the measurement processes, and their control,
shall be defined.

Guidance

Examples of such quality objectives at different organizational levels are:

a) no client’s product rejected due to incorrect measurements

b) no measurement process out of control without detection for more than one day

c) all confirmations completed by agreed times

d) no illegible confirmation records

e) improve technical competency of the staff

f) no measuring equipment used without prior confirmation

g) reduce the downtime for measuring equipment

5.4 Management review

Top management of the organization shall ensure the systematic review of the measurement control system at
planned intervals to ensure its continual effective implementation and satisfaction of needs. The management shall
ensure the necessary resources are available to assess the measurement control system.
The plan(s) for the management review of the measurement control system shall be documented. Based on the
results of the review, the management of the metrological function shall modify the system as necessary. The
results of all reviews and all actions taken shall be recorded.

Guidance

The input to this process of review can include the analysis as required under clause 8.

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6 Resource management

6.1 Human resources

6.1.1 Assignment of personnel

The management of the metrological function shall define and document the responsibilities of all personnel
assigned to the operation and control of the measurement control system.

Guidance

These responsibilities can be defined in organization charts, job descriptions, and work instructions or procedures.
This standard does not exclude the use of specialist personnel external to the metrological function.

6.1.2 Competence and training

The management of the metrological function shall ensure that personnel involved in the measurement control
system are competent to perform their assigned tasks. Any specialized skills required shall be documented. The
management shall ensure that training is provided to address identified needs, and that the effectiveness of the
training is evaluated and documented. Personnel shall be made aware of the extent of their responsibilities and
accountabilities, and the impact of their activities on the effectiveness of the measurement control system and
product quality.

6.2 Information resources

6.2.1 Procedures
Measurement control system procedures shall be documented and validated to the extent necessary to ensure the
proper implementation, consistency of application, and validity of measurement results.
New procedures or changes to documented procedures shall be authorized and controlled. Procedures shall be
current, available, and provided when required.

Guidance

Technical procedures can be based on published standard measurement practices, or on customers’ or equipment
manufacturers’ written instructions.

6.2.2 Software
Software used in the measurement processes and calculations of results shall be documented, identified, and
controlled to ensure suitability for continued use. Software, and any revisions to it, shall be tested and/or validated
prior to use, approved for use, and archived.

Guidance
Software can be in several forms, such as imbedded, programmable, or off-the-shelf packages. Control of software
and testing for use should be to the extent necessary to ensure proper measurement results.
Testing may include virus checking, checking of user programmed algorithms, configuration management for
complex or critical applications, or a combination thereof as necessary to achieve the required measurement result.

6.2.3 Records
Records containing information required for the operation of the measurement control system shall be established
and maintained. A documented procedure shall ensure the identification, storage, protection, retrieval, retention
time, and disposition of records.

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6.2.4 Identification
Process elements of the measurement control system shall be clearly identified, individually or collectively. There
shall be an identification of the status of confirmation of equipment. Instruments or equipment confirmed for use
only in a particular measurement process or processes shall be clearly identified or otherwise controlled to prevent
unauthorized use. Equipment not in the confirmation system shall be distinguishable from confirmed equipment.

6.3 Material resources

6.3.1 Measuring equipment

All measuring equipment necessary to satisfy specified metrological requirements shall be available and identified
in the measurement control system records. Measuring equipment shall be confirmed and used in an environment
that is controlled to the extent necessary to ensure valid measurement results. Measuring equipment used to
monitor and record the influence quantities shall be included in the measurement control system.

Guidance

Measuring equipment can be confirmed for use for particular measurement processes, and not confirmed for use
for other measurement processes because of differing metrological requirements. Metrological requirements are
derived from specified requirements for the product or the equipment to be calibrated, verified and/or confirmed.

6.3.2 Storage and handling of measuring equipment

The management of the metrological function shall establish, maintain and use documented procedures for
receiving, handling, transporting, storing and dispatching measuring equipment, in order to prevent abuse, misuse,
damage and changes in metrological characteristics. There shall be procedures for the disposition of measuring
equipment removed from the measurement control system.

6.3.3 Environmental conditions

The environmental conditions necessary for the correct operation of the measurement processes covered by the
measurement control system shall be documented.
Environmental factors affecting measurements shall be monitored and recorded. Corrections shall be recorded
and applied to measurement results, if appropriate.

Guidance

Environmental conditions affecting measurement results can include temperature, rate of change of temperature,
humidity, lighting, vibration, dust control, cleanliness, electromagnetic interference, and other factors. Equipment
manufacturers usually provide specifications giving ranges and maximum loads, and limitations of environmental
conditions, for correct use of the equipment.

6.4 Outside suppliers

The management of the metrological function shall define and document the requirements for products and
services to be provided by outside suppliers for the measurement control system. Outside suppliers shall be
evaluated and selected on the basis of their ability to meet the documented requirements. Criteria for selection,
monitoring, and evaluation shall be defined and documented and the results recorded. Records shall be maintained
of the products or services provided by outside suppliers.

Guidance

If an outside supplier is used for calibration, the supplier should be able to demonstrate technical competence to a
laboratory standard such as ISO/IEC 17025. Procured products and services may require verification to the
specified requirements.

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7 Measurement control system realization

7.1 Metrological confirmation process

7.1.1 Metrological confirmation

Metrological confirmation (see Figure 2 and Annex A) shall be designed and implemented to give assurance that
the measurements will satisfy the metrological requirements for the measurement process. For each confirmation,
the metrological characteristics of the measuring equipment shall be compared against the metrological
requirements.

Guidance

Confirmation procedures should include permissible measurement uncertainties, and/or equipment errors required
to satisfy metrological requirements.

7.1.2 Confirmation intervals

The methods used to determine or change confirmation intervals shall be described in documented procedures.
The confirmation intervals shall be regularly reviewed and adjusted when necessary to assure continuous
compliance with the specified metrological requirements.

Guidance

Data obtained from previous confirmation histories and advancing knowledge and technology can be used for this
purpose. Records obtained using statistical process control techniques for measurements can be useful in
determining whether or not to modify confirmation intervals.

7.1.3 Equipment characteristics

Information relevant to the confirmation status of measuring equipment shall be readily available to the user,
including any limitations or special requirements.
The metrological characteristics of measuring equipment shall be suitable for its intended use.

Guidance
Examples of characteristics for measuring equipment include:

— Range;
— Bias;
— Repeatability;
— Stability;
— Hysteresis;
— Drift;
— Effects of influence quantities;
— Resolution;
— Discrimination (threshold);
— Error;
— Dead band.
If the effects of the metrological characteristics are evaluated and combined as a measurement process uncertainty
(see 7.3.1), this numerical measure allows direct comparison with the requirements as a major factor toward
confirmation. Qualitative statements of the metrological characteristics in terms of, for example “required accuracy
of measuring equipment” should be avoided.

7.1.4 Equipment adjustment control

Access to adjusting devices on confirmed measuring equipment, whose setting affects the performance, shall be
sealed or otherwise safeguarded to prevent unauthorized changes. Seals or safeguards shall be designed and
located such that tampering will be detected.

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The confirmation process procedures shall include actions to be taken when seals or safeguards are found
damaged or broken.

Guidance

The requirement for sealing does not apply to adjustment devices that are intended to be set by the user without
the need for external references; for example, zero adjusters.

7.1.5 Confirmation process records

Confirmations shall be supported by records attesting to the conditions under which the results were obtained.
Each such record shall be approved, dated, and signed by an authorized person to attest to the correctness of the
results.
Records of all relevant measuring equipment covered by the confirmation process shall be maintained. These
records shall demonstrate that each item of measuring equipment satisfies the metrological requirements specified
within the confirmation process for that equipment. Calibration certificates or reports and other relevant information
(for example, records of adjustment and repair) shall be available.
The recorded information shall include, as appropriate:

a) the description and unique identification of the equipment manufacturer, type, serial number, etc.;
b) the date(s) on which the confirmation was performed and completed;
c) the result of the confirmation;
d) the assigned confirmation interval;
e) identification of the confirmation procedure;
f) the designated maximum permissible error(s);
g) the relevant environmental conditions and a statement about any corrections necessary;
h) the uncertainties involved in calibrating the equipment and their cumulative effect;
i) details of any maintenance such as adjustment, repairs or modifications carried out;
j) any limitations of use;
k) identification of the person(s) performing the confirmation;
l) identification of the person(s) responsible for the correctness of the recorded information;
m) unique identification (such as serial numbers) of any calibration certificates and other relevant documents;
n) the traceability of calibration results;
o) the requirements for the intended use;
p) the required measurement uncertainty.
q) the calibration results obtained after, and where required, before any adjustment and repair;

Guidance
Calibration results should be recorded so that the traceability of all the measurements can be demonstrated and so
that the calibration measurements can be reproduced under conditions close to the original conditions. Where a
second or third party carries out a calibration, the confirmation system should ensure that the second or third party
is competent to do this (see 6.4).
In some instances a verification result is included in the calibration report where it is stated whether the equipment
complies with (or fails to comply with) stated requirements.

The appropriate use of statistical techniques for analyzing the results of preceding calibrations, and for assessing
the results of calibrations of several similar items of measuring equipment, can assist in the estimation of
cumulative uncertainties.

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The management of the metrological function shall ensure only authorized persons are permitted to generate,
amend, issue, and delete such records.

Guidance
The records may be in manuscript, typescript, or microfilm, or in an electronic or a magnetic memory or other data
medium.
The minimum time for the retention of records is dependent on many factors including the customer’s requirements,
statutory or regulatory requirements, and manufacturer liability. Records concerned with measurement standards
may need to be retained indefinitely.

7.2 Measurement process

7.2.1 Process design and planning
The metrological requirements shall be determined based on customer, organization, and statutory and regulatory
requirements. The measurement processes designed to meet these specified requirements shall be documented
and, if necessary, agreed to with the customer.
Measurement processes necessary to demonstrate the fulfillment of product requirements shall be determined,
planned, validated, implemented, and controlled. Influence quantities affecting the fulfillment of the requirements of
the measurement process shall be identified.

Guidance

Measurement processes may be validated by comparisons to results of other validated processes, by comparisons
of results by other measurement methods, or by continuous analysis of process characteristics.

The system shall provide for the prevention of errors by ensuring the prompt detection of deficiencies and timely
corrective actions.

Guidance
The effort devoted to measurement process control should be commensurate with the importance of the
measurements to the quality of the final product of the organization. Examples of where a high degree of
measurement process control is appropriate include critical or complex measurement systems, measurements
ensuring product safety, or measurements resulting in subsequent high cost if incorrect. Minimal process control
may be adequate for simple measurements of non-critical parts. Procedures for process control can be in generic
form for similar types of measurement equipment and applications, such as the use of measurement hand tools for
measuring machined parts.
The impact of influence quantities on the measurement process should be quantified. It may be necessary to
design and carry out specific experiments or investigations to do this. When this is not possible, the data,
specifications, and warnings provided by an equipment manufacturer should be used.

7.2.2 Process realization

The performance characteristics required for the intended use of the measurement process shall be identified and
quantified, and subject to monitoring and/or control.

Guidance
Examples of characteristics include:
— measurement uncertainty;
— stability;
— maximum permissible error;
— repeatability;
— reproducibility;
— skill level of the operator.
Other characteristics may be important for some measurement processes.

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Each measurement process subject to control shall be specified, documented, and validated. The complete
specification of such a measurement process shall include identification of all relevant equipment, measurement
procedures, measurement software, conditions of use, operator capabilities, and all other factors affecting the
reliability of the measurement result. The control of measurement processes shall be carried out in accordance with
documented procedures.

Guidance
A measurement process can be limited to the use of a single measuring equipment.
A measurement process may require data correction, for example, due to environmental conditions.
In specifying the measurement processes, it may be necessary to:
a) determine what measurements are necessary to ensure the quality of the product;
b) determine the methods of measurement;
c) determine and define the equipment required to execute the measurement methods;
d) determine the skills and qualifications of the personnel performing the measurements;
e) ensure the entire measurement method(s) (equipment, operations and calculations, personnel, etc.) have been
defined;
f) ensure the personnel assigned to carry out and interpret measurements understand the defined measurement
method(s);
g) verify personnel have the required skills (evaluation and training);
h) verify the equipment satisfies the defined requirements (validation/verification);
i) verify the equipment is still capable to satisfy requirements at planned intervals (calibration and
validation/verification);
j) verify that measurements are being carried out correctly at planned intervals (statistical analysis, competency
comparisons, etc.).

7.2.3 Nonconforming equipment

Any item of confirmed measuring equipment that is suspected or known to :

a) have been damaged;
b) have been overloaded;
c) malfunction in such a way that may invalidate its intended use;
d) produce incorrect measurement results;
e) be beyond its designated confirmation interval;
f) have been mishandled;
g) have a damaged or broken seal or safeguard;

shall be removed from service by segregation or identified by prominent labelling or marking, the nonconformance
confirmed and a nonconformance report prepared. Such equipment shall not be returned to service until the
reasons for its nonconformity have been eliminated and it is again confirmed.

Each time nonconforming measuring equipment is repaired, adjusted, or modified its confirmation interval must be
reviewed.

Nonconforming measuring equipment which is not returned to its intended metrological characteristics, shall be
clearly marked or otherwise identified. Confirmation of such equipment for other uses shall ensure that the altered
status is clearly apparent and includes identification of any limitations of use.

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Guidance

If it is impractical to adjust, repair or overhaul equipment found not to be fit for its intended use, downgrading and/or
change in its intended use is an option. Downgrading should only be used with great care as it can cause confusion
between the allowable uses of apparently identical pieces of equipment. This includes limited confirmation of only
some of the ranges or functions of multiranged equipment.

If the result of a calibration prior to any adjustment or repair were such as to indicate a risk of significant error in any
of the measurements made with the equipment before the calibration, the using organization shall determine the
potential consequences and take the necessary corrective action. This can involve re-examination of product
produced using measurements involving the nonconforming measuring equipment.

7.2.4 Records of control of measurement processes

The organization shall maintain records to demonstrate compliance with the requirements of the measurement
process, including :
a) a full description of the measurement process control system implemented, including all unique elements, for
example, operators, any unique measuring equipment or check standards used and the relevant operating
conditions.

b) the relevant data obtained from the measurement process control system, including any information relevant to
the measurement uncertainty.
c) any actions taken as a result of measurement process control data;
d) the date(s) on which each measurement process control activity was carried out;
e) the identification of any relevant verification and other documents;
f) identification of the person responsible for providing the information for the records;
g) qualifications (required and achieved) of the personnel.

Guidance

Batch identification can be adequate for consumable items used in measurement process control.

The metrological function shall ensure only authorized persons are permitted to generate, amend, issue, and delete
such records.

7.3 Measurement realization

7.3.1 Measurement uncertainty

Measurement uncertainty shall be estimated for each measurement process covered by the measurement control
system (see 5.1).

Uncertainty estimations shall be recorded. The analysis of measurement uncertainties shall be completed before
the confirmation of the measuring equipment, and the validation of the measurement process. All known sources of
measurement variability shall be documented.

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Guidance

The concepts involved and the methods that can be used in combining the uncertainty components and presenting
the results are given in the “Guide to the expression of uncertainty in measurement” (GUM). Other documented
and accepted methods may be used.

It is possible that some components of uncertainty may be small compared to other components as to make their
detailed determination unjustifiable on technical or economic grounds. If so, the decision and justification should
be recorded. In all cases, the effort devoted to determining and recording uncertainties of measurements should be
commensurate with the importance of the measurements to the quality of the final product of the organization. The
recording of uncertainty determinations can take the form of “generic statements” for similar types of measuring
equipment, with only specific variations being necessary for individual measurement processes.
The uncertainty of the measurement process should take into account the uncertainty of the calibration of the
measuring equipment.

7.3.2 Traceability

The management of the metrological function shall ensure that all measurements are traceable through a national
standards laboratory to the SI units of measurement, or to natural constants whose values in terms of the SI units
are known and recommended by the General Conference of Weights and Measures.
Where traceability through a national standards laboratory is not available, or SI units are not established, a
reference standard and related calibration or comparison methods, which are clearly specified and mutually agreed
by all parties concerned, shall be applied.
Records of traceability of the measurement results shall be maintained for as long as required by the system
procedures, the customer, or by statutory and regulatory requirements.

8 Measurement control system analysis and improvement

8.1 Measurement control system audit

The organization shall carry out, or arrange to be carried out, planned audits of the measurement control system to
ensure its continuing effective implementation and compliance with requirements. Audits shall be conducted by
personnel other than those who perform the activity being audited, and the audit results shall be reported to the
organization’s management.

Plans and procedures for the audit of the measurement control system shall be documented. Based on the results
of the audits and of other relevant factors, such as feedback from customers, the organization shall review and
modify the system as necessary for improvement. The results of all audits of the measurement control system, and
all changes to the system, shall be recorded. The organization shall ensure that actions are taken without undue
delay to eliminate detected nonconformities and their causes.

Guidance

Measurement control system audits may be carried out as a part of the audits of the organization’s management
system.

8.2 Monitoring of measurement processes

The controlled measurement processes shall be monitored in accordance with documented procedures and at
established intervals. The system shall provide for the prevention of deviations from requirements by ensuring the
prompt detection of deficiencies and timely actions for their correction.

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Guidance
Failure of the measurement control system, due for example to deterioration of a check standard or change of
operator competence, may be revealed by post-process indicators such as :
— analysis of control charts;
— analysis of trend charts;
— subsequent inspections;
— interlaboratory comparisons;
— internal audit
— customer feedback.

8.2.1 Analysis of the measurement processes

For each measurement process that is subject to control, the process elements for analysis shall be identified and
limits for the elements established. The choice of elements and control limits shall be commensurate with the risk
of failure to comply with specified requirements. These elements can include the effects of operators, equipment,
ambient conditions, influence quantities, application method, etc.

Guidance
For example : for the process of measuring impedance, resistance may be chosen as an element for analysis.
The use of check standards with control charts is one method used for monitoring a measurement process. A
series of measurements of a check standard can be analyzed using a control chart or equivalent means to judge
whether or not a given measurement process is in a state of control. The use of check standards and control charts
may not identify all errors that may arise in the measurement process

Uncertainty contributions shall be accounted for in estimating the measurement uncertainty and shall be included in
the data analysis procedures. The uncertainty of the measurement results shall be taken into account when
determining if the metrological requirements have been met. The results of the analysis shall be recorded.
The results of monitoring of measurement processes and any resulting corrective actions shall be documented to
demonstrate that the measurement process has continuously complied with the documented requirements.

8.2.2 Corrective action for the measurement process

When a relevant measurement process parameter is found to exceed specified limits, or when a sequence of
checks shows an unacceptable pattern, action shall be taken to bring the measurement process back under
control, or confirm that it remains under control.
The criteria for taking corrective action shall be documented.

Guidance
Corrective actions to be taken when process performance fails to meet stated requirements can, for example,
consist of :
a) decreasing intervals between checks of one or more processes or of the equipment used in one or more
processes;
b) repairing or eliminating unstable or unreliable equipment;
c) adjusting the time span over which the measurements are made;
d) decreasing the required uncertainty for the measurement result;
e) decreasing the maximum permissible error for the measuring equipment;
f) increasing the number of influence quantities being checked;
g) upgrading the operator skill level requirement;
h) reclassification of equipment.

8.3 Improvement

The metrological function shall plan and manage the continual improvement of the measurement control system.

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Metrological Measurement
Confirmation Process

Measuring Measurement
Equipment Realization

Figure 1, Measurement Control System

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Measuring Measurement
Equipment Standard

Calibration

Technical Calibration Calibration

Comparison Certificate / Report Identification

Equipment Metrological
Confirmation Is
Complies With Yes Requirements No
Requirements? Exist? Not Possible

Yes
No

Verification /
Is Adjustment or Confirmation Confirmation
Repair Possible? Document Identification

Verification
No
Yes

Nonconformance
Adjust or Repair Report

Review
Confirmation
Interval

User Return To User

Figure 2 — Metrological Confirmation Process

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Annex A
(Informative)
Metrological confirmation process overview

A.1 Introduction
The confirmation process has two inputs, namely, the User Metrological Requirements (UMR) and the Measuring
Equipment Characteristics (MEC), and one output, namely, confirmation status of measuring equipment.

A.2 User Metrological Requirements

The User Metrological Requirements are those measurement requirements specified by the user as relevant for the
user’s production processes and therefore depend on the specifications for the variables to be measured. The
UMR include those involved in verifying the compliance of product with customer specifications, in addition to those
arising from the control of the production process and its inputs. The determination and specification of these
requirements is the responsibility of the user, though this process may be performed on behalf of the user by some
suitably qualified person. This often requires a deep knowledge of the production processes as well as metrology.
The UMR should also take into account the risk of bad measurements, and the effects of these on the organization
and the business. The UMR may be expressed in terms of maximum permissible error, operational limits, etc.
There should be enough detail to allow the operators of confirmation processes to unequivocally decide whether or
not a particular measuring equipment is capable of control, measuring, or monitoring the specified variable or
quantity according to its intended use.
Example : It is required that the pressure must be controlled to between 200 to 250 kPa in a process reactor. This
requirement must be interpreted and expressed as a UMR for the pressure measuring equipment. This
could result in a UMR that the equipment be capable of measuring a pressure range of 150 to 300 kPa,
with 2 kPa of maximum permissible error, an uncertainty of measurement of 0,3 kPa (not including the
time related effects), and with a drift not larger than 0,1 kPa per specified time period. The user
compares the UMR with the characteristics (either explicit or implicit) specified by the equipment
manufacturer and selects measuring equipment and procedures that best match the UMR. The user
may specify a particular supplier’s manometer with an accuracy class of 0,5% and a range of 0 to 400
kPa.

A.3 Measuring Equipment Characteristics

Since the MEC are often determined by calibration (or several calibrations) and/or tests, the metrological function
within the confirmation system specifies and controls all such necessary activities. The inputs for the calibration
process are the measuring equipment, a measurement standard, and a procedure stating the environmental
conditions. The calibration results must include a statement of the measurement uncertainty. This is an important
characteristic as an input when evaluating the measurement uncertainty for the measurement process when the
equipment is used. The calibration results can be documented within the confirmation system in any appropriate
method, for example as calibration certificates or calibration reports (when calibrations are outsourced), or by
records of calibration results (when performed entirely within the metrological function of the organization).
Important characteristics for measurements, for example, measurement uncertainty, are not only dependent on the
equipment but also depend on the environment, the specific procedure of measurement, and sometimes the skills
and experience of the operator. For this reason, it is very important that the whole measurement process is
considered when selecting measuring equipment to satisfy user requirements. This consideration is the
responsibility of the metrological function for the organization, though specific activities may be performed either by
the organization or by an appropriately qualified person such as an independent metrologist.

A.4 Verification and confirmation

After the calibration, the MEC are compared to the UMR before confirming the equipment for its intended use. For
example, the reported error of indication of the measuring equipment would be compared to the maximum
permissible error specified as a UMR. If the error is smaller than the maximum permissible error, then the
equipment complies with that requirement, and can be confirmed for use. Otherwise, it is necessary to take

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corrective actions. Such direct comparison of MEC and UMR is often termed verification (see ISO 9000:2000). The
confirmation system is firmly based on such verifications, but must also include detailed consideration and review
of the complete measurement process in order to give assurance of the quality of the measurements made with the
equipment in support of determining the compliance of product with the customer requirements.
Example : Following the example in A.2, let us assume that the error found by calibration is 3 kPa at 200 kPa, with
a calibration measurement uncertainty of 0,3 kPa. Therefore, the instrument does not meet the
requirement of maximum permissible error. After adjustment, the error found by calibration is 0,6 kPa
and the uncertainty in the calibration process is 0,3 kPa. The instrument now complies with the
maximum permissible error requirement and it can be confirmed for use assuming that evidence
demonstrating compliance with the drift requirement has been obtained. However, if the instrument was
submitted for reconfirmation, the user of the instrument should be informed of the results of the first
calibration since corrective actions may be required concerning product production for a period before
the instrument was taken out of use pending reconfirmation.
Whether performed by the user or by the metrology function, the results of the verification process may be
compiled into a verification document, in addition to any calibration or test certificates or reports, as part of an audit
trail within the confirmation system. The final stage in the confirmation system is the proper identification of status
of the measuring equipment, for example by labelling, marking, etc. After this, the measuring equipment can be
used for the purpose it has been confirmed.

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Annex B
(informative)
Bibliography

B.1 ISO publications

ISO 3534-2:1993 — Statistics-Vocabulary and symbols-Part 2: Statistical quality control
ISO 5725 — Accuracy (trueness and precision) of measurement methods and results :
Part 1 General principles and definitions.
Part 2 Basic methods for the determination of repeatability and reproducibility of a standard measurement
method.
Part 3 Intermediate measures of the precision of a standard measurement method
Part 4 Basic methods for the determination of the trueness of a standard measurement method.
Part 5 Alternative methods for the determination of the precision of a standard measurement method.
Part 6 Use in practice of accuracy values
ISO 9001:2000 — Quality management systems-Requirements
ISO 9004:2000 — Quality management systems-Guidelines for performance improvement
ISO 10011-1:1990 — Guidelines for auditing quality systems
ISO 14001:1996 — Environmental management systems-Specification with guidance for use
ISO 10005:1995 — Quality management-Guidelines for quality plans
ISO 10013:1995 — Guidelines for developing quality manuals
ISO/TR 10017:1999 — Guidance on statistical techniques for ISO 9001:1994
ISO/TR 13425:1995 — Guide for the selection of statistical methods in standardisation and specification
ISO/IEC 17025:1999 — General requirements for the competence of testing and calibration laboratories

B.2 OIML Publications:

1984 D 10 — Guidelines for the determination of recalibration intervals of measuring equipment used in testing
laboratories.

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