SIST EN ISO 4259:2006
(Main)Petroleum products - Determination and application of precision data in relation to methods of test (ISO 4259:2006)
Petroleum products - Determination and application of precision data in relation to methods of test (ISO 4259:2006)
This International Standard covers the calculation of precision estimates and their application to specifications. In particular, it contains definitions of relevant statistical terms (Clause 3), the procedures to be adopted in the planning of an inter-laboratory test programme to determine the precision of a test method (Clause 4), the method of calculating the precision from the results of such a programme (Clauses 5 and 6), and the procedure to be followed in the interpretation of laboratory results in relation both to precision of the test methods and to the limits laid down in specifications (Clauses 7 to 10 ). The procedures in this International Standard have been designed specifically for petroleum and petroleum related products , which are normally homogeneous. However, the procedures described in this International Standard can also be applied to other types of homogeneous products. Careful investigations are necessary before applying this International Standard to products for which the assumption of homogeneity can be questioned.
Mineralölerzeugnisse - Bestimmung und Anwendung der Werte für die Präzision von Prüfverfahren (ISO 4259:2006)
Diese Internationale Norm umfasst die Berechnung von Schätzwerten für die Präzision sowie deren Anwendung auf Spezifikationen. Insbesondere enthält sie Definitionen für wichtige statistische Ausdrücke (siehe Abschnitt 3), die zu treffenden Maßnahmen für die Planung von Ringversuchsprogrammen für die Bestimmung der Präzision eines Prüfverfahrens (siehe Abschnitt 4), die Methodik zur Berechnung der Präzision aus den Ergebnissen von derartigen Programmen (siehe Abschnitte 5 und 6) und das anzuwendende Vorgehen für die Interpretation der Ergebnisse von einzelnen Laboratorien sowohl im Hinblick auf die Präzision des Prüfverfahrens als auch im Hinblick auf die Grenzwerte, die in Spezifikationen genannt werden (siehe Abschnitte 7 bis 10).
Es wird ausdrücklich darauf hingewiesen, dass die Verfahren in dieser Internationalen Norm zur Anwendung für Mineralölerzeugnisse und verwandte Produkte entwickelt worden sind, die im Allgemeinen homogene Produkte sind. Bevor die Anwendung dieser Internationalen Norm auf andere Erzeugnisse, bei denen die Ausnahme der Homogenität hinterfragt werden kann, ausgeweitet wird, sollten sorgfältige Untersuchungen hinsichtlich der Anwendbarkeit erwogen werden. Trotzdem sollte beachtet werden, dass die in dieser Internationalen Norm beschriebenen Verfahren auch auf andere Typen von homogenen Erzeugnissen angewendet werden können.
Produits pétroliers - Détermination et application des valeurs de fidélité relatives aux méthodes d'essai (ISO 4259:2006)
L'ISO 4259:2006 traite du calcul des estimations de fidélité et de leur application aux spécifications. En particulier, elle contient les définitions des termes statistiques concernés, les procédures à suivre dans l'organisation d'un programme d'essai interlaboratoires destiné à déterminer la fidélité d'une méthode d'essai, la méthode de calcul de la fidélité à partir des résultats d'un tel programme et la procédure à suivre dans l'interprétation des résultats de laboratoire, à la lumière de la fidélité des méthodes de test et des limites fixées dans les spécifications.
Les procédures de l'ISO 4259:2006 ont été conçues spécifiquement pour les produits pétroliers et leurs produits connexes, qui sont normalement homogènes. Cependant on reconnaît que les procédures décrites dans l'ISO 4259:2006 peuvent aussi s'appliquer à d'autres types de produits homogènes. Des contrôles attentifs s'avèrent nécessaires avant d'appliquer l'ISO 4259:2006 à des produits pour lesquels la présomption d'homogénéité peut être mise en question.
Naftni proizvodi - Določanje in uporaba stopenj natančnosti pri preskusnih metodah (ISO 4259:2006)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 4259:2006
01-november-2006
1DGRPHãþD
SIST EN ISO 4259:1998
1DIWQLSURL]YRGL'RORþDQMHLQXSRUDEDVWRSHQMQDWDQþQRVWLSULSUHVNXVQLK
PHWRGDK ,62
Petroleum products - Determination and application of precision data in relation to
methods of test (ISO 4259:2006)
Mineralölerzeugnisse - Bestimmung und Anwendung der Werte für die Präzision von
Prüfverfahren (ISO 4259:2006)
Produits pétroliers - Détermination et application des valeurs de fidélité relatives aux
méthodes d'essai (ISO 4259:2006)
Ta slovenski standard je istoveten z: EN ISO 4259:2006
ICS:
75.080 Naftni proizvodi na splošno Petroleum products in
general
SIST EN ISO 4259:2006 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN ISO 4259:2006
---------------------- Page: 2 ----------------------
SIST EN ISO 4259:2006
EUROPEAN STANDARD
EN ISO 4259
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2006
ICS 75.080 Supersedes EN ISO 4259:1995
English Version
Petroleum products - Determination and application of precision
data in relation to methods of test (ISO 4259:2006)
Produits pétroliers - Détermination et application des Mineralölerzeugnisse - Bestimmung und Anwendung der
valeurs de fidélité relatives aux méthodes d'essai (ISO Werte für die Präzision von Prüfverfahren (ISO 4259:2006)
4259:2006)
This European Standard was approved by CEN on 1 July 2006.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, 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
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 4259:2006: E
worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 4259:2006
EN ISO 4259:2006 (E)
Foreword
This document (EN ISO 4259:2006) has been prepared by Technical Committee ISO/TC 28
"Petroleum products and lubricants" in collaboration with Technical Committee CEN/TC 19
"Gaseous and liquid fuels, lubricants and related products of petroleum, synthetic and biological
origin", the secretariat of which is held by NEN.
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 February 2007, and conflicting national
standards shall be withdrawn at the latest by February 2007.
This document supersedes EN ISO 4259:1995.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
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 4259:2006 has been approved by CEN as EN ISO 4259:2006 without any
modifications.
2
---------------------- Page: 4 ----------------------
SIST EN ISO 4259:2006
INTERNATIONAL ISO
STANDARD 4259
Third edition
2006-08-01
Petroleum products — Determination and
application of precision data in relation to
methods of test
Produits pétroliers — Détermination et application des valeurs de
fidélité relatives aux méthodes d'essai
Reference number
ISO 4259:2006(E)
©
ISO 2006
---------------------- Page: 5 ----------------------
SIST EN ISO 4259:2006
ISO 4259:2006(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2006
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2006 – All rights reserved
---------------------- Page: 6 ----------------------
SIST EN ISO 4259:2006
ISO 4259:2006(E)
Contents Page
Foreword. v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Stages in the planning of an inter-laboratory test programme for the determination of the
precision of a test method . 4
4.1 General. 4
4.2 Preparing a draft method of test . 5
4.3 Planning a pilot programme with at least two laboratories. 5
4.4 Planning the inter-laboratory programme. 5
4.5 Executing the inter-laboratory programme.5
5 Inspection of inter-laboratory results for uniformity and for outliers . 6
5.1 General. 6
5.2 Transformation of data. 7
5.3 Tests for outliers. 8
5.4 Rejection of complete data from a sample . 11
5.5 Estimating missing or rejected values . 12
5.6 Rejection test for outlying laboratories. 13
5.7 Confirmation of selected transformation .14
6 Analysis of variance, calculation and expression of precision estimates . 14
6.1 General. 14
6.2 Analysis of variance . 14
6.3 Expectation of mean squares and calculation of precision estimates . 17
6.4 Expression of precision estimates of a method of test. 20
7 Significance of repeatability (r) and reproducibility (R). 21
7.1 General. 21
7.2 Repeatability, r . 21
7.3 Reproducibility, R.22
8 Specifications. 24
8.1 Aim of specifications. 24
8.2 Construction of specifications limits in relation to precision. 24
9 Quality control against specifications. 25
9.1 General. 25
9.2 Testing margin at the supplier . 25
9.3 Testing margin at the recipient . 25
10 Dispute procedure . 25
Annex A (normative) Determination of number of samples required. 28
Annex B (informative) Derivation of equation for calculating the number of samples required . 30
Annex C (normative) Notation and tests. 31
Annex D (normative) Example results of test for determination of bromine number and statistical
tables. 36
Annex E (normative) Types of dependence and corresponding transformations. 45
Annex F (normative) Weighted linear regression analysis. 49
© ISO 2006 – All rights reserved iii
---------------------- Page: 7 ----------------------
SIST EN ISO 4259:2006
ISO 4259:2006(E)
Annex G (normative) Rules for rounding off results . 56
Annex H (informative) Explanation of equations given in Clause 7 . 57
Annex I (informative) Specifications that relate to a specified degree of criticality. 59
Bibliography . 62
iv © ISO 2006 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 4259:2006
ISO 4259:2006(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 4259 was prepared by Technical Committee ISO/TC 28, Petroleum products and lubricants.
This third edition cancels and replaces the second edition (ISO 4259:1992), Clauses 1, 5, 7 C.7, E.2 and F.3
and subclauses 4.2, 5.2, 6.3.2, 6.3.3.1, 6.3.3.3, 6.4, 8.2, 10.2, 10.4 and 10.5, which have been technically
revised. It also incorporates the Technical Corrigendum ISO 4259:1992/Cor.1:1993.
© ISO 2006 – All rights reserved v
---------------------- Page: 9 ----------------------
SIST EN ISO 4259:2006
ISO 4259:2006(E)
Introduction
For purposes of quality control and to check compliance with specifications, the properties of commercial
petroleum products are assessed by standard laboratory test methods. Two or more measurements of the
same property of a specific sample by any given test method do not usually give exactly the same result. It is,
therefore, necessary to take proper account of this fact, by arriving at statistically-based estimates of the
precision for a method, i.e. an objective measure of the degree of agreement expected between two or more
results obtained in specified circumstances.
[11]
ISO 4259 makes reference to ISO 3534-2 , which gives a different definition of true value (see 3.26).
ISO 4259 also refers to ISO 5725-2. The latter is required in particular and unusual circumstances (see 5.2)
for the purpose of estimating precision.
vi © ISO 2006 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 4259:2006
INTERNATIONAL STANDARD ISO 4259:2006(E)
Petroleum products — Determination and application of
precision data in relation to methods of test
1 Scope
This International Standard covers the calculation of precision estimates and their application to specifications.
In particular, it contains definitions of relevant statistical terms (Clause 3), the procedures to be adopted in the
planning of an inter-laboratory test programme to determine the precision of a test method (Clause 4), the
method of calculating the precision from the results of such a programme (Clauses 5 and 6), and the
procedure to be followed in the interpretation of laboratory results in relation both to precision of the test
methods and to the limits laid down in specifications (Clauses 7 to 10).
The procedures in this International Standard have been designed specifically for petroleum and petroleum-
related products, which are normally homogeneous. However, the procedures described in this International
Standard can also be applied to other types of homogeneous products. Careful investigations are necessary
before applying this International Standard to products for which the assumption of homogeneity can be
questioned.
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 5725-2:1994, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic
method for the determination of repeatability and reproducibility of a standard measurement method
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
analysis of variance
technique that enables the total variance of a method to be broken down into its component factors
3.2
between-laboratory variance
element of the total variance attributable to the difference between the mean values of different laboratories
NOTE 1 When results obtained by more than one laboratory are compared, the scatter is usually wider than when the
same number of tests are carried out by a single laboratory, and there is some variation between means obtained by
different laboratories. These give rise to the between-laboratory variance which is that component of the overall variance
due to the difference in the mean values obtained by different laboratories.
NOTE 2 There is a corresponding definition for between-operator variance.
NOTE 3 The term “between-laboratory” is often shortened to “laboratory” when used to qualify representative
parameters of the dispersion of the population of results, for example as “laboratory variance”.
© ISO 2006 – All rights reserved 1
---------------------- Page: 11 ----------------------
SIST EN ISO 4259:2006
ISO 4259:2006(E)
3.3
bias
difference between the true value (related to the method of test) and the known value, where this is available
NOTE For a definition of “true value” and “known value,” see 3.26 and 3.8, respectively.
3.4
blind coding
assignment of a different number to each sample so that no other identification or information on any sample
is given to the operator
3.5
check sample
sample taken at the place where the product is exchanged, i.e. where the responsibility for the product quality
passes from the supplier to the recipient
3.6
degrees of freedom
divisor used in the calculation of variance; one less than the number of independent results
NOTE The definition applies strictly only in the simplest cases. Complete definitions are beyond the scope of this
International Standard.
3.7
determination
process of carrying out the series of operations specified in the test method, whereby a single value is
obtained
3.8
known value
actual quantitative value implied by the preparation of the sample
NOTE The known value does not always exist, for example for empirical tests such as flash point.
3.9
mean
arithmetic mean
sum of the results divided by their number for a given set of results
3.10
mean square
sum of squares divided by the degrees of freedom
3.11
normal distribution
probability distribution of a continuous random variable, x, such that, if x is any real number, the probability
density is
2
⎡⎤
11 x − µ
⎛⎞
⎢⎥
fx=−exp ,−∞
()
⎜⎟
2 σ
σ 2π⎢⎥⎝⎠
⎣⎦
NOTE µ is the true value and σ is the standard deviation of the normal distribution (σ > 0).
3.12
operator
person who normally and regularly carries out a particular test
2 © ISO 2006 – All rights reserved
---------------------- Page: 12 ----------------------
SIST EN ISO 4259:2006
ISO 4259:2006(E)
3.13
outlier
result far enough in magnitude from other results to be considered not a part of the set
3.14
precision
closeness of agreement between the results obtained by applying the experimental procedure several times
on identical materials and under prescribed conditions
NOTE The smaller the random part of the experimental error, the more precise is the procedure.
3.15
random error
chance variation encountered in all test work despite the closest control of variables
3.16
recipient
any individual or organization who receives or accepts the product delivered by the supplier
3.17
repeatability
〈qualitatively〉 closeness of agreement between independent results obtained in the normal and correct
operation of the same method on identical test material, in a short interval of time, and under the same test
conditions (same operator, same apparatus, same laboratory)
NOTE The representative parameters of the dispersion of the population that can be associated with the results are
qualified by the term “repeatability”, for example, repeatability standard deviation or repeatability variance. It is important
that the term “repeatability” not be confused with the terms “between repeats” or “repeats” when used in this way (see
3.19). Repeatability refers to the state of minimum random variability of results. The period of time during which repeated
results are to be obtained should therefore be short enough to exclude time-dependent errors, for example, environmental
and calibration errors.
3.18
repeatability
〈quantitatively〉 value equal to or below which the absolute difference between two single test results obtained
in the conditions specified that can be expected to lie with a probability of 95 %
NOTE For the details of the conditions specified, see 3.17.
3.19
replication
execution of a test method more than once so as to improve precision and to obtain a better estimation of
testing error
NOTE Replication should be distinguished from repetition in that the former implies that repeated experiments are
carried out at one place and, as far as possible, within one period of time. The representative parameters of the dispersion
of the population that can be associated with repeated experiments are qualified by the term “between repeats”, or in
shortened form “repeats”, for example, “repeats standard deviation”.
3.20
reproducibility
〈qualitatively〉 closeness of agreement between individual results obtained in the normal and correct operation
of the same method on identical test material but under different test conditions (different operators, different
apparatus and different laboratories)
NOTE The representative parameters of the dispersion of the population that can be associated with the results are
qualified by the term “reproducibility”, for example, reproducibility standard deviation or reproducibility variance.
© ISO 2006 – All rights reserved 3
---------------------- Page: 13 ----------------------
SIST EN ISO 4259:2006
ISO 4259:2006(E)
3.21
reproducibility
〈quantitatively〉 value equal to or below which the absolute difference between two single test results on
identical material obtained by operators in different laboratories, using the standardized test method, may be
expected to lie with a probability of 95 %
3.22
result
final value obtained by following the complete set of instructions in the test method; it may be obtained from a
single determination or from several determinations depending on the instructions in the method
NOTE It is assumed that the result is rounded off according to the procedure specified in Annex G.
3.23
standard deviation
measure of the dispersion of a series of results around their mean, equal to the positive square root of the
variance and estimated by the positive square root of the mean square
3.24
sum of squares
sum of squares of the differences between a series of results and their mean
3.25
supplier
any individual or organization responsible for the quality of a product just before it is taken over by the
recipient
3.26
true value
for practical purposes, the value towards which the average of single results obtained by n laboratories tends,
as n tends towards infinity
NOTE 1 Such a true value is associated with the particular method of test.
[11]
NOTE 2 A different and idealized definition is given in ISO 3534-2 .
3.27
variance
mean of the squares of the deviation of a random variable from its mean, estimated by the mean square
4 Stages in the planning of an inter-laboratory test programme for the
determination of the precision of a test method
4.1 General
The stages in planning an inter-laboratory test programme are as follows:
a) preparing a draft method of test;
b) planning a pilot programme with at least two laboratories;
c) planning the inter-laboratory programme;
d) executing the inter-laboratory programme.
The four stages are described in turn in 4.2 to 4.5.
4 © ISO 2006 – All rights reserved
---------------------- Page: 14 ----------------------
SIST EN ISO 4259:2006
ISO 4259:2006(E)
4.2 Preparing a draft method of test
This shall contain all the necessary details for carrying out the test and reporting the results. Any condition that
could alter the results shall be specified.
A clause on precision is included in the draft method of the test at this stage only as a heading. It is
recommended that the lower limit of the scope of the test method is not less than the region of the lowest
value tested in the inter-laboratory programme, and is at least 2R greater than the lowest achievable result
(see 8.2), where R is the reproducibility estimate. Similarly, it is recommended that the upper limit of the scope
of a test method is not greater than the region of the highest value tested in the inter-laboratory programme,
and is at least 2R less than the highest achievable result.
4.3 Planning a pilot programme with at least two laboratories
A pilot programme is necessary for the following reasons:
a) to verify the details in the operation of the test;
b) to find out how well operators can follow the instructions of the method;
c) to check the precautions regarding samples;
d) to estimate approximately the precision of the test.
At least two samples are required, covering the range of results to which the test method is intended to apply;
however, at least twelve laboratory/sample combinations shall be included. Each sample is tested twice by
each laboratory under repeatability conditions. If any omissions or inaccuracies in the draft test method are
revealed, they shall now be corrected. The results shall be analysed for bias and precision; if either is
considered to be too large, then alterations to the test method shall be considered.
4.4 Planning the inter-laboratory programme
There shall be at least five participating laboratories, but it is preferable that there are more in order to reduce
the number of samples required.
The number of samples shall be sufficient to cover the range of the property measured at approximately
equidistant intervals and to give reliability to the precision estimates. If precision is found to vary with the level
of results in the pilot programme, then at least five samples shall be used in the inter-laboratory programme. In
any case, it is necessary to obtain at least 30 degrees of freedom in both repeatability and reproducibility. For
repeatability, this means obtaining a total of at least 30 pairs of results in the programme.
For reproducibility, Table A.1 gives the minimum number of samples required in terms of L, P and Q, where L
is the number of participating laboratories, and P and Q are the ratios of variance component estimates
obtained from the pilot programme. Specifically, P is the ratio of the interaction component to the repeats
component and Q is the ratio of the laboratories component to the repeats component. Annex B gives the
derivation of the equation used. If Q is much larger than P, then 30 degrees of freedom cannot be achieved;
the blank entries in Table A.1 correspond to, or an approach to, this situation (i.e. when more than 20 samples
are required). For these cases, there is likely to be a significant bias between laboratories.
4.5 Executing the inter-laboratory programme
One person shall be responsible for the entire programme, from the distribution of the texts of the test method
and samples to the final appraisal of the results. He shall be familiar with the test method, but shall not
personally take part in the tests.
The text of the test method shall be distributed to all the laboratories in time to allow any queries to be raised
before the tests begin. If any laboratory wants to practice the method in advance, this shall be carried out with
samples other than those used in the programme.
© ISO 2006 – All rights reserved 5
---------------------- Page: 15 ----------------------
SIST EN ISO 4259:2006
ISO 4259:2006(E)
The samples shall be accumulated, subdivided and distributed by the organizer, who shall also keep a reserve
of each sample for emergencies. It is most importan
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.