SIST EN ISO 8655-6:2022

SLOVENSKI STANDARD
01-julij-2022
Nadomešča:
SIST EN ISO 8655-6:2002
SIST EN ISO 8655-6:2002/AC:2009
Volumetrične naprave, delujoče na bat - 6. del: Gravimetrični referenčni postopek
merjenja za določanje prostornine (ISO 8655-6:2022, popravljena različica 2022-06)
Piston-operated volumetric apparatus - Part 6: Gravimetric reference measurement
procedure for the determination of volume (ISO 8655-6:2022, Corrected version 2022-
06)
Volumenmessgeräte mit Hubkolben - Teil 6: Gravimetrisches Referenzprüfverfahren zur
Bestimmung des Volumens (ISO 8655-6:2022, korrigierte Fassung 2022-06)
Appareils volumétriques à piston - Partie 6: Mode opératoire de mesure gravimétrique de
référence pour la détermination de volumes (ISO 8655-6:2022, Version corrigée 2022-
06)
Ta slovenski standard je istoveten z: EN ISO 8655-6:2022
ICS:
17.060 Merjenje prostornine, mase, Measurement of volume,
gostote, viskoznosti mass, density, viscosity
71.040.20 Laboratorijska posoda in Laboratory ware and related
aparati apparatus
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 8655-6
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2022
EUROPÄISCHE NORM
ICS 17.060 Supersedes EN ISO 8655-6:2002
English Version
Piston-operated volumetric apparatus - Part 6:
Gravimetric reference measurement procedure for the
determination of volume (ISO 8655-6:2022, Corrected
version 2022-06)
Appareils volumétriques à piston - Partie 6: Mode Volumenmessgeräte mit Hubkolben - Teil 6:
opératoire de mesure gravimétrique de référence pour Gravimetrisches Referenzprüfverfahren zur
la détermination de volumes (ISO 8655-6:2022, Bestimmung des Volumens (ISO 8655-6:2022,
Version corrigée 2022-06) korrigierte Fassung 2022-06)
This European Standard was approved by CEN on 13 February 2022.

This European Standard was corrected and reissued by the CEN-CENELEC Management Centre on 29 June 2022.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATIO N

EUROPÄISCHES KOMITEE FÜR NORMUN G

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8655-6:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 8655-6:2022) has been prepared by Technical Committee ISO/TC 48
"Laboratory equipment" in collaboration with Technical Committee CEN/TC 332 “Laboratory
equipment” the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by November 2022, and conflicting national standards
shall be withdrawn at the latest by November 2022.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 8655-6:2002, EN ISO 8655-6:2002/AC:2009.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 8655-6:2022, Corrected version 2022-06 has been approved by CEN as EN ISO 8655-
6:2022 without any modification.

INTERNATIONAL ISO
STANDARD 8655-6
Second edition
2022-04
Corrected version
2022-06
Piston-operated volumetric
apparatus —
Part 6:
Gravimetric reference measurement
procedure for the determination of
volume
Appareils volumétriques à piston —
Partie 6: Mode opératoire de mesure gravimétrique de référence pour
la détermination de volumes
Reference number
ISO 8655-6:2022(E)
ISO 8655-6:2022(E)
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 8655-6:2022(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 2
5 Test equipment .2
5.1 General . 2
5.2 Balance . 2
5.3 Liquid reservoir . 3
5.4 Weighing vessel. 3
5.5 Measuring devices . 3
6 Test liquid . 3
7 Test conditions .3
7.1 General . 3
7.2 Test room . 3
7.3 Evaporation . 4
7.4 Test cycle time . 4
8 Procedure .4
8.1 General . 4
8.1.1 Test volume . 4
8.1.2 Number of measurements . 4
8.1.3 Weighing procedure . 4
8.1.4 Test conditions during weighing procedure . 5
8.1.5 Dispensing of samples . 5
8.2 Preparation . 5
8.3 Single-channel air displacement pipettes (in accordance with ISO 8655-2) . 5
8.3.1 General . 5
8.3.2 Test cycle . 5
8.4 Multi-channel pipettes (in accordance with ISO 8655-2) . 7
8.5 Positive displacement pipettes (in accordance with ISO 8655-2) . 7
8.6 Burettes (in accordance with ISO 8655-3) . 7
8.7 Dilutors (in accordance with ISO 8655-4) . 8
8.7.1 General . 8
8.7.2 Test cycle . 8
8.8 Dispensers (in accordance with ISO 8655-5) . 9
8.9 Syringes (in accordance with ISO 8655-9) . 9
8.9.1 General . 9
8.9.2 Test cycle . 9
9 Evaluation .10
9.1 Calculation of evaporation loss . 10
9.2 Calculation of the corrected weighing value of each quantity delivered . 10
9.3 Conversion of the corrected weighing values to volume . 10
9.3.1 General . 10
9.3.2 Calculation of volume using the general formula . 10
9.3.3 Calculation of volume using the Z correction factor .12
9.3.4 Mean delivered volume.12
9.4 Systematic error of measurement . 13
9.5 Random error of measurement .13
9.6 Uncertainty of measurement .13
iii
ISO 8655-6:2022(E)
10 Reporting of results .14
Annex A (informative) Calculation of volumes from balance readings .15
Bibliography .16
iv
ISO 8655-6:2022(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 48, Laboratory equipment, in collaboration
with the European Committee for Standardization (CEN) Technical Committee CEN/TC 332, Laboratory
equipment, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna
Agreement).
This second edition cancels and replaces the first edition (ISO 8655-6:2002), which has been technically
revised. It also incorporates the Technical Corrigendum ISO 8655-6:2002/Cor .1:2008), which has been
technically revised.
The main changes are as follows:
— expanded uncertainty of the test equipment in Table 1 and 2 has been revised in conjunction with
ISO/TR 20461;
— Annex B has been deleted;
— new Clause 4 “General requirements” has been added;
[13]
— Formula (2) has been added based on ISO 4787 .
A list of all parts in the ISO 8655 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
This corrected version of ISO 8655:6:2022 incorporates the following corrections:
• Values in the key to Formula (4) are updated to include commas,
• Values in Table A.1 are updated to include commas.
v
ISO 8655-6:2022(E)
Introduction
The ISO 8655 series addresses the needs of:
— manufacturers, as a basis for quality control including, where appropriate, the issuance of
manufacturer’s declarations;
— calibration laboratories, test houses, users of the equipment and other bodies as a basis for
independent calibration, testing, verification and routine tests.
The tests specified in the ISO 8655 series are intended to be carried out by trained personnel.
vi
INTERNATIONAL STANDARD ISO 8655-6:2022(E)
Piston-operated volumetric apparatus —
Part 6:
Gravimetric reference measurement procedure for the
determination of volume
1 Scope
This document specifies a gravimetric reference measurement procedure for the determination of
volume of piston-operated volumetric apparatus (POVA). The procedure is applicable to complete
systems comprising the basic apparatus and all parts selected for use with the apparatus, disposable or
reusable, involved in the measurement by delivery (Ex) or contained (In).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods
ISO 8655-1:2022, Piston-operated volumetric apparatus — Part 1: Terminology, general requirements and
user recommendation
ISO 8655-2:2022, Piston-operated volumetric apparatus — Part 2: Pipettes
ISO 8655-3, Piston-operated volumetric apparatus — Part 3: Burettes
ISO 8655-4, Piston-operated volumetric apparatus — Part 4: Dilutors
ISO 8655-5, Piston-operated volumetric apparatus — Part 5: Dispensers
ISO 8655-9, Piston-operated volumetric apparatus — Part 9: Manually operated precision laboratory
syringes
ISO/IEC Guide 2, Standardization and related activities — General vocabulary
ISO/IEC Guide 99, International vocabulary of metrology — Basic and general concepts and associated
terms (VIM)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8655-1, ISO/IEC Guide 2 and
ISO/IEC Guide 99 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
ISO 8655-6:2022(E)
4 General requirements
When performing calibrations according to the reference measurement procedure described in
this document, all provisions and requirements of this document shall be followed or exceeded (e. g.
performing 30 instead of 10 replicates per volume). If one or more of those requirements are not
followed, conformity to this document shall not be claimed.
5 Test equipment
5.1 General
Measurements by the following equipment (balance, thermometers, hygrometer, barometer) shall be
traceable to the International System of Units (SI) and shall meet the uncertainty requirements of this
document.
NOTE An example of the calculation of the expanded uncertainty of the gravimetric reference procedure is
[10]
given in ISO/TR 20461 .
5.2 Balance
The balance used for testing shall be chosen according to the minimum requirements specified in
Table 1, depending on the nominal volume of the apparatus under test. The balance parameters are
defined so that the expanded uncertainty in use is less than one-fourth of the maximum permissible
systematic error of the apparatus.
Table 1 — Minimum requirements for balances
Nominal volume of appa- Expanded uncertainty in
a
Resolution (d) Repeatability (s)
a, b
ratus under test (V) use U (k = 2)
mg mg mg
c c, e c, e
0,001 0,006 0,012
0,5 µl ≤ V < 20 µl
d d d
0,01 0,03 0,06
20 μl ≤ V < 200 μl 0,01 0,025 0,05
200 μl ≤ V ≤ 10 ml 0,1 0,2 0,4
10 ml < V ≤ 1 000 ml 1 2 4
1 000 ml < V ≤ 2 000 ml 10 10 40
a
The repeatability and expanded uncertainty in use value, in this table, apply in the volume determination of a single
channel apparatus. When a single-channel balance is used exclusively for volume determination of multichannel pipettes
the repeatability and expanded uncertainty in use values are double the values of this table. See also Footnote d.
b
Expanded uncertainty in use can be estimated according to Reference [2] or Reference [11] at the value of the nominal
volume. Expanded uncertainty in use shall include non-corrected errors as well as possible drift and environmental
effects to balance sensitivity. Regular sensitivity adjustments are recommended to improve balance sensitivity. Expanded
uncertainty in use may be taken from the balance calibration certificate or calculated separately (see example in
ISO/TR 20461). Expanded uncertainty in use can be estimated from the expanded uncertainty of calibration by considering
additional contributions as described above, where applicable
c
Single-channel balance.
d
Multi-channel balance, only valid for multi-channel pipettes. Multi-channel balances of 0,01 mg readability may be
used to test multi-channel pipettes with nominal volumes below 20 µl only if the expanded uncertainty in use is less than
one-fourth of the maximum permissible systematic error of the apparatus.
e
For single-channel pipettes of nominal volumes of less than 2 µl, a balance with repeatability and an expanded
uncertainty better than the values in the table shall be used so that the expanded uncertainty in use is less than one-fourth
of the maximum permissible systematic error of the apparatus.
ISO 8655-6:2022(E)
5.3 Liquid reservoir
The liquid reservoir shall have sufficient capacity for all the test liquid likely to be required for the
complete series of tests.
NOTE The temperature difference between the test liquid and the room temperature can be minimized by
the use of an appropriate liquid reservoir.
5.4 Weighing vessel
The weighing vessel should be chosen for the selected test procedure according to Clause 8. Care shall
be taken regarding the evaporation loss of water during the delivery and weighing procedure.
5.5 Measuring devices
The minimum requirements for each relevant measurement device are specified in Table 2.
Table 2 — Minimum requirements for the measuring devices
Expanded uncertainty of meas-
urement
Device Resolution
(k = 2)
Thermometer for liquids 0,1 °C 0,2 °C
Thermometer for room air 0,1 °C 0,3 °C
Hygrometer 1 % relative humidity 5 % relative humidity
Barometer 0,1 kPa 1 kPa
Timing device 1 s not applicable
6 Test liquid
Use distilled or deionized water conforming to grade 3 or better as specified in ISO 3696:1987. The
water temperature shall be within ±0,5 °C of ambient air temperature (see 7.2).
7 Test conditions
7.1 General
All equipment used to test the POVA shall be operated as specified in the manufacturer’s instructions.
7.2 Test room
The test shall be carried out in a draught-free room with a stable environment. The test room shall have
a relative humidity between 45 % and 80 % and a temperature of (20 ± 3) °C with a maximum variation
of ±0,5 °C during the test. Prior to the test, the apparatus to be tested, all test equipment, and test liquid
shall have reached equilibrium within the specified conditions. The temperature variation of the test
room during this time should not be more than 0,5 °C per hour.
The environmental conditions, air temperature and air humidity, shall be within the specified limits for
the test room for at least 2 h before starting the test (minimum equilibration time) and during the test
itself.
NOTE It is unlikely that this minimum equilibration time will be less than 2 h and can be considerably longer.
When the POVA is required for use in a country which has adopted a standard reference temperature
[1]
of 27 °C (the alternative temperature recommended in ISO 384 for such use), this figure shall replace
the reference to 20 °C.
ISO 8655-6:2022(E)
7.3 Evaporation
Particularly for small tested volumes (<50 µl) errors due to evaporation of the test liquid during
weighing should be taken into consideration. Apart from the geometry of the weighing vessel, the test
cycle time (see 7.4) is important.
NOTE Especially for testing apparatus of the lowest volume possible, evaporation loss is an issue. A way to
handle evaporation loss is, for example, careful selection of the geometry of the weighing vessel.
Any measures to minimise evaporation (e.g. the use of a weighing vessel with a lid) should be considered
while the contribution to uncertainty due to evaporation should be estimated.
In order to keep the error due to evaporation as small as possible, the use of an evaporation trap may be
considered.
The error due to evaporation for the measuring series shall be determined experimentally in the
cycle (see 8.3.2) or in a separate study and corrected mathematically (see 9.1). The uncertainty of this
correction shall be considered in the measurement uncertainty.
7.4 Test cycle time
The test cycle time is the time required to complete the weighing of one delivered volume and shall be
kept to a minimum.
In the case of air-displacement pipettes, the test cycle time is the time between 8.3.2 h) and 8.3.2 r).
It is important that the test cycle time, as defined above, is regular from cycle to cycle, so that a reliable
mathematical compensation of the error due to evaporation during the measuring series can be applied.
8 Procedure
8.1 General
8.1.1 Test volume
In the case of a fixed-volume apparatus, the test volume is the nominal volume. In the case of variable-
volume (user selectable volume) POVA, at least the following three volumes shall be tested:
— nominal volume;
— 50 % of the nominal volume or the closest possible (if equidistant, use the higher value);
— the lower limit of the usable volume range or 10 % of the nominal volume (whichever is greater).
8.1.2 Number of measurements
To determine the measurement error of a POVA according to this document, ten measurements or
more for each volume to be tested shall be performed. These measurements are used to calculate the
systematic and the random error of measurement in accordance with Clause 9.
8.1.3 Weighing procedure
For apparatus designed to deliver (Ex), weighing shall always involve delivery of test liquid into the
weighing vessel. Weighing for apparatus designed to contain (In) shall always involve removal of test
liquid from the weighing vessel.
NOTE An example of contained (In) is the sample uptake step in the use of a dilutor.
...