SIST EN ISO 4787:2022
(Main)Laboratory glass and plastic ware - Volumetric instruments - Methods for testing of capacity and for use (ISO 4787:2021)
Laboratory glass and plastic ware - Volumetric instruments - Methods for testing of capacity and for use (ISO 4787:2021)
This document provides methods for the testing, calibration and use of volumetric instruments made
from glass and plastic in order to obtain the best accuracy in use.
NOTE Testing is the process by which the conformity of the individual volumetric instrument with the
appropriate standard is determined, resulting in the determination of its error of measurement at one or more
points.
This document is applicable to volumetric instruments with nominal capacities in the range of 100 µl
to 10 000 ml. These include single-volume pipettes (see ISO 648), graduated pipettes (see ISO 835),
burettes (see ISO 385), volumetric flasks (see ISO 1042 and ISO 5215), and graduated measuring
cylinders (see ISO 4788 and ISO 6706).
The methods are not intended for testing of volumetric instruments with capacities below 100 µl such
as micro-glassware.
This document does not deal specifically with pycnometers as specified in ISO 3507. However, the
procedures specified for the determination of volume of glassware can, for the most part, also be
followed for the determination of a pycnometer volume. For some types of pycnometers, special
handling can be necessary.
Laborgeräte aus Glas und Kunststoff - Volumenmessgeräte - Prüfverfahren und Anwendung (ISO 4787:2021)
Diese Internationale Norm legt Verfahren für die Prüfung, Kalibrierung und Anwendung von Volumen-messgeräten aus Glas und Kunststoff fest, um eine größtmögliche Genauigkeit bei der Anwendung zu erhalten.
ANMERKUNG Als Prüfung wird der Vorgang bezeichnet, anhand dessen die Konformität des einzelnen Volumen-messgeräts mit der zutreffenden Norm untersucht wird; mit dem Ziel, eine Messabweichung an einem oder mehreren Punkten zu ermitteln.
Die Internationalen Normen für einzelne Volumenmessgeräte enthalten Abschnitte mit der Definition des Nennvolumens; diese Abschnitte enthalten ausreichende Angaben zur Handhabung, womit das Nennvolumen zweifelsfrei zu bestimmen ist. Diese Internationale Norm enthält zusätzliche Angaben.
Die Prüfverfahren gelten für Volumenmessgeräte mit Nennvolumen im Bereich von 100 μl bis 10 000 ml. Sie gelten für Vollpipetten (siehe ISO 648), für Messpipetten und Verdünnungspipetten (siehe ISO 835), für Büretten (siehe ISO 385), für Messkolben (siehe ISO 1042) und für Messzylinder (siehe ISO 4788 und ISO 6706).
Die Verfahren werden nicht für die Prüfung von Volumenmessgeräten mit Nennvolumen von weniger als 100 μl empfohlen, z. B. für Mikroglasgeräte.
Diese Internationale Norm behandelt nicht ausdrücklich Pyknometer nach ISO 3507. Jedoch können die hier festgelegten Verfahren für die Volumenbestimmung zum größten Teil auch für die Kalibrierung von Pyknometern angewendet werden.
Verrerie et matériel en plastique de laboratoire - Instruments volumétriques - Méthodes d'essai de la capacité et d'utilisation (ISO 4787:2021)
Le présent document fournit des méthodes d'essai, d'étalonnage et d'utilisation des instruments volumétriques en verre et en plastique, afin d'obtenir la meilleure exactitude possible lors de l'utilisation.
NOTE L'essai est le procédé permettant d'établir la conformité de l'instrument volumétrique individuel à la norme appropriée; il se termine par la détermination de l'erreur de mesure de l'instrument en un ou plusieurs points.
Le présent document est applicable à des instruments volumétriques dont les capacités nominales sont comprises entre 100 µl et 10 000 ml. Sont concernées les pipettes à un volume (voir l'ISO 648), les pipettes graduées (voir l'ISO 835), les burettes (voir l'ISO 385), les fioles jaugées (voir l'ISO 1042 et l'ISO 5215) et les éprouvettes graduées cylindriques (voir l'ISO 4788 et l'ISO 6706).
Ces méthodes ne sont pas destinées à l'essai d'instruments volumétriques dont les capacités sont inférieures à 100 µl, comme par exemple la micro-verrerie.
Le présent document ne traite pas spécifiquement des pycnomètres, spécifiés dans l'ISO 3507. Toutefois, les modes opératoires spécifiés pour la détermination du volume de la verrerie peuvent également, en grande partie, être suivis pour la détermination du volume d’un pycnomètre. Certains types de pycnomètres peuvent nécessiter une manipulation spéciale.
Laboratorijska oprema iz stekla in plastike - Instrumenti za volumetrična merjenja - Metode za preskušanje zmogljivosti in uporaba (ISO 4787:2021)
Ta dokument podaja metode za preskušanje, umerjanje in uporabo instrumentov za volumetrična merjenja, izdelanih iz stekla in plastike, da se doseže največja natančnost pri uporabi.
OPOMBA: Preskušanje je postopek, s katerim se ugotavlja skladnost posameznega instrumenta za volumetrično merjenje z ustreznim standardom, pri čemer se določi njegova napaka pri merjenju na eni ali več točkah.
Ta dokument se uporablja za instrumente za volumetrična merjenja z nominalno kapaciteto od 100 µl do 10.000 ml. Sem spadajo pipete z eno oznako volumna (glej standard ISO 648), graduirane pipete (glej standard ISO 835), birete (glej standard ISO 385), volumetrijske steklenice (glej standarda ISO 1042 in ISO 5215) in graduirani merilni valji (glej standarda ISO 4788 in ISO 6706).
Metode niso namenjene za preskušanje instrumentov za volumetrična merjenja s kapaciteto manj kot 100 µl, kot je mikro steklovina.
Ta dokument ne obravnava posebej piknometrov, kot so opredeljeni v standardu ISO 3507. Vendar postopke za določanje prostornine steklovine je mogoče v večini uporabiti tudi za določanje prostornine piknometra. Pri nekaterih vrstah piknometrov je morda potrebno posebno ravnanje.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 4787:2022
01-februar-2022
Nadomešča:
SIST EN ISO 4787:2011
Laboratorijska oprema iz stekla in plastike - Instrumenti za volumetrična merjenja -
Metode za preskušanje zmogljivosti in uporaba (ISO 4787:2021)
Laboratory glass and plastic ware - Volumetric instruments - Methods for testing of
capacity and for use (ISO 4787:2021)
Laborgeräte aus Glas und Kunststoff - Volumenmessgeräte - Prüfverfahren und
Anwendung (ISO 4787:2021)
Verrerie et matériel en plastique de laboratoire - Instruments volumétriques - Méthodes
d'essai de la capacité et d'utilisation (ISO 4787:2021)
Ta slovenski standard je istoveten z: EN ISO 4787:2021
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
SIST EN ISO 4787:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN ISO 4787:2022
---------------------- Page: 2 ----------------------
SIST EN ISO 4787:2022
EN ISO 4787
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2021
EUROPÄISCHE NORM
ICS 17.060 Supersedes EN ISO 4787:2011
English Version
Laboratory glass and plastic ware - Volumetric
instruments - Methods for testing of capacity and for use
(ISO 4787:2021)
Verrerie et matériel en plastique de laboratoire - Laborgeräte aus Glas und Kunststoff -
Instruments volumétriques - Méthodes d'essai de la Volumenmessgeräte - Prüfverfahren und Anwendung
capacité et d'utilisation (ISO 4787:2021) (ISO 4787:2021)
This European Standard was approved by CEN on 20 November 2021.
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 NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 4787:2021 E
worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 4787:2022
EN ISO 4787:2021 (E)
Contents Page
European foreword . 3
2
---------------------- Page: 4 ----------------------
SIST EN ISO 4787:2022
EN ISO 4787:2021 (E)
European foreword
This document (EN ISO 4787:2021) 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 June 2022, and conflicting national standards shall be
withdrawn at the latest by June 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 4787:2011.
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 4787:2021 has been approved by CEN as EN ISO 4787:2021 without any modification.
3
---------------------- Page: 5 ----------------------
SIST EN ISO 4787:2022
---------------------- Page: 6 ----------------------
SIST EN ISO 4787:2022
INTERNATIONAL ISO
STANDARD 4787
Third edition
2021-11
Laboratory glass and plastic ware —
Volumetric instruments — Methods
for testing of capacity and for use
Verrerie et matériel en plastique de laboratoire — Instruments
volumétriques — Méthodes d'essai de la capacité et d'utilisation
Reference number
ISO 4787:2021(E)
© ISO 2021
---------------------- Page: 7 ----------------------
SIST EN ISO 4787:2022
ISO 4787:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 4787:2022
ISO 4787:2021(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 2
5 Volume and reference temperature . 2
5.1 Unit of volume . 2
5.2 Reference temperature . 2
6 Apparatus and calibration liquid . 2
6.1 Balance . 2
6.2 Measurement devices . 2
6.3 Calibration liquid . 3
6.4 Receiving vessel . 3
7 Factors affecting the accuracy of volumetric instruments . 3
7.1 General . 3
7.2 Temperature . 3
7.2.1 Temperature of the volumetric instrument . 3
7.2.2 Temperature of calibration liquid . 3
7.3 Cleanliness of surface . 4
7.4 Conditions of used volumetric instruments . 4
7.5 Delivery time and waiting time . 4
8 Setting the meniscus . 5
8.1 General . 5
8.2 Setting the meniscus . 5
8.2.1 Meniscus of transparent liquids . 5
8.2.2 Meniscus of opaque liquids . 7
9 Calibration procedure . 7
9.1 General . 7
9.2 Test room . 7
9.3 Filling and delivery . 7
9.3.1 Volumetric flasks and measuring cylinders . 7
9.3.2 Pipettes adjusted to deliver . 7
9.3.3 Pipettes adjusted to contain . 8
9.3.4 Burettes adjusted to deliver . 8
9.3.5 Pycnometers . . 9
9.4 Weighing . 9
9.5 Volume and uncertainty calculation . 9
10 Procedure for use .10
10.1 General . 10
10.2 Volumetric flasks (in accordance with ISO 1042 or ISO 5215) . 11
10.3 Measuring cylinders (in accordance with ISO 4788 or ISO 6706) . 11
10.4 Burettes (in accordance with ISO 385) . 11
10.5 Pipettes .12
10.5.1 Pipettes adjusted to deliver (see ISO 648 and ISO 835, or other pipettes,
e.g. plastic ones) .12
10.5.2 Pipettes adjusted to contain .12
10.6 Pycnometers .12
Annex A (informative) Cleaning of volumetric glassware .13
iii
© ISO 2021 – All rights reserved
---------------------- Page: 9 ----------------------
SIST EN ISO 4787:2022
ISO 4787:2021(E)
Annex B (informative) Cleaning of volumetric plasticware .14
Annex C (normative) Calculation formulae and tables .15
Annex D (informative) Coefficient of cubic thermal expansion .19
Annex E (informative) Uncertainty estimation and repeatability calculation .20
Bibliography .21
iv
© ISO 2021 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 4787:2022
ISO 4787:2021(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 third edition cancels and replaces the second edition (ISO 4787:2010), which has been technically
revised.
The main changes compared to the previous edition are as follows:
a) volumetric plastic ware has been included;
b) new information on meniscus adjustment of convex meniscus has been added; namely, altered
procedure “Upper edge of the graduation line is horizontally tangential to the highest point of
meniscus” as compared to older procedure “Upper edge of the graduation line is horizontally
tangential to the lowest point of the meniscus”;
c) improved figures for meniscus adjustment have been provided;
d) Table 1 has been improved;
e) new Table 2 for minimum requirements for the measurement devices has been added;
f) new test room ambient conditions have been added;
g) new information regarding repeatability and uncertainty has been added in Annex E;
h) Formula (C.1) has been changed to Formula (1).
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.
v
© ISO 2021 – All rights reserved
---------------------- Page: 11 ----------------------
SIST EN ISO 4787:2022
ISO 4787:2021(E)
Introduction
The International Standards for the individual volumetric instruments include clauses on the
specification of capacity (volume); these clauses describe the method of manipulation in sufficient detail
to determine the capacity without ambiguity. This document contains supplementary information.
vi
© ISO 2021 – All rights reserved
---------------------- Page: 12 ----------------------
SIST EN ISO 4787:2022
INTERNATIONAL STANDARD ISO 4787:2021(E)
Laboratory glass and plastic ware — Volumetric
instruments — Methods for testing of capacity and for use
1 Scope
This document provides methods for the testing, calibration and use of volumetric instruments made
from glass and plastic in order to obtain the best accuracy in use.
NOTE Testing is the process by which the conformity of the individual volumetric instrument with the
appropriate standard is determined, resulting in the determination of its error of measurement at one or more
points.
This document is applicable to volumetric instruments with nominal capacities in the range of 100 µl
to 10 000 ml. These include single-volume pipettes (see ISO 648), graduated pipettes (see ISO 835),
burettes (see ISO 385), volumetric flasks (see ISO 1042 and ISO 5215), and graduated measuring
cylinders (see ISO 4788 and ISO 6706).
The methods are not intended for testing of volumetric instruments with capacities below 100 µl such
as micro-glassware.
This document does not deal specifically with pycnometers as specified in ISO 3507. However, the
procedures specified for the determination of volume of glassware can, for the most part, also be
followed for the determination of a pycnometer volume. For some types of pycnometers, special
handling can be necessary.
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 385, Laboratory glassware — Burettes
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 835, Laboratory glassware — Graduated pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 1773, Laboratory glassware — Narrow-necked boiling flasks
ISO 3507, Laboratory glassware — Pyknometers
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 4788, Laboratory glassware — Graduated measuring cylinders
ISO 4797, Laboratory glassware — Boiling flasks with conical ground joints
1)
ISO 5215 , Laboratory plastic ware — Volumetric flasks
ISO 6706, Plastics laboratory ware — Graduated measuring cylinders
ISO 24450, Laboratory glassware — Wide-necked boiling flasks
1) Under preparation. Stage at the time of publication: ISO/DIS 5215:2021.
1
© ISO 2021 – All rights reserved
---------------------- Page: 13 ----------------------
SIST EN ISO 4787:2022
ISO 4787:2021(E)
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/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/
4 Principle
The general procedure for testing the capacity (volume) and for use is based upon a determination of
volume of water, either contained in or delivered by the volumetric instrument. This volume of water
is based upon knowledge of its mass under consideration of buoyancy and its density (gravimetric
method).
5 Volume and reference temperature
5.1 Unit of volume
3
The unit of volume shall be the millilitre (ml), which is equivalent to one cubic centimetre (cm ).
5.2 Reference temperature
The standard reference temperature, i.e. the temperature at which the volumetric instrument is
intended to contain or deliver its volume (capacity), shall be 20 °C.
When the volumetric instrument is required for use in a country which has adopted a standard
reference temperature of 27 °C (according to ISO 384), this figure shall replace 20 °C in Formula (1).
6 Apparatus and calibration liquid
6.1 Balance
The balance used for testing shall be chosen in accordance with the minimum requirements specified
in Table 1, depending on the nominal volume of the volumetric instrument under test.
Table 1 — Minimum requirements for the balance
Nominal capacity Expanded uncertainty in
Resolution Repeatability
a
(volume) use U (k = 2)
V mg mg mg
100 µl ≤ V ≤ 10 ml 0,1 0,2 0,4
10 ml < V ≤ 1 000 ml 1 2 4
V > 1 000 ml 10 10 40
a
Expanded uncertainty in use estimated according to Reference [1] (which includes applicable definitions) at the value
of the nominal volume. If uncertainty in use is not available, then the uncertainty at calibration should be taken.
6.2 Measurement devices
The minimum requirements for each relevant measurement device are specified in Table 2.
2
© ISO 2021 – All rights reserved
---------------------- Page: 14 ----------------------
SIST EN ISO 4787:2022
ISO 4787:2021(E)
Table 2 — Minimum requirements for the measurement devices
Expanded uncertainty of meas-
urement
Device Resolution
U (k = 2)
Thermometer for liquids 0,1 °C 0,2 °C
Thermometer for room air 0,1 °C 0,2 °C
Hygrometer 1 % relative humidity 5 % relative humidity
Barometer 0,1 kPa 1 kPa
Timing device 1 s Not applicable
6.3 Calibration liquid
As calibration liquid during testing, distilled or de-ionized water complying with ISO 3696, Grade 3 or
better should be used. The water temperature shall be within ± 0,5 °C of room air temperature.
6.4 Receiving vessel
The receiving vessel shall be a conical flask, manufactured from glass, e.g. in accordance with ISO 1773,
ISO 4797, or ISO 24450, if possible, with ground joint. The receiving vessel shall have a capacity adequate
to the amount of water delivered by the volumetric instrument.
7 Factors affecting the accuracy of volumetric instruments
7.1 General
The same sources of error are, naturally, inherent to calibration, testing and use. In calibration, every
attempt is made to reduce these errors to a minimum; in use, the care needed is dependent upon the
degree of accuracy required. When the greatest possible accuracy is desired, the volumetric instrument
should be used as closely as possible to the way it has been calibrated.
7.2 Temperature
7.2.1 Temperature of the volumetric instrument
The capacity of the volumetric instruments varies with change of temperature. The particular
temperature at which a volumetric instrument is intended to contain or deliver its nominal capacity is
the “reference temperature” of the instrument (see 5.2).
When performing calibrations, it is important to refer to the reference temperature in the report. For
example, if a volumetric instrument made of borosilicate glass having a coefficient of cubic thermal
−6 −1
expansion of 9,9 × 10 °C is calibrated at 20 °C but used at a temperature of 27 °C it would show an
extra error of 0,007 %. A volumetric instrument made of soda-lime glass having a coefficient of cubic
−6 −1
thermal expansion of 27 × 10 °C would show an extra error of 0,02 %, for a 7 °C temperature change.
7.2.2 Temperature of calibration liquid
The temperature of the water used for the calibration shall be measured to ± 0,1 °C, with a maximum
variation of ± 1 °C during the test. Corrections for differences in temperature, prevailing during testing
or use, from the reference temperature shall be applied in accordance with Formula (1) (see 9.5) and
Annex C. The liquid temperature should be measured in the vessel where the instruments are filled
from or directly inside the instruments, if technically possible.
3
© ISO 2021 – All rights reserved
---------------------- Page: 15 ----------------------
SIST EN ISO 4787:2022
ISO 4787:2021(E)
7.3 Cleanliness of surface
The volume contained in, or delivered by, a volumetric instrument depends on the cleanliness of the
internal surface. Lack of cleanliness of glass surface results in errors through a poorly shaped meniscus
involving two defects:
— incomplete wetting of the glass surface, i.e. the liquid surface meets the glass at an arbitrary angle
instead of forming a curve such that it meets the glass tangentially;
— a generally increased radius of curvature, due to contamination of the liquid surface reducing the
surface tension.
Volumetric instruments made of polyolefins, such as polypropylene (PP) and polymethylpentene (PMP),
or fluoroplastics, such as perfluoroalkoxy-copolymer (PFA), have water-repellent surfaces which
results in a poorly shaped convex or even flat meniscus (see 8.2).
The ascending or descending liquid meniscus shall not change shape (i.e. it shall not crinkle at its edges).
To ascertain whether a piece of apparatus is satisfactorily clean, it shall be observed during filling
and dispensing. Additionally, an experienced operator can recognize the shape of an uncontaminated
meniscus, in relation to its diameter.
Lack of cleanliness causes additional errors with volumetric instruments used for delivery due to
the film of liquid on the walls being irregularly distributed or incomplete, e.g. forming drops on the
glass surface. Furthermore, chemical residues can introduce an error in the analytical result by
contamination. Where volumetric instruments are fitted with ground stoppers, special attention shall
be pa
...
SLOVENSKI STANDARD
oSIST prEN ISO 4787:2021
01-marec-2021
Laboratorijska oprema iz stekla in plastike - Instrumenti za volumetrična merjenja -
Metode za preskušanje zmogljivosti in uporaba (ISO/DIS 4787:2021)
Laboratory glass and plastic ware - Volumetric instruments - Methods for testing of
capacity and for use (ISO/DIS 4787:2021)
Laborgeräte aus Glas und Kunststoff - Volumenmessgeräte - Prüfverfahren für Volumen
und Anwendung (ISO/DIS 4787:2021)
Verrerie et matériel en plastique de laboratoire - Instruments volumétriques - Méthodes
d'essai de la capacité et d'utilisation (ISO/DIS 4787:2021)
Ta slovenski standard je istoveten z: prEN ISO 4787
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
oSIST prEN ISO 4787:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN ISO 4787:2021
---------------------- Page: 2 ----------------------
oSIST prEN ISO 4787:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 4787
ISO/TC 48 Secretariat: DIN
Voting begins on: Voting terminates on:
2021-01-22 2021-04-16
Laboratory glass and plastic ware — Volumetric
instruments — Methods for testing of capacity and for use
ICS: 17.060; 17.060
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
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
ISO/CEN PARALLEL PROCESSING
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
Reference number
NATIONAL REGULATIONS.
ISO/DIS 4787:2021(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2021
---------------------- Page: 3 ----------------------
oSIST prEN ISO 4787:2021
ISO/DIS 4787:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 4787:2021
ISO/DIS 4787:2021(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Summary of method . 2
5 Volume and reference temperature . 2
5.1 Unit of volume . 2
5.2 Reference temperature . 2
6 Apparatus and calibration liquid . 2
7 Factors affecting the accuracy of volumetric instruments . 3
7.1 General . 3
7.2 Temperature . 3
7.2.1 Temperature of the volumetric instrument . 3
7.2.2 Temperature of calibration liquid . 3
7.3 Cleanliness of surface . 4
7.4 Conditions of used volumetric instruments . 4
7.5 Delivery time and waiting time. 4
8 Setting the meniscus . 4
8.1 General . 4
8.2 Setting the meniscus . 5
8.2.1 Meniscus of transparent liquids . 5
8.2.2 Meniscus of opaque liquids . 6
9 Calibration procedure . 6
9.1 General . 6
9.2 Test room . 7
9.3 Filling and delivery . 7
9.3.1 Volumetric flasks and measuring cylinders . . 7
9.3.2 Pipettes adjusted to deliver . 7
9.3.3 Pipettes adjusted to contain . . 8
9.3.4 Burettes adjusted to deliver . 8
9.4 Weighing . 8
9.5 Volume and uncertainty calculation . 9
10 Use .10
10.1 General .10
10.2 Volumetric flasks (see ISO 1042 or ISO 5215) . .10
10.3 Measuring cylinders (see ISO 4788 or 6706) .11
10.4 Burettes (see ISO 385) .11
10.5 Pipettes .11
Annex A (informative) Cleaning of volumetric glassware .12
Annex B (informative) Cleaning of volumetric plasticware .13
Annex C (normative) Calculation formulas and tables .14
Annex D (informative) Coefficient of cubical thermal expansion .18
Annex E (informative) Repeatability and uncertainty calculation .19
Bibliography .20
© ISO 2021 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 4787:2021
ISO/DIS 4787:2021(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, WG7-
Volumetric apparatus made of glass and plastic.
This third edition cancels and replaces the second edition (ISO 4787:2010), which has been technically
revised.
The main changes compared to the previous edition are as follows:
a) plastic ware was included;
b) new information on meniscus adjustment of convex meniscus;
c) improved figures for meniscus adjustment;
d) Table 1 was improved;
e) new Table 2 for minimum requirements for the measurement devices;
f) new test room ambient conditions;
g) new information regarding repeatability and uncertainty added in Annex E;
h) Formula (C.1) was changed to Formula (1).
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.
iv © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 4787:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 4787:2021(E)
Laboratory glass and plastic ware — Volumetric
instruments — Methods for testing of capacity and for use
1 Scope
This International Standard provides methods for the testing, calibration and use of volumetric
instruments made from glass and plastic in order to obtain the best accuracy in use.
NOTE Testing is the process by which the conformity of the individual volumetric instrument with the
appropriate standard is determined, culminating in the determination of its error of measurement at one or
more points.
The International Standards for the individual volumetric instruments include clauses on the definition
of capacity; these clauses describe the method of manipulation in sufficient detail to define the capacity
without ambiguity. This International Standard contains supplementary information.
The procedures are applicable to volumetric instruments with nominal capacities in the range of 100 µl
to 10 000 ml. These include single-volume pipettes (see ISO 648), graduated measuring pipettes and
dilution pipettes (see ISO 835), burettes (see ISO 385), volumetric flasks (see ISO 1042), and graduated
measuring cylinders (see ISO 4788 and ISO 6706).
The procedures are not recommended for testing of volumetric instruments with capacities below
100 µl such as micro-glassware.
This International Standard does not deal specifically with pycnometers as specified in ISO 3507.
However, the procedures specified below for the determination of volume of glassware can, for the
most part, also be followed for the calibration of pycnometers.
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 385, Laboratory glassware — Burettes
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 835, Laboratory glassware — Graduated pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 1773, Laboratory glassware — Narrow-necked boiling flasks
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 4788, Laboratory glassware — Graduated measuring cylinders
ISO/IEC Guide 99:2007, International vocabulary of metrology — Basic and general concepts and
associated terms (VIM)
ISO 6706, Plastics laboratory ware — Graduated measuring cylinders
ISO/IEC Guide 98:2008, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
me a s ur ement (GUM: 1995)
© ISO 2021 – All rights reserved 1
---------------------- Page: 7 ----------------------
oSIST prEN ISO 4787:2021
ISO/DIS 4787:2021(E)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC Guide 99 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Summary of method
The general procedure for testing of capacity and for use is based upon a determination of volume of
water, either contained in or delivered by the volumetric instrument. This volume of water is based
upon knowledge of its mass under consideration of buoyancy and its density (gravimetric method).
5 Volume and reference temperature
5.1 Unit of volume
3
The unit of volume shall be the millilitre (ml), which is equivalent to one cubic centimetre (cm ).
5.2 Reference temperature
The standard reference temperature, i.e. the temperature at which the volumetric instrument is
intended to contain or deliver its volume (capacity), shall be 20 °C.
When the volumetric instrument is required for use in a country which has adopted a standard
reference temperature of 27 °C (the alternative recommended in ISO 384 for tropical use), this figure
shall be substituted for 20 °C.
6 Apparatus and calibration liquid
6.1 Analytical balance or equivalent weighing device.
The balance used for testing shall be chosen according the specified minimum requirements of Table 1,
depending on the nominal volume of the volumetric instrument under test.
Table 1 — Minimum requirements for the balance
Expanded uncertainty in
Nominal capacity Readability Repeatability
a
use U (k = 2)
V mg mg mg
100 µl ≤ V ≤ 10 ml 0,1 0,2 0,4
10 ml < V ≤ 1 000 ml 1 2 4
V > 1 000 ml 10 10 40
a
Expanded uncertainty in use obtained according to EURAMET CG-18 [2] (which includes applicable definitions) at the
value of the nominal volume. If uncertainty in use is not available, then the uncertainty at calibration should be taken.
6.2 Measurement devices
The minimum requirements for each relevant measurement device are described in Table 2.
2 © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
oSIST prEN ISO 4787:2021
ISO/DIS 4787:2021(E)
Table 2 — Minimum requirements for the measurement devices
Expanded uncertainty of meas-
urement
Parameter Readability
(k = 2)
Thermometer for liquids 0,1 °C 0,2 °C
Thermometer for room air 0,1 °C 0,2 °C
Hygrometer 1 % rel. humidity 5 % rel. humidity
Barometer 0,1 kPa 1 kPa
Timing device 1 s Not applicable
6.3 Calibration liquid, distilled or deionized water complying with ISO 3696, Grade 3 should be used
for testing. The water temperature shall be within ±0,5 °C of ambient air temperature.
6.4 Receiving vessel, conical flask, if possible, with ground joint, manufactured from glass, e.g. in
accordance with ISO 1773, ISO 4797, or ISO 24450. The receiving vessel shall have a capacity adequate to
the amount of water delivered by the volumetric instrument.
7 Factors affecting the accuracy of volumetric instruments
7.1 General
The same sources of error are, naturally, inherent both in calibration and use. In the former, every
attempt is made to reduce these errors to a minimum; in the latter, the care needed is dependent
upon the degree of accuracy required. When the greatest possible accuracy is desired, the volumetric
instrument should be used as closely as possible to the way it has been calibrated.
7.2 Temperature
7.2.1 Temperature of the volumetric instrument
7.2.1.1 The capacity of the volumetric instruments varies with change of temperature. The particular
temperature at which a volumetric instrument is intended to contain or deliver its nominal capacity is
the “reference temperature” of the instrument (see 5.2).
7.2.1.2 A volumetric instrument which was calibrated at 20 °C, but used at a reference temperature of
27 °C, would show an extra error of only 0,007 % if it is made of borosilicate glass having a coefficient
−6 −1
of cubical thermal expansion of 9,9 × 10 °C and of 0,02 % if it is made of soda-lime glass having a
−6 −1.
coefficient of cubical thermal expansion of 27 × 10 °C , respectively. These errors are smaller than the
limits of error for most volumetric instruments. When performing calibrations, it is important to refer to
the reference temperature.
7.2.2 Temperature of calibration liquid
The temperature of the water used for the calibration shall be measured to ±0,1 °C, with a maximum
variation of ±1 °C during the test. Corrections for differences in temperature, prevailing during testing
or use, from the reference temperature shall be applied in accordance with Formula (1), 9.5 and
Annex C. The liquid temperature should be measured in the vessel where the instruments are filled
from or directly inside the instruments if technically possible.
© ISO 2021 – All rights reserved 3
---------------------- Page: 9 ----------------------
oSIST prEN ISO 4787:2021
ISO/DIS 4787:2021(E)
7.3 Cleanliness of surface
The volume contained in, or delivered by, of a volumetric instrument depends on the cleanliness of the
internal surface. Lack of cleanliness of glass surface results in errors through a poorly shaped meniscus
involving two defects:
— incomplete wetting of the glass surface, i.e. the liquid surface meets the glass at an arbitrary angle
instead of forming a curve such that it meets the glass tangentially;
— a generally increased radius of curvature, due to contamination of the liquid surface reducing the
surface tension.
Volumetric instruments made of polyolefins, such as Polypropylene (PP) and Polymethylpentene (PMP),
or fluoroplastics, such as Perfluoroalkoxy-Copolymer (PFA), have water-repellent surfaces which
results in a poorly shaped convex or even flat meniscus (see 8.2 and 8.3).
The ascending or descending liquid meniscus shall not change shape (i.e. it shall not crinkle at its edges).
To ascertain whether a piece of apparatus is satisfactorily clean, it shall be observed during filling
and dispensing. Additionally, an experienced operator can recognize the shape of an uncontaminated
meniscus, in relation to its diameter.
Lack of cleanliness causes additional errors with volumetric instruments used for delivery due to
the film of liquid on the walls being irregularly distributed or incomplete, e.g. forming drops on the
glass surface. Furthermore, chemical residues can introduce an error in the analytical result by
contamination. Therefore, where volumetric instruments are fitted with ground stoppers, special
attention shall be paid to cleaning the ground zone.
NOTE Small residues of acid, for example, could impair the concentration of the alkaline solution with which
the volumetric instrument is filled.
Satisfactory methods of cleaning are described in Annex A and Annex B.
7.4 Conditions of used volumetric instruments
The surface shall be free from obvious damage, the graduations and inscriptions shall be clearly
readable and especially with instruments adjusted to deliver the jet shall be free from damage and
allow an unrestricted outflow of liquid.
7.5 Delivery time and waiting time
For volumetric instruments used for delivery of a liquid, the volume delivered is always less than the
volume contained, due to the film of liquid left on the inner walls of the volumetric instrument. The
volume of this film depends on the time taken to deliver the liquid, and the volume delivered decreases
with decreasing delivery time. For example, the delivered volume of a pipette or burette will decrease
if the jet is broken (shorter delivery time) or will increase if the jet is not clean and the outflow of liquid
is restricted.
In view of the above, delivery times and waiting times have been specified in the International Standards
on volumetric instruments; these times shall be observed.
8 Setting the meniscus
8.1 General
Most volumetric instruments employ the principle of setting or reading a meniscus (the interface
between air and the liquid) against a graduation line or ring mark. Wherever practicable, the meniscus
should descend to the position of setting.
4 © ISO 2021 – All rights reserved
---------------------- Page: 10 ----------------------
oSIST prEN ISO 4787:2021
ISO/DIS 4787:2021(E)
The tubing of the volumetric instrument shall be in a vertical position. The eye of the operator shall be
in the same horizontal plane as the meniscus or the graduation line (graduation mark).
8.2 Setting the meniscus
8.2.1 Meniscus of transparent liquids
In case of a concave meniscus, the meniscus shall be set so that the plane of the upper edge of the
graduation line is horizontally tangential to the lowest point of the meniscus, the line of sight being in
the same plane (see Figure 1).
Key
1 Meniscus
2 Graduation line
3 dark coloured paper
Figure 1 — Setting of concave meniscus
In case of a convex or even flat meniscus, known for water-repellent, non-wetting surfaces of polyolefins,
such as PP and PMP, or fluoroplastics, such as PFA, the meniscus shall be set so that the plane of the
upper edge of the graduation line is horizontally tangential to the highest point of the meniscus, the line
of sight being in the same plane (see Figure 2).
Key
1 Meniscus
2 Graduation line
3 dark coloured paper
Figure 2 — Setting of convex meniscus (left) or even flat (right)
In case that an instrument showing a convex or even flat meniscus was calibrated according to the
procedure noted in the previous version of ISO 4787 (upper edge of the graduation line is horizontally
tangential to the lowest point of the meniscus) differences by setting meniscus with the procedure
© ISO 2021 – All rights reserved 5
---------------------- Page: 11 ----------------------
oSIST prEN ISO 4787:2021
ISO/DIS 4787:2021(E)
mentioned above (upper edge of the graduation line is horizontally tangential to the highest point of the
meniscus) shall be corrected. These differences can lead to very significant values with respect to the
error limit.
On volumetric instruments fitted with a Schellbach ribbon, the meniscus shall be set using the
constriction produced by the interaction between the meniscus and the Schellbach ribbon. Setting is
done when the tip of the constriction points to the graduation line (see Figure 3).
Key
1 Meniscus
2 Graduation line
3 dark coloured paper
Figure 3 — Setting of meniscus with Schellbach ribbon
The lighting should be arranged so that the meniscus appears dark and distinct in outline. For this
purpose, it should be viewed against a white background and shaded from undesirable illumination.
This can be achieved, for example, by securing a strip of black or blue paper directly below the level of
the graduation line or ring mark or by using a short section of thick black rubber tubing cut open at one
side and of such size as to clasp the tube firmly. Parallax is avoided when the graduation lines are of
sufficient length to be seen at the front and back of the volumetric instrument simultaneously.
On volumetric instruments which have graduation lines on the front only, parallax can be made
negligible when making a setting on the top edge of the line by using the black shading strip, taking
care that the top edge of this is in a horizontal plane. In this case, the eye shall be placed so that the
front and back portions of the top edge appear to be coincident.
8.2.2 Meniscus of opaque liquids
When the volumetric instrument is used with opaque wetting liquids forming a concave meniscus, the
horizontal line of sight shall be taken through the upper edge of the meniscus, and, where necessary, an
appropriate correction shall be applied.
In case of a convex or even flat meniscus, the meniscus shall be set so that the plane of the upper edge of
the graduation line is horizontally tangential to the highest point of the meniscus, the line of sight being
in the same plane, and, where necessary, an appropriate correction shall be applied.
9 Calibration procedure
9.1 General
Volumetric instruments other than disposable pipettes shall be thoroughly cleaned shortly before
calibration (see 7.3). Volumetric instruments adjusted to contain shall be dried after cleaning.
6 © ISO 2021 – All rights reserved
---------------------- Page: 12 ----------------------
oSIST prEN ISO 4787:2021
ISO/DIS 4787:2021(E)
For volumetric instruments adjusted to deliver, it is important that receiving vessels manufactured
from glass are used. Capillary effects influencing the delivery time and the delivered volume depend
considerably on the material on which the liquid runs down
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.