EN ISO 7278-2:2022/A1:2026

• Status: Published
• Publication Date: 09-Jun-2026
• ICS: 75.180.30 - Volumetric equipment and measurements
• Technical Committee: CEN/TC 19 - Petroleum products, lubricants and related products
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 10-Jun-2026
• Completion Date: 10-Jun-2026
• Ref Project: SIST EN ISO 7278-2:2023/A1:2026 - Petroleum measurement systems - Part 2: Pipe prover design, calibration and operation - Amendment 1 (ISO 7278-2:2022/Amd 1:2026)

• Consolidated By: ISO 7278-2:2022/Amd 1:2026 - Petroleum measurement systems — Part 2: Pipe prover design, calibration and operation — Amendment 1
• Effective Date: 12-Feb-2026
• Amends: EN ISO 7278-2:2022 - Petroleum measurement systems - Part 2: Pipe prover design, calibration and operation (ISO 7278-2:2022)
• Effective Date: 30-Apr-2025

EN ISO 7278-2:2022/A1:2026 is a CEN amendment to the European standard for petroleum measurement systems, part 2 on pipe prover design, calibration and operation. It updates the rules for sphere inspection and sizing, adds leak checking before calibration, and requires temporary calibration modifications to be recorded. The document is intended for people who design, operate, inspect, or calibrate pipe provers.

What does EN ISO 7278-2:2022/A1:2026 specify?

EN ISO 7278-2:2022/A1:2026 specifies amendments to EN ISO 7278-2:2022 for pipe prover sphere handling and calibration practice. It focuses on how a sphere is checked, measured, and reported before and during prover calibration.

The amendment is organized around changes to clause 6.5.2, a new clause 6.5.4, an added paragraph in 11.2, and a new item in Annex H. In practice, that means the document updates the steps used to confirm that a prover sphere is the right size, in good condition, and suitable for the operating fluid and conditions.

What are the key requirements of EN ISO 7278-2:2022/A1:2026?

Sphere inspection and sizing

EN ISO 7278-2:2022/A1:2026 requires new spheres and spheres removed from a prover to be inspected in the same way. The sphere should be checked for bulges, flats, cuts, abrasions, wear, softening, and expiry date where relevant.

The practical point is that visual condition matters as much as measured size. A sphere that looks acceptable by diameter alone can still be unfit for service if the surface is damaged or degraded.

Measurement methods for sphere diameter

EN ISO 7278-2:2022/A1:2026 allows three usual measurement approaches: an outside micrometre or calliper, slip rings, or a purpose-made diameter or circumference tape. The tape measurement is made with the tape vertical around the sphere equator, and circumference can be converted to diameter.

This matters because the measurement tool has to match the precision needed for the prover. The method must be calibrated and periodically verified so the measured diameter is reliable enough for the sphere size being set.

Multiple measurements and ovality

EN ISO 7278-2:2022/A1:2026 calls for measurement across a minimum of two perpendicular diameters, with one measurement across the filling valve(s). The reported diameter is the smallest measured diameter, and the difference between the largest and smallest measured diameters is used to judge ovality.

In practice, this tells the user whether the sphere is still acceptably round. A sphere that is too oval can seal poorly, wear unevenly, or give unstable prover operation.

Fit, oversize, and compatibility

EN ISO 7278-2:2022/A1:2026 says the sphere manufacturer should be given the prover inside diameter and the expected inflation oversize. The sphere should also match the fluid and the operating conditions so that the material remains compatible.

This is important when ordering a replacement sphere. The wrong size or material can create leakage, pressure loss, or early deterioration.

Inflation control and operating behavior

EN ISO 7278-2:2022/A1:2026 notes that sphere inflation is part of prover design, but it can be changed if operating experience or product changes justify it. It also warns that underinflation can cause leakage, while overinflation can increase pressure loss, judder, and poor switch actuation.

That means the inflation setting is not just a setup detail. It affects how smoothly the prover runs and whether it switches and seals correctly.

Checks before calibration

EN ISO 7278-2:2022/A1:2026 adds that the system should be checked for leakage before calibration starts. Where relevant, the four-way valve operation and leakage should be checked, or a seal leakage test should be performed for a piston prover.

This helps confirm that the calibration is being done on a sound system. It also supports safe removal and inspection of a sphere displacer before measurement.

Calibration reporting

EN ISO 7278-2:2022/A1:2026 requires the prover to be in good operational condition during calibration, and any temporary modifications used to complete the work should be recorded in the calibration report as observations.

For users, that means calibration results should be interpreted together with the conditions under which they were obtained. Temporary fixes such as capping a leaking drain should not be hidden from the report.

What terms does EN ISO 7278-2:2022/A1:2026 use?

• Pipe prover - the prover type covered by the standard, used in petroleum measurement systems to support calibration and operation checks.
• Sphere - the inflatable displacer used in the prover, whose size and condition are checked before use.
• Sphere displacer - the sphere when treated as the moving element that is withdrawn, inspected, and measured.
• Four-way valve - a valve whose operation and leakage may need to be checked before calibration.
• Piston prover - a prover type mentioned in the calibration leak-check guidance, with a seal leakage test option.
• Ovality - the difference between the largest and smallest measured sphere diameters, used to judge whether the sphere is acceptably round.
• Schrader valve - the inflation valve mentioned for over-inflating, venting, and adjusting a sphere.

Who uses EN ISO 7278-2:2022/A1:2026?

EN ISO 7278-2:2022/A1:2026 is used by prover operators, calibration technicians, and inspection staff who work with pipe provers in petroleum measurement. It is also relevant to prover manufacturers and maintenance teams that size replacement spheres, select measurement tools, and prepare calibration reports.

Quality and metrology personnel use it when they need to confirm that a prover was checked for condition, leakage, and correct sphere inflation before calibration data were accepted.

What changed in EN ISO 7278-2:2022/A1:2026 from the previous edition?

EN ISO 7278-2:2022/A1:2026 amends EN ISO 7278-2:2022. The amendment:

• removes the earlier wording in 6.5.2 on sphere diameter checking
• adds 6.5.4, “Sphere inspection and sizing”
• adds pre-calibration leakage checking in 11.2
• adds Annex H item j on operational condition and recording temporary modifications

Which standards are used with EN ISO 7278-2:2022/A1:2026?

• EN ISO 7278-2:2022 - the base European Standard that this amendment modifies.
• ISO 7278-2:2022/Amd 1:2026 - the ISO amendment text that CEN approved without modification.
• API MPMS, chapter 4 section 9, part 2 - cited in the sphere ovality guidance as the reference for the 1% limit.

What does the EN ISO 7278-2:2022/A1:2026 document contain?

The amendment text is short and clause-based. It changes one existing subclause, inserts a new subclause on sphere inspection and sizing, adds a pre-calibration leak-check paragraph, and adds a calibration report item in Annex H.

It describes practical measurement methods for sphere diameter or circumference, including micrometres, slip rings, and tapes. It also gives the inspection points that matter during sizing, such as surface defects, wear, inflation condition, and ovality.

The document is used for design follow-up, field inspection, calibration work, and reporting. Its main value is to align the prover sphere procedure with a clearer, more traceable calibration practice.

SLOVENSKI STANDARD
01-september-2026
Merilni sistemi za nafto - 2. del: Načrtovanje, kalibracija in delovanje merilnika cevi
- Dopolnilo 1 (ISO 7278-2:2022/Amd 1:2026)
Petroleum measurement systems - Part 2: Pipe prover design, calibration and operation
- Amendment 1 (ISO 7278-2:2022/Amd 1:2026)
Mineralölmesssysteme - Teil 2: Auslegung, Kalibrierung und Betrieb von
Rohrprüfgeräten - Änderung 1 (ISO 7278-2:2022/Amd 1:2026)
Systèmes de mesurage des produits pétroliers - Partie 2: Conception, étalonnage et
fonctionnement des tubes étalons - Amendement 1 (ISO 7278-2:2022/Amd 1:2026)
Ta slovenski standard je istoveten z: EN ISO 7278-2:2022/A1:2026
ICS:
75.180.30 Oprema za merjenje Volumetric equipment and
prostornine in merjenje measurements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 7278-2:2022/A1
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2026
EUROPÄISCHE NORM
ICS 75.180.30
English Version
Petroleum measurement systems - Part 2: Pipe prover
design, calibration and operation - Amendment 1 (ISO
7278-2:2022/Amd 1:2026)
Systèmes de mesurage des produits pétroliers - Partie Mineralölmesssysteme - Teil 2: Auslegung,
2: Conception, étalonnage et fonctionnement des tubes Kalibrierung und Betrieb von Rohrprüfgeräten -
étalons - Amendement 1 (ISO 7278-2:2022/Amd Änderung 1 (ISO 7278-2:2022/Amd 1:2026)
1:2026)
This amendment A1 modifies the European Standard EN ISO 7278-2:2022; it was approved by CEN on 7 June 2026.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of
this amendment into the relevant 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 amendment 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, Türkiye 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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7278-2:2022/A1:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 7278-2:2022/A1:2026) has been prepared by Technical Committee ISO/TC 28
"Petroleum and related products, fuels and lubricants from natural or synthetic sources" 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 Amendment to the European Standard EN ISO 7278-2:2022 shall be given the status of a national
standard, either by publication of an identical text or by endorsement, at the latest by December 2026,
and conflicting national standards shall be withdrawn at the latest by December 2026.
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.
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, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 7278-2:2022/Amd 1:2026 has been approved by CEN as EN ISO 7278-2:2022/A1:2026
without any modification.
International
Standard
ISO 7278-2
Second edition
Petroleum measurement systems —
2022-11
Part 2:
AMENDMENT 1
Pipe prover design, calibration and
2026-06
operation
AMENDMENT 1
Systèmes de mesurage des produits pétroliers —
Partie 2: Conception, étalonnage et fonctionnement des tubes
étalons
AMENDEMENT 1
Reference number
ISO 7278-2:2022/Amd.1:2026(en) © ISO 2026

ISO 7278-2:2022/Amd.1:2026(en)
© ISO 2026
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 7278-2:2022/Amd.1:2026(en)
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 28, Petroleum and related products, fuels
and lubricants from natural or synthetic sources, Subcommittee SC 2, Measurement of petroleum and related
products, in collaboration with the European Committee for Standardization (CEN) Technical Committee
CEN/TC 19, Gaseous and liquid fuels, lubricants and related products of pet
...