National foreword

This British Standard is the UK implementation of EN 1254‑20:2021+A1:2025. It supersedes BS EN 1254‑20:2021, which is withdrawn.

The start and finish of text introduced or altered by amendment is indicated in the text by tags. Tags indicating changes to CEN text carry the number of the CEN amendment. For example, text altered by CEN amendment A1 is indicated by .

The UK participation in its preparation was entrusted to Technical Committee NFE/34, Copper and copper alloys.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2021.

This European Standard was approved by CEN on 23 November 2020 and includes Amendment 1 approved by CEN on 5 December 2024.

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, Czechia, 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 foreword

This document (EN 1254‑20:2021+A1:2025) has been prepared by Technical Committee CEN/TC 133 “Copper and copper alloys”, 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 August 2025, and conflicting national standards shall be withdrawn at the latest by August 2025.

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 includes Amendment 1 approved by CEN on 5 December 2024.

This document supersedes EN 1254‑20:2021.

The start and finish of text introduced or altered by amendment is indicated in the text by tags .

The need for an amendment was based on the following points:

include a wall thickness table for copper alloy fittings used in systems according to EN ISO 15874, EN ISO 15875, EN ISO 15876, EN ISO 15877, EN ISO 21003 and EN ISO 22391.

This document is a supporting standard describing the test methods used by the other parts of the EN 1254 series.

EN 1254 comprises the following parts under the general title “Copper and copper alloys — Plumbing fittings”:

Part 1: Capillary fittings for soldering or brazing to copper tubes
Part 2: Compression fittings for use with copper tubes
Part 3: Compression fittings for use with plastics and multilayer pipes
Part 4: Threaded fittings
Part 5: Capillary fittings with short ends for brazing to copper tubes
Part 6: Push-fit fittings for use with metallic tubes, plastics and multilayer pipes
Part 7: Press fittings for use with metallic tubes
Part 8: Press fittings for use with plastics and multilayer pipes
Part 20: Definitions, thread dimensions, test methods, reference data and supporting information

According to the CEN-CENELEC Internal Regulations, the national standards organisations 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.

1 Scope

This document contains definitions, thread dimension, reference data (minimum bore and wall thickness), supporting information (assembling instructions) and describes the test methods referenced by other parts of the EN 1254 series.

Thread dimensions comprise: wall thickness at threaded portions of fittings, dimensions of tail pipe ends for swivel fittings, dimensions of gas union connectors, thread dimensions and thread profile.

Test methods comprise: leak tightness under internal hydrostatic pressure, leak tightness under internal pneumatic pressure, integrity of fabricated fitting bodies or having an 'as cast' microstructure, resistance to pull out of joints to metallic tubes, resistance of joints with metallic tube to vibration, resistance of joints to static flexural force, leak tightness of joints under vacuum, the resistance of joints to temperature cycling, detecting non-pressed fitting ends, resistance to stress corrosion, detection of a carbon film on the surface of copper fittings, determination of mean depth of dezincification, resistance of joints to pressure cycling, disconnection and re-use, determining if the diameter and/or the length of engagement of a capillary end is/are within the specified tolerance, determining the minimum length of engagement of an integral solder or brazing ring socket having a formed groove.

2 Normative references

3 Terms and definitions

4 Thread dimensions

4.1 Wall thickness at threaded portions of fittings

4.2 Dimensions of tail pipe ends for swivel fittings

4.3 Dimensions of gas union connectors

4.4 Threaded end dimensions

4.5 Minimum bore and cross-sectional area of fittings

5 Test method for leak tightness under internal hydrostatic pressure

5.1 Introduction

5.2 Principle

5.3 Apparatus

5.4 Test piece

5.5 Procedure

6 Test method for leak tightness under internal pneumatic pressure

6.1 Introduction

6.2 Principle

6.3 Apparatus

6.4 Test piece

6.5 Procedure

7 Integrity of fabricated fitting bodies or having an 'as cast' microstructure

7.1 Introduction

7.2 Principle

7.3 Apparatus

7.4 Test piece

7.5 Procedure

8 Test method for resistance to pull out of joints to metallic tubes

8.1 Introduction

8.2 Principle

8.3 Apparatus

8.4 Test assembly

8.5 Procedure

9 Test method for the resistance of joints with metallic tube to vibration

9.1 Introduction

9.2 Principle

9.3 Apparatus

9.4 Test assembly

9.5 Procedure

10 Test method for the resistance of joints to static flexural force

10.1 Introduction

10.2 Principle

10.3 Apparatus

10.4 Test piece

10.5 Procedure

11 Test method for leak tightness of joints under vacuum

11.1 Introduction

11.2 Principle

11.3 Apparatus

11.4 Test piece

11.5 Procedure

12 Test method for the resistance of joints to temperature cycling (liquid applications)

12.1 Introduction

12.2 Principle

12.3 Apparatus

12.4 Test assembly

12.5 Procedure

13 Test method for the resistance of joints to temperature cycling (fuel gas applications)

13.1 Introduction

13.2 Principle

13.3 Apparatus

13.4 Test assembly

13.5 Procedure

14 Method for detecting non-pressed fitting ends

14.1 Introduction

14.2 Principle

14.3 Apparatus

14.4 Test piece

14.5 Procedure

14.6 Results

15 Determination of resistance to stress corrosion

15.1 Introduction

15.2 Test piece

15.3 Procedure

15.4 Test report

16 Test method for detection of a carbon film on the surface of copper fittings

16.1 Preparation of the test piece

16.2 Procedure

16.3 Detection and assessment of films

17 Determination of mean depth of dezincification

17.1 Introduction

17.2 Procedure

17.3 Expression of results

18 Test method for the resistance of joints to pressure cycling

18.1 Introduction

18.2 Principle

18.3 Apparatus

18.4 Test pieces

18.5 Procedure

19 Test method for disconnection and re-use

19.1 Introduction

19.2 Principle

19.3 Apparatus

19.4 Test assembly

19.5 Procedure

20 Method for determining if the diameter and/or the length of engagement of a capillary end is/are within the specified tolerance

20.1 Principle

20.2 Apparatus

20.3 Test piece

20.4 Procedure

20.5 Results

21 Method for determining the minimum length of engagement of an integral solder or brazing ring socket having a formed groove

21.1 Introduction

21.2 Principle

21.3 Apparatus

21.4 Test piece

21.5 Procedure

21.6 Results

22 Minimum wall thickness

Bibliography

BS EN 1254-20:2021+A1:2025

Copper and copper alloys. Plumbing fittings - Definitions, thread dimensions, test methods, reference data and supporting information

Current

Published:

28 Feb 2025