National foreword

This British Standard is the UK implementation of EN 1364‑6:2025.

The UK participation in its preparation was entrusted to Technical Committee FSH/22/-/7, Non loadbearing separating elements.

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

BSI, as a member of CEN, is obliged to publish EN 1364-6:2025 as a British Standard. However, attention is drawn to the fact that during its development, the UK committee voted against its approval as a European Standard. The main reasons for this negative vote are as follows.

The Introduction to the standard states that a European reference scenario has not been established but is ongoing, and so the standard cannot be used to imply performance of an external façade system in which the open-state cavity barrier is included. It does state that the test results can be used to supplement evidence of cavity barrier performance in faced systems already accepted by current local regulations.
Though Subclause 6.2 of this standard does not make reference to minimum length to width ratios for an open state seal, the UK committee would advise users to note that the Introduction to BS EN 1366-4:2021 details that linear joint seals are normally defined by a typical ratio of at least 10:1, and Subclause 6.2 of BS EN 1366-4:2021 points out that the length to width ratio may be < 10:1 in case the heated length of the linear joint seal is ≥ 2 600 mm.
Figure 1 and Figure 2 leave room for interpretation on the permissible/intended distance from the furnace opening to the installation location of the specimen. The UK committee advises that this be considered in association with combustible substrate and/or any insulation material which may be present and the position of the cavity barrier in relation to the cavity edge.
Figure 2 and Clause 9 do not include unexposed surface thermocouples on the inner face of the twin leaf cavity substrates 25 mm above the cavity barrier. The UK committee believe that thermocouples at these locations are important for monitoring insulation performance.
Figure 2 does not include a minimum height of the twin leaf cavity wall substrates.
Clause 7 does not cover variations in associated supporting construction.

The UK committee advise users to be aware of these concerns when applying this standard, particularly in the context of a fire risk assessment of the application.

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 31 May 2025.

This European Standard was approved by CEN on 1 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 1364‑6:2025) has been prepared by Technical Committee CEN/TC 127 “Fire safety in buildings”, the secretariat of which is held by BSI.

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 has been prepared under a standardization request addressed to CEN by the European Commission. The Standing Committee of the EFTA States subsequently approves these requests for its Member States.

The test method is needed in support of ETAG 026‑5 for cavity barriers.

Any feedback and questions on this document should be directed to the users’ national standards body. 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.

Introduction

Cavity barriers are provided within buildings to restrict the spread of smoke and fire in concealed spaces. Cavity barriers can be ‘closed’ e.g. in roof voids, under raised or hollow floors, between the inner and outer layers of walls such as in timber framed construction; or they can be ‘open’ e.g. as used in ventilated facade systems, roof eaves, rain screen cladding systems.

This document describes tests to measure the ability of a representative specimen of an open-state cavity barrier to resist the spread of fire from one side to another. A representative sample of a cavity barrier is exposed to a specified regime of heating and pressure. The performance of the test specimen is monitored on the basis of criteria in EN 1363‑1. The fire resistance of the tested construction is expressed as the time for which the appropriate criteria have been satisfied.

The principles embodied in this method follow those embodied in EOTA TR31 the fire resistance test for closed cavity barriers published in 2008. However, TR31 is not applicable to open-state cavity barriers and consequently this method has had to be adapted to include these.

Testing of closed cavity barriers is not in the scope of this document. Test methods for closed cavity barriers are covered by EN 1366‑4. Testing of large-scale closed cavity barriers are covered by EN 1364‑1.

Reference scenario and limitations:

Closed cavity barriers whose function is to close a gap between fire resistant elements of building structure fall within the scope of the small room fire scenario where ISO 834‑1 has been recognized as the reference fire resistance test.

For open-state cavity barriers e.g. those used in ventilated facades, rain screens and roof eaves; a European reference scenario has not yet been established. Work is on-going to develop a full-scale façade test and it is expected that this method will be correlated to that full-scale test. Consequently, for the time being results of tests to this document cannot be used to imply performance of an external facade system in which the open-state cavity barrier is included. The test results can be used as supplementary evidence of cavity barrier performance in façade systems already accepted by current local regulations. Further information is given in Annex A.

Caution:

The attention of all persons concerned with managing and carrying out this fire resistance test, is drawn to the fact that fire testing can be hazardous and that there is a possibility that toxic and/or harmful smoke and gases may be evolved during the test. Mechanical and operation hazards can also arise during the construction of the test elements or structures, their testing and disposal of test residues.

An assessment of all potential hazards and risks to health should be made and safety precautions should be identified and provided. Written safety instructions should be issued. Appropriate training should be given to relevant personnel. Laboratory personnel should ensure that they always follow written safety instructions.

1 Scope

This test method specifies methods for determining the fire resistance of open-state cavity barriers and is intended to be used in conjunction with EN 1363‑1.

This document is applicable to non-loadbearing vertically or horizontally oriented open-state cavity barriers, which are designed to close and provide fire separation in the event of fire.

Open-state cavity barriers in facades, where the fire exposure comes as a result of a breaking window and allowing a developed fire to come into contact with the façade, can be tested to the optional “flame” criteria.

This document is not applicable to cavity barriers containing penetration seals, which are covered by EN 1366‑3.

This document is not applicable to closed cavity barriers, which are covered by EN 1366‑4.

2 Normative references

3 Terms and definitions

4 Test equipment

5 Test conditions

5.1 Heating conditions

5.2 Pressure conditions

6 Test specimen

6.1 General

6.2 Size

6.3 Number

6.4 Design

6.5 Construction

6.6 Verification

7 Installation of test specimen

7.1 General

7.2 Standard supporting construction

7.3 Splice locations for open-state cavity barriers

8 Conditioning

9 Application of instrumentation

9.1 Thermocouples

9.2 Pressure

10 Test procedure

10.1 General

10.2 Furnace control

10.3 Evaluation of integrity

10.4 Observations during the test

10.5 Termination of test

11 Performance criteria

11.1 General

11.2 Open-state cavity barriers

11.3 Expression of results

12 Test report

12.1 General

12.2 Reports of tests undertaken on open-state cavity barriers

13 Field of direct application of the test results

13.1 Open-state cavity barriers

Bibliography

BS EN 1364-6:2025

Fire resistance tests for non-loadbearing elements - Open-state cavity barriers

Current

Published:

31 May 2025