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Standards & Regulations

Implications of BS EN 1366-4:2021 for linear joint seals

Paud Barret
Paud Barret
January 15, 2024

Paul Barrett, Head of Product Management, ROCKWOOL® UK, examines the key changes in standard BS EN 1366-4 and how they will help ensure firestopping products are thoroughly tested before certification.

What is BS EN 1366-4:2021?

Part 4 of the EN 1366 series, BS EN 1366-4 specifies a method for determining the fire resistance of linear joint seals based on their intended end use.

Linear joint seals are positioned in joints, voids gaps or other discontinuities within one or between two or more construction elements.

Normally such openings are denoted as linear because their length is greater than their width defined by a ratio of at least 10:1 in practice.

Joints are present in buildings due to the following reasons:

  1. Acceptable dimensions tolerances between two or more building elements, e.g. between non-load bearing walls and floors
  2. By design to accommodate various movements induced by thermal differentials, seismicity and movement induced by wind loads
  3. As a result of inadequate design, inaccurate assembly, repairs or damage to the building

The purpose of the BS EN 1366-4 test is to assess:

  1. The effect if a liner joint seal on the integrity and insulation of the construction
  2. The integrity and insulation performance of the linear joint seal
  3. The effect movement within the supporting construction on the fire resistance performance of linear joint seals
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What are the key changes to BS EN 1366-4?

The primary change to the way in which linear joint seals have been tested comes from the size of specimen that needs to be tested. Historically under BS test regimes, linear gap seals have always been tested on small scale furnace rigs that typically allow seals that are 900mm long. The introduction of EN test standards led to these types of seals being defined as having a typical ratio of at least 10:1 in practice. Based on this the EN 1366-4: 2006+A1:2010 test standard required that all joint seals are tested using this ratio. The standard required the following in terms of specimen size:

6.2 Size

A linear joint seal shall be of uniform design cross-sectional area and of the maximum length that can be accommodated in the separating element selected for test. For non-movement joints a shorter length may be used subject to a minimum of 900 mm. In order to avoid boundary effects, the distance between the long edge of the linear joint seal and the outer perimeter of the heated part of the separating element shall be not less than 200 mm at any point. A typical minimum length to width ratio for a linear joint seal is 10:1. In order to maintain this ratio a test furnace of appropriate dimensions shall be used.

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The adoption of the test standard, therefore meant that joint seals above 90mm in width could no longer be tested as a 900mm length (10:1). The result was that testing needed to be conducted on the large-scale furnaces, which typically measure 3m x 4m for floor furnaces and 3m x 3m for wall furnaces.  However, even these furnaces could not test linear joint seals greater than 360mm in width, on a floor or 260mm on walls. It was therefore commonly accepted within the UK, that testing conducted on a small scale furnace ‘generally in accordance’ with 1366-4: 2006+A1:2010, in the same way that all existing BS testing was conducted by using a minimum length of 900mm, could be used in support of 3rd party certificatin for the product.

The introduction of the latest revision of the test standard 1366-4:2021 incorporated a better way to test these larger seals, with a rewriting of section 6.2 of the standard:

Revised standard: 6.2 Size

 

A linear joint seal shall be of uniform design cross-sectional area and of the maximum length that can be accommodated in the separating element selected for test. For non-movement joints a shorter length may be used subject to a minimum of 900 mm. In order to avoid boundary effects, the distance between the long edge of the linear joint seal and the outer perimeter of the heated part of the separating element shall be not less than 200 mm at any point.

A typical minimum length to width ratio for a linear joint seal is 10:1 The length to width ratio may be <10:1 in case the heated length of the linear joint seal is ≥ 2600 mm.

The introduction of the ≥ 2600 mm meant that larger joint seals could be tested, relatively easily on UK furnaces and as such, all linear joint seals could be tested fully in accordance with the test standard. This has meant all classifications and 3rd party certifications can/should only accept data that has been obtained from testing fully in accordance with the latest test standard, with the linear joints being tested at a suitable test size. Testing that is not in accordance with the new standard should therefore not be used to support performance claims.

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What should I look for when specifying linear joint seals?

Architects and specifiers should make sure they specify linear cavity firestops that have been tested to the very latest standard. All classifications and third-party certifications can and should only accept data that has been obtained from testing fully in accordance with the latest test standard, with the linear joints being tested at a suitable test size. Testing that is not in accordance with the new standard should therefore not be used to support performance claims.

Does ROCKWOOL offer linear joint seals that are tested to BS EN 1366-4:2021 standard?

ROCKWOOL offers FirePro® SP FireStop EN which has been subjected to tests within large furnaces with minimum length of 2600mm, in accordance with the latest BS EN 1366-4:2021. In fact the whole range has undergone a rigorous testing schedule in accordance with the most recent test standard for linear joint seals, BS EN 1366-4:2021, including for use with Steel Frame Substrates and composite panels. Further to this, ROCKWOOL has tested SP FireStop EN against an ‘installation from below’ scenario, to support specific applications or reclad projects where installation options may be restricted. SP FireStop EN is available on NBS Source. Add SP Firestop EN to your specification.

Looking for further support on fire protection? Visit our FirePro Resource Hub.

Webpage history

Our experts continually review and update our articles when legislation changes or new information becomes available. 

First published: 16/01/2024

Product Management Headshot - Paul Barrett

ROCKWOOL Group