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.
While active-fire-protection systems such as sprinklers are an important and visible element of a building’s fire strategy, the building fabric also has a major role to play in protecting people should a fire break out. In particular, firestopping products are a vital element of passive fire protection for every building, helping to stop or slow down the progress of fire and smoke in gaps or joints between different construction elements, e.g. at the junction between an external cavity wall and every compartment wall and compartment floor.
The standard
Guiding the industry in this area, BS EN 1366 is a series of test standards that specify test methods, specifically fire-resistance tests for service installations. Specifically, part four of the BS EN 1366 series outlines a method for determining the fire resistance of linear joint seals based on their intended end use.
Linear joint seals are positioned in voids, gaps or other discontinuities within one, or between two or more, construction elements. 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.
There can be several reasons why such joints exist in a building. For example, certain dimensional tolerances between two or more elements can be acceptable in some circumstances; or joints have been designed to accommodate various movements caused by thermal differentials, seismic activity or wind loads. Last, but not least, design or assembly mistakes, repairs or damage to the building can also result in joints.
The purpose of the BS EN 1366-4 tests is to assess the effect of a linear joint seal on the integrity and insulation of the construction, and to determine the integrity and insulation performance of the linear joint seal. It will also examine the effect of any movement within the supporting construction on the fire-resistance performance of the linear joint seals.
The key changes in the new standard
BS EN 1366-4 was updated in 2021 and a primary change is the way in which linear joint seals are tested determined by the size of specimen that needs to be tested. Historically under British Standard 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 BS EN 1366-4: 2006+A1:2010 test standard required that all joint seals are tested using this ratio as stated in the standard: ‘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 900mm. 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 200mm 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.’ (Section 6.2 “Size”, BS EN 1366-4: 2006+A1:2010)
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 BS EN 1366-4: 2006+A1:2010 in the same way all existing BS testing was conducted by using a minimum length of 900mm, could be used in support of third-party certification for the product.
The latest revision of the test standard BS EN 1366-4:2021 incorporated a better way to test these larger seals, with a rewriting of section 6.2 of the standard: ‘… 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 ≥ 2600mm.’
The introduction of the ≥2600mm 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 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.
Beyond the standard
Test standards ensure that claims about the performance of construction materials in specific environments can be proven. They provide an important framework for manufacturers, designers and specifiers to inform their choice of building materials.
Standards are updated as new, more precise testing methods are developed and new materials enter the market. It is therefore important to stay informed and check to ensure products intended for specification have valid testing, classification and certification in accordance with the latest standards.
Approved Document B (ADB) states that joints between fire-separating elements should be firestopped, this would include voids between compartment elements and the external envelope of the building. Consultants should therefore ensure that products used for firestopping these joints have been appropriately tested to the relevant standards.
In buildings where the ban on combustible materials apply according to ADB – plus those where the building owner has elected to use non-combustible materials for improved fire performance – increasingly firestop systems manufactured from stone wool are being installed.
Stone wool is made from volcanic rock and hence is naturally non-combustible and can withstand temperatures exceeding 1,000°C. Likewise, it is unaffected by the impact of changes in temperature or humidity. As well as meeting non-combustibility requirements, stone wool also provides acoustic and thermal performance, meaning stone-wool firestop systems will not compromise the overall insulation performance of the facade system.
Evolving solutions
With the new BS EN 1366-4 test protocol in place, ROCKWOOL has evolved its product range to suit. In particular, 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. SP FireStop EN has been tested with various substrates which include steel-frame systems and composite panels and has also been tested in accordance with BS EN 1364-4:2014 for curtain-wall systems. 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.
Firestop systems can make all the difference in the event of a fire by giving people the time to escape and allowing the emergency services to save lives and property. Although construction is a fairly traditional industry, new methods and materials are being introduced all the time. This means fire-protection systems and their testing processes need to be reviewed regularly and adapted if necessary. The new update to BS EN 1366-4:2021 has made the testing of larger linear joints more accurate, further contributing to the fire safety going forward.
Staying abreast of new developments in construction materials and methods is key for consultants, architects, specifiers and installers. Manufacturers like ROCKWOOL support these efforts by providing information through a range of CPD seminars and technical background materials like whitepapers.
For more information visit https://rockwool.link/ifp-dec
About the Author
Paul Barrett
Paul Barrett is Head of Product Management at ROCKWOOL and is at the forefront of product innovation across the company’s full portfolio. Leading an ongoing programme of independent testing and certification, Paul is responsible for maintaining the highest quality levels and compliance with the latest standards.
