Fire safe compliance for an ‘out of sight’ building asset

The Independent Review of Building Regulations and Fire Safety has led to increased attention on fire safety. While much of this has been focused on high-rise residential properties, it is crucial that the specification of all building materials and systems adhere to current fire regulations and ensure the safety of building occupants. 

A technical white paper, supported by Zurich, entitled “Broof(t4) Compliance: Fire penetration performance and spread of flame” is available to download here: https://bit.ly/3j3gMf4

Daren Fraser, Head of Technical at Langley Waterproofing Systems Ltd looks at compliance in flat roof installations in line with fire regulations.

A recommendation of the Independent Review of Building Regulations and Fire Safety is that there be a duty holder responsible “throughout the life cycle of the building”, to ensure that it is built safely, refurbished safely and maintained safely.

It is crucial that regulatory and legislative compliance is considered beyond initial specification and should extend to maintenance, repairs and replacements. Consideration is often given at the initial specification and installation to ensure full compliance, but it is essential that any subsequent work does not undermine this compliance. 

Only robust system tests and certification in real life scenarios should be obtained and fully understood by sufficiently competent assessors and peer reviewers who guarantee work.

Fire Regulations

For roof installations, one of the key sources of regulation and guidance in England is Approved Document B (Fire Safety) of the Building Regulations. In particular section B4, which relates to the resistance to the spread of fire from an external source (as opposed to fire from within the building) as well as resistance to fire spreading across the roof. Approved Document B provides guidance on mitigating fire risks in all areas of the building. One of the main dangers for roofs specifically is that burning airborne material or heat from a nearby fire will cause the roof to ignite and the fire to spread. As such it states minimum distances between buildings and provides guidelines on the required fire resistance of building materials. 

Testing and Certification

The fire resistance of a roofing material is evaluated on two criteria – the penetration of flame and spread of flame. Although the standard is largely harmonised, the testing process does include specific measures designed to meet the legislative requirements of different countries. The specified test for the UK has two stages designed to meet the stricter requirements demanded by UK regulations. If the system passes the required criteria, it receives Broof(t4) classification. A Broof(t4) classified system is referred to as ‘unrestricted’ or ‘low vulnerability’ and therefore has no minimum distance requirement between adjacent buildings. 

Anything less than a system that meets the Broof(t4) classification means that the building is more susceptible to fire risk. 

Ensuring compliance

It is crucial to interrogate the system information to ensure the selected solution meets the requirements and fully complies with regulations. Evidence must be available that the system has undergone independent testing and verification of its performance. For example, British Board of Agrément (BBA) certification will confirm compliance with the relevant Building Regulations and the Broof(t4) classification.

However, decision makers need to be aware of issues that may affect the installed performance of the roof system. One of the most common issues is a system that has not been tested with the type or thickness of insulation that has been specified for the build or works. If the system has only been tested with a specific type and thickness of insulation it is difficult to accurately assess how that specific system build up will perform in the event of fire.

Fire resistance classifications apply to the whole roof system rather than individual components, any changes to the composition of the solution will invalidate the ratings and accreditations. A particular risk is that the substituted components are more combustible than the ones tested and therefore pose a significant fire risk if installed. 

Roofing systems should only be installed by contractors who are trained to do so. To assist decision makers, leading system suppliers will have a database of approved contractors who are certified to install the system. It is also best practice to choose a supplier that monitors the installation work to ensure it is carried out with all the correct components and in the correct configuration.

Fire safety is one of the key considerations when selecting roof system for a new building or refurbishment. As such it is important that system information is interrogated with testing certification evidence to ensure the chosen solution can demonstrate that it is safe and compliant.

Langley also has a ‘Mitigating Fire in Flat Roofing’ CPD seminar, available to be delivered live with an opportunity for a Q&A session at the end.

To book email cpd@langley.co.uk