Fire Regulations for Commercial Roofing: Are You In the Know?
In our latest newsletter, Technical Manager Sam Rigden MCIOB takes a detailed look at the current building regulations, and Approved Document B updates for commercial roofing projects.
In May 2018, the Building a Safer Future, Independent Review of Building Regulations and Fire Safety: Final Report , more commonly known as the Hackitt Review, was published and laid out more than 50 recommendations to create a more robust regulatory framework for the building industry as a whole, with particular focus on fire safety.
The government began conducting consultations within the industry to work out how to implement these recommendations effectively. This has led to incremental updates to the Building Regulations through the introduction of new legislation, such as the Fire Safety Act 2021 and the Building Safety Act 2022 .
This has significantly changed the regulatory rules and responsibilities for fire safety in a relatively short time. With the release of the latest amendments to Approved Document B on 1st December 2022 and its six-month transition period expiring on 1st June 2023, it is essential to get up to speed with the current fire regulations and how they apply to commercial roofing.
Whilst this article and the associated complete technical guide attempt to make the requirements as clear as possible, if you would like any clarifications or guidance, please get in touch with one of Garland UK’s highly trained Technical Managers.
Building Regulations
The Building Act 1984 is the legislation that forms the framework of all UK building regulations. This is updated directly by parliament and through additional legislation, most recently the Fire Safety Act 2021 and the Building Safety Act 2022 . Building Regulations are a set of standards and requirements that must be met when constructing, altering, extending, or converting buildings. These regulations cover a wide range of areas, including energy efficiency, fire safety, structural stability, access for disabled people, and ventilation, among others. They ensure that buildings are safe, healthy, and sustainable for their occupants and the wider environment. Local authorities enforce the regulations, and failure to comply can result in legal action.
There are a series of Approved Documents that specify how to comply with the Building Regulations; Approved Document B (ADB) deals with fire safety.
Approved Document B (ADB)
Approved Document B (ADB) explains how to fulfil the requirements for fire safety in the Building Regulations. It is divided into ADB volume 1 (Dwellings) and volume 2 (Buildings other than dwellings). Requirement B3: Internal fire spread (structure), and Requirement B4: External fire spread dictates the requirements that apply to the building envelope, external walls and roofing.
ADB’s last full update was in 2019 to attempt to make the document easier to understand and important to introduce the new Regulation 7(2) of the Building Regulations, which banned combustible materials in or on external walls of the newly defined ‘relevant buildings’. In most cases combustible materials should also not be used on the newly defined ‘specified attachments’, which include elements attached to the external walls of a building, most notably balconies. The LRWA, NFRC and SPRA have produced a useful Guidance Document to help clarify and apply these changes. It was additionally amended in 2020, most recently in December 2022.?
Relevant Building
A Relevant Building is any building that is 18m above ground level and contains one or more dwellings, an institution, or a room for residential purposes. It now also includes student accommodation, care homes, sheltered housing, hospitals, dormitories in boarding schools, hostels and boarding houses.?
In fact, for all intents and purposes, no residential building above 11m from ground level can now use any combustible materials in or on external walls.?
Some exclusions to the definition of a ‘Relevant Building’ include military barracks, any accommodation provided by the MOD and secure residential institutions. You can see the full details of exclusions here.
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Specified Attachments
For Specified Attachments, this new term has caused a great deal of confusion; what should be considered a flat roof and what should be considered a balcony? It appears to contradict the European Commission Directive 2000/553/EC and Regulation 7(3) if the definition of a balcony is deemed to include an insulated roof. The flat roofing industry, working with other relevant bodies, has come to a common understanding, which is now also mirrored in BS8579:2020 ‘Guide to the Design of Balconies and Terraces’.
Attached balconies are differentiated from roof terraces in that they are not over habited and conditioned spaces. They are usually bolted to or cantilevered from the external wall. Also included are most inset balconies. For the purposes of Approved Document B, balconies are not deemed to be roofs unless they are designated to provide means of escape.
For areas that are correctly deemed to be balconies, i.e. ‘specified attachments’ on ‘relevant buildings’, non-combustible material must be used. However, there is an exception made by Regulation 7(3) that excludes the waterproofing membrane from this requirement.
Termination of Roofing Materials on ‘Relevant Buildings’
The exception to the use of a non-combustible membrane in Regulation 7(3) has caused another serious area of confusion, how do you safely terminate a roof or balcony where it abuts a wall. Again the LRWA, NFRC and SPRA Guidance Document has resolved this issue.
Insulation used as a thermal break on the face of a wall or abutment is exempt from the non-combustible ban, provided it is no thicker than 60mm and does not go higher than 150mm above the finished roof level or walking surface. If for any reason the thermal break goes higher than this, or if it crosses an internal fire compartment line, then non-combustible insulation must be used.
Requirement B3: Internal fire spread (structure)
Fire compartmentation is used internally to stop the spread of fire throughout a building. This basically entails separating the building into compartments using fire-resistant walls, floors, and doors, so that the fire is contained within a single compartment in the event of a fire.
Where a fire compartment wall forms a junction with the structure of a roof, the roof covering must be classified to BROOF(t4) and extend 1500mm on either side of the wall. The roofing substrate or deck must be classed A2-s3 d2 or better. In buildings under 15 meters high from ground level and purpose groups 1,2,3 or 5 other than 2(a) a substrate of B-s3 d2 or worse can be used.?In all cases, fire-stopping is to be carried up to the underside of the roof covering.
Requirement B4: External fire spread
B4 sets out the requirements to prevent the external spread of fire on external walls and roofs. It states that:
●??????The external walls of the building shall adequately resist the spread of fire over the walls and from one building to another, having regard to the building's height, use and position.
●??????The roof of the building shall adequately resist the spread of fire over the roof and from one building to another, having regard to the use and position of the building.
The outermost material used for external walls must meet the combustibility requirements in ADB Table 10.1. The distance to the boundary of the property, its height and its use dictate what materials can be used.?
The Complete Guide: Fire Regulations for Commercial Roofing
If you would like to learn more about Fire Regulations for Commercial Buildings, you can read and download the complete technical article here , which includes additional details on Fire Testing Classifications, Fires Safety Orders and how roofing can be upgraded to meet Safety Standards.