Lowering the fire safety height threshold from 18m to 11m – what are the implications?

Rt Hon Robert Jenrick – Secretary of State, Housing, Communities and Local Government - has revealed that the Government is considering lowering the building height threshold from its current 18 metres to 11 metres in relation to fire safety. This potentially brings all four-storey and higher residential buildings in England into scope with regards Part B of the Building Regulations governing the spread of fire.

In an update to the House of Commons, Jenrick revealed that the student housing block fire in Bolton in November 2019 shone a spotlight on the arbitrary nature of the 18-metre threshold, noting that the building was 17.8 metres high and therefore technically excluded from some of the more prescriptive fire safety requirements of the regulations.

What will the implications be for builders, developers, housing associations and other providers should the building height threshold be lowered to 11 metres?

What would be in scope?

In his statement to the Commons, the Housing Secretary made specific reference to sprinkler requirements as well as the ban on the use of combustible materials.

On sprinklers, the Government ran a consultation in late 2019 on proposals to reduce the height of buildings for mandatory sprinkler installation from 30 metres to 18 metres (in England), to bring it line with the combustible material height threshold.

The restrictions on the use of combustible materials in and on the external walls of high-rise (18 metres and higher) residential buildings (and any ‘specified attachments’) came into force in December 2018. We outlined its scope and meaning in an article in Issue 6 of our Technical Update newsletter.

Later in 2019, the Government re-iterated its positon that it also remained necessary to consider the health and safety risk from fire spread in all buildings, regardless of height. This is a specific reference to B4-(1) of Schedule 1, of the Building Regulations, which 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 height, use and location of the building”.

We also covered this in Issue 8 of our Technical Update newsletter.

An adjustment was made to these recent amendments to the Regulations  in December 2019 when the list of “specified attachments” was amended to remove devices “for reducing heat gain within a building by deflecting sunlight which is attached to an external wall.”

The recent amendments apply not only to new buildings, but also those undergoing a material change of use, and those where remediation works or maintenance works affect elements of the external wall.

What will the lower threshold mean for builders, developers and owners?

A consultation on lowering the height threshold for banning the use of combustible materials to 11 metres has been launched and is open to comments until 13 April 2020.

As noted above, it is already a requirement to consider the safety risk from the spread of fire in all buildings, regardless of height. In its July 2019 circular, the Government stated:

“Whilst the use of combustible materials within or attached to the external walls of buildings below 18 metres are not expressly prohibited, it is necessary to consider the risk from fire spread to health and safety in relation to buildings of any height.”

Reducing the height threshold to 11 metres will therefore expressly prohibit the use of combustible materials (external walls) in any residential building above 11 metres, while the requirement to consider the risk of fire spread will continue to apply for all other buildings.

Martin Taylor, Director of Regulatory Policy at LABC, said: “We welcome both MHCLG’s review of the ban on the use of combustible materials in and on the external wall of buildings and their publication of the analysis of the recent survey regarding the impact of the initial ban. We look forward to further details in respect of lowering the height threshold for sprinklers together with the detail of the wider reforms as we transition towards a new regime.”

While the consultation on mandating sprinkler installation in all 18 metre+ buildings (from 30 metres) has closed, we can expect the Government to make a further announcement in February with regards the lower 11-metre threshold.

Why 11 metres?

Following a review of the original ban on combustible materials, stakeholders suggested that 11 metres is an accepted limit of traditional external fire-fighting techniques. An 11-metre threshold is currently used in Scotland, though the Government admits there is no comprehensive research that supports the fire-fighting limit. It also admits that evidence to support any specific height threshold is limited, and while calling for such evidence it has also hinted that future height limits may be variable and be determined by the building type and use.


Please Note: Every care was taken to ensure the information in this article was correct at the time of publication. Any written guidance provided does not replace the reader’s professional judgement and any construction project should comply with the relevant Building Regulations or applicable technical standards. However, for the most up to date LABC Warranty technical guidance please refer to your Risk Management Surveyor and the latest version of the LABC Warranty technical manual.

Was this post helpful? /