Modular construction projects should undergo fire safety testing prior to completion, the London Fire Brigade (LFB) has said
As reported by Construction News, LFB has called for modular structures to undergo individual fire tests due to their “very bespoke nature”. This more rigorous testing would enable a better “understanding of the performance of the structure when subject to heating and cooling as a result of a fire incident”.
Such structures, built in a factory and then assembled on site, may not mirror the fire behaviour of traditional construction, the Brigade said, adding that regulatory frameworks for modular systems are still in their infancy. Of high concern was an “inconsistent approach” when it comes to the amount of detail provided by designers and developers to show compliance of modular structures with Building Regulations, with issues arising from hidden voids, unsealed penetrations, compromised cavity barriers, and unverified joints.
“It is […] the LFB’s experience that a number of projects utilising modern methods of construction [MMC] have not fully recognised or addressed the need to demonstrate the performance of the design in regard to fire,” the report stated.
Developers should engage with fire engineers on all projects involving MMC to assess the impact of fire on these structures, LFB added.
Business Enquirer writes that LFB’s call to action has implications for a wide range of stakeholders, including manufacturers and system providers, to ensure that modular units are tested in conditions that “replicate site assembly, stacking, connectivity, and service penetrations”; developers; regulators and insurers; and contractors and site teams.
Speaking to Construction News, Dirk Vennix from Buildoffsite, a modular industry body, said that more rigorous processes in MMC prior to structures arriving on-site could lead to an increase in cost and time. There is also the issue of insufficient testing capacity and facilities to meet the demand.
“As a result, significant delays in pipeline and construction would be expected which is the last thing our members want given they have the capacity to help deliver commercial projects and build 1.5 million homes,” Vennix said.
In an assessment of risk report published earlier this year, the Brigade warned of a specific concern regarding the “development of cross laminated timber structures and modular construction methods and performance of these materials during fire or collapse”. Its implication on fire services is that such incidents may develop in an “unfamiliar way to crews”.
As previously reported by the FPA, research carried out in 2024 examined the fire safety performance of volumetric modular construction, stating that whilst there was “insufficient evidence” to suggest whether a fire in a modular construction was more or less likely than in a traditionally constructed building “the event of a serious fire may result in more serious consequences in a modular building if the choice has been made to use combustible elements in the voids and cavities through which fire and smoke can travel quickly”.