Fire testing that takes place for factory-made homes is “likely to be sub-optimal”, the Ministry of Housing has been warned.
Research by Harlow Consulting and Edinburgh Napier University, published by the Ministry of Housing, sets out a range of issues with volumetric modular construction but, in the post-Grenfell environment, fire is the one likely to trigger the most concern.
The research was commissioned by the Ministry of Housing (then called the Department for Levelling Up) under the previous Conservative government.
The report states: “There is no standard fire test methodology which is directly applicable for volumetric construction; testing that takes place is likely to be sub-optimal. While there is insufficient evidence to suggest whether a fire is more or less likely in a modular building compared with a traditionally constructed building, the event of a serious fire is likely to 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 – unless these risks are mitigated via appropriate design, manufacture, and installation.
The repor recommends: “Further research is critical to have a clearer understanding of how materials (and combinations of materials/components) behave in modular buildings in the event of a fire, to feed into development of a standard fire testing methodology for volumetric construction.”
It continues: “There are very few industry standards directly applicable to volumetric construction, meaning that companies and practitioners often design and manufacture bespoke systems that cut across multiple standards. Different approaches in volumetric construction in relation to warranties, accreditation and certification create confusion. The resulting lack of uniformity and fragmentation that exists points to a need for commonality.”
Even if a prefab house is fully up to scratch on the fire safety front, there could be a risk of future owners or tenants making modifications that jeopardise this, the research found.
“Post-building completion, there is a potential risk that occupants, or builders without the relevant skills and understanding of the volumetric building, could make changes via repair and maintenance that compromise the integrity of the building. However, post-occupation phases of volumetric buildings and repair and maintenance issues do not appear to be major areas of research, and so it is not possible to understand the full extent of this potential risk.
“This issue is coupled with a lack of readily accessible long-term data about volumetric building performance which could provide insurers and lenders with greater confidence and reassurance about the longevity of the asset. Respondents point to the need for greater transparency and robust data; notably digital records of buildings to provide clear evidence of building methods, materials, testing, inspection and guidance for repair and maintenance.”
