Preventing firefighter & evacuee entanglement, electrocution, and obstruction risks in timber buildings on fire.
This research was funded by the Fire Service Research & Training Trust, and supported by the RISCAuthority, KLH and Midfix.
Why this matters
Construction in the UK and around the world is in a state of flux as we seek low carbon alternatives to traditional construction materials like concrete and steel. Whilst these changes are supported by core research – mostly to do with structure and structural integrity under fire, such is the rate of change that it will never keep abreast of implementation, and some challenges will only manifest in time with the experience of construction, use and occupation. Hopefully (and usually) these will only demand minor ‘tweaks’ to be made later but occasionally major issues do arise that have far-reaching implications – such as the progressive collapse of large panel system buildings like Ronan Point.
Context
This report aims to pre-emptively address a believed inevitable detrimental outcome of the necessary move to net-zero construction methods that may significantly raise the risk of firefighter and occupant harm from ‘entanglement’, ‘electrocution’ and ‘crush’ risks caused by detachment of ceiling mounted M&E structures in mass timber buildings. Such detachment of services also has the capability to render other fire protection systems (lighting, detection, smoke removal, alarm, suppression) inoperative, break down passive fire boundaries as large ventilation fall from their boundary interfaces, and even damage gas fuel lines.
Key insights
- Fixings in wood are much weaker post-fire.
- There is a high risk that Mechanical and Electrical (M&E) services could fall during a fire on a timescale relevant to evacuation an intervention (<15minutes)
- Load capacity during fire was shown to decrease with increasing fixing diameter (fail earlier).
- Only fire testing under load can accurately describe the retention capability of fixings during a fire.