Heat release rates from heavy goods vehicle trailer fires in tunnels

Calculations of heat release rates (HRR) from four large-scale tests, with a mock-up of a Heavy Goods Vehicle (HGV) trailer, in a road tunnel are presented. Initial longitudinal ventilation rates within the tunnel were in the range of 2.8-3.2 m/s. Peak HRRs in the range of 66-202 MW were estimated. The peak HRRs were obtained between 7.1 and 18.4 min from ignition in the various tests. The HGV-trailer mock-up consisted of a steel rack system loaded with a mixed commodity of wood pallets and polyethylene pallets (Test T1), wood pallets and polyurethane mattresses (Test T2), furniture and fixtures with ten truck rubber tyres (Test T3), and paper cartons and polystyrene cups (Test T4). Each commodity was covered with a polyester tarpaulin in each test and ignited on the upstream, front end of the trailer. A comparison is made between the results presented here and other large-scale tests with HGV trailers in tunnels. The combined expanded relative standard uncertainty of the method used to determine the HRR was calculated to be 14.9%.