Heat release rate

Thermal protection boards
Pre-qualification tests
Gas tempertures
Thermal protection and spalling
Heat release rate
Radiation levels near fire
Results and behaviour on the PROMATECT®-T lining

In the first two fire tests, test 1 and test 2, a pulsation of the fire was experienced during a time period when the fire was over 130 MW. This created a pulsating flow situation at the measuring station, where the measurements showed that the maximum velocity was pulsating in the range of 3 to 4 m/s down to a minimum in the range of 1 to 1.5 m/s. The frequency of the maximum velocities was about 45 seconds during this period.

heat release rate, fire resistant panel in tunnel

Since the air mass flow rate is dependent on the velocity measurements the HRR measurements also pulsate during this period. The HRR curves presented in the above figure are the actual HRR (average for test 1 and 2 during the pulsating period), although a correction has been made for the transportation time.

Test nr.
Time from ignition to peak HRR (min)
Linear fire growth rate
(R=linear regression coefficient) (MW/min)
Peak HRR
Estimated from laboraty tests (no target-inclusive target) (MW)
20,5 (0,997)
203 (average)
29,0 (0,991)
158 (average)
17,0 (0,998)
5 - 70 MW: 17,7 (0,996)

The fire growth rate appears to be relatively linear for all the tests when the fire becomes larger than 5 MW and less than 100 MW except for test 4 which has a peak HRR of 70 MW. Therefore, a linear curve fit for the different tests was used between 5 MW and 100 MW for test 1 to test 3 and between 5 MW and 70 MW for test 4. The linear regression coefficient R is shown in parentheses in the above table and is found to be very high in all cases (>0.99), indicating a highly linear behaviour during this period. The table shows that the wood pallets and mattresses (test 2) yield the fastest fire development (29 MW/ min), followed by the wood pallets and plastic pallets in test 1 (21 MW/min). Test 3 and test 4 were found to be very similar (17-18 MW/min).


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A report containing the set-up of the tests, the recordings of the data and the interpretation of the results was issued by Uptun, TNO and our company.

The report also contains a cd-rom with all the pictures and video’s of the set-up and the fire tests, as well as all the technical/scientifical papers.