"Protecting the Runehamar Tunnel in Norway with Promatect®-T against multiple fires, as part of the uptun research programme."
By Donald van Olst & René van den Bosch, Promat BV, Tunnel fire protection
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 Preparing the Runehamar fire tests, technical approach
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The effects of the intended fire loads on the heat release rate and the time temperature curve were unknown, prior to the Runehamar tests. Therefore TNO advised to fire test the intended construction to the Dutch RWS fire curve, exposing the panel to multiple fires. This RWS fire curve is still seen as the most severe hydrocarbon type of fire, due to it’s rapid temperature rise in the first 5 minutes, creating a thermal shock to the tunnel lining and reaching a maximum temperature of 1350°C. |
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The challenge for the PROMATECT®-T panels was described as follows:
- Being able to withstand 4 fires with maximum temperatures going up to approximately 1400°C.
- The temperature criterion on the rock was set to be 250°C. This was perceived to be a safe temperature for the rock material to avoid damage.
- The system was not allowed to show any integrity failures. This was applicable for the PROMATECT®-T panels and the sub-frame including the fixation materials.
- The aim was to design an easy to install system in view to reduce the installation time required to install the whole system, and to enable people to replace panels in the unlikely event of damaged panels (mechanical impact). Promat also wanted to have the possibility to extract fire exposed panels from the tunnel, in view to investigate these in the Promat Research and Technology Centre (PRTC).
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Pre-qualification of the intended system
Three consecutive fire tests were done at the Gerco laboratory in order to judge:
- the panels integrity after 3 fires
- the integrity of the chosen, easy to install, fixation materials
and system.
- Construction set-up during fire test
As shown on the above image (3.) the panels were hung on threaded rods (M6), which was also the case in the actual situation. Normally such a fixation method is not to be recommended for tunnels, which are in operation.
- Heated PROMATECT®-T panel and fixations
The heat sink effect through the steel fixation materials, threaded rods, was also investigated. Two out of four anchors were left unprotected (4.) and the temperature rise on the non-exposed face was measured on the protected, as well as the unprotected threaded rod. As can be seen from the below graph (5.), the temperature difference was perceived to be negligible. The maximum temperatures were respectively 193ºC and 174ºC. The maximum furnace temperature (in test 3) was recorded to be 1350°C, which is comparable to the maximum temperature of the RWS fire curve. The below graph (5.) shows the temperature recordings on the non-exposed face during test number 3.
- Thermocouple recordings during test 3 on the non-exposed face
Even after three fire tests the non-exposed face of the boards remained well below 200°C, whereas the maximum allowed temperature on the rock was 250°C. The heat dissipation in the gap between the PROMATECT®-T boards and the rock would also create some additional cooling effect.
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| Conclusions of pre-qualification tests |
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- During three consecutive fire tests no integrity failures were recorded for the PROMATECT®-T panels and the sub-frame, including the fixation materials.
- The maximum temperature on the non-exposed face of the PROMATECT®-T panels was 186 C, which is well below the criterion of 250°C.
- No major negative influence of penetrations of the threaded rods were found
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Based on the above experiences Promat was confident to proceed with the described system and offer it to the UPTUN partners for use in the full-scale fire test programme in the Runehamar tunnel in Norway. As we know now, the described system behaved very well, and all partners were satisfied with the results. |
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Further detailed explanation about the outstanding fire performance of PROMATECT -T boards, can be found in the paper by Dr. Octavian Anton, Director of the Promat Research and Technology Centre (PRTC), titled “Runehamar tunnel fire test – UPTUN, fire protection”. |
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