The World Road Association's (WRA) Road Tunnel Committee, on which I sit, is preparing an assessment of re suppression systems, which featured in the article on the Hindhead Tunnel (NCE 1 February).
The WRA's ssessment likely to recommend that the effectiveness of such systems should be investigated on a project-by-project basis in order to weigh the advantages of the installation (including limiting the fire size) against the disadvantages (such as the loss of visibility). A feasibility study accompanied by a risk analysis is also recommended.
Finally, a cost-benet analysis is required to determine whether the life safety and asset protection benets offered by a re suppression system are worth the capital and maintenance costs.
The Highways Agency is required to consider costbenet analysis, which does not support the installation of a suppression system in the Hindhead Tunnel. However, there may still be a strong case from stakeholders, such as the fire brigade, to install a fire suppression system, purely on safety grounds.
Note, however, that such systems may not necessarily be high pressure mist systems. For example, Japan and Australia have been specifying deluge systems for their road tunnels.
Fathi Tarada, director, Fire Safety Engineering, Halcrow Group, TaradaF@halcrow.com