SPRINKLER SYSTEMS could be installed in the A303 Stonehenge and A3 Hindhead tunnels, the Highways Agency has confirmed this week.
The move would be unprecedented as no other UK tunnel uses a fire suppression system.
The Agency said that a series of tests across the world planned for this autumn will determine whether fire suppression can be used effectively.
'At present there is no consistent international approach to managing fires in tunnels, ' said Chris Jones, project director for the Stonehenge project.
There is a range of different types of system in use around the world, including conventional sprinkler systems, deluge systems, water mist systems and systems using compressed air foam.
The purpose of the suppression system also varies. Deluge systems are standard in tunnels in Australia and Japan, but are used to protect the asset rather than to save lives.
'We are more concerned about the advantages they offer in bringing the fire under immediate control, so that they can be used as a life saving tool, ' said Jones.
'But the problem is that the interaction of smoke with the water or mist from the suppression system is not yet fully understood. Could people escape? This is the subject of research and testing at the moment and in the light of this research we will make a decision.'
The Highways Agency has commissioned transport research body TRL to carry out two independent studies into tunnel safety. One of these will look at international best practice in post-incident recovery.
This study will be carried out for TRL by consultant Halcrow, which is also working on the design of Stonehenge tunnel in joint venture with Gifford.
Other tests are being carried out by research bodies around the world with the results pooled as part of an international effort, said Jones.
These tests should allow the Agency to make a decision by the end of the year.
This would allow time for sprinklers to be designed into the Stonehenge tunnel.
Construction work on the 2.1km long Stonehenge tunnel could start in spring 2005 if it gets the go-ahead from transport secretary Alistair Darling.
The public inquiry into the 1.9km long A3 Hindhead tunnel begins in September.