The Tunnel Fire Training and test centre, Centro Experimental "San Pedro de Anes" has long traditions in carrying out full scale fire tests, and has been a valuable partner in important tunnel fire research programs in Europe.
Generally for smoke testing applications the experts recommend oil based smoke systems instead of the normal water based smoke systems. This is because water based smoke evaporates relatively quickly, especially when combined with a hot air source to give thermal buoyancy, and hence it is not very representative of how smoke from a real fire would behave.
The ViCount smoke system produce a smoke with the smallest particle size in its class, but with a high temperature resistance. Many of today’s Computational Fluid Dynamics (CFD) models for smoke were based on the use of these systems. The smoke produced is not in itself hot, but it is extremely temperature resistant, so it can be added to the hot gases created by a burn tray or heater and used to trace how smoke would travel.
Critically, the ViCount smoke hardly evaporates at all. In a tunnel environment will smoke from these systems travel many kilometres, even with the tunnel jet fans operating. Using jet fans with water based smoke rapidly evaporates the smoke.
Such a system can be used to hot fire training, large scale exercises, functional testing etc.
A common mistake is to not pay attention to the cold environment and the cold surfaces in the tunnel says Mads Gilbert, specialist in anaesthesiology at the Emergency Medical Clinic at the University Hospital in Northern Norway. He says also that it is difficult to communicate and it is important to be familiar with conditions in a tunnel and to be ready for the real accident.