Sir: Your coverage of the report into the fire on the cross-Channel ferry Sally Star ("Blaze on ferry `exposed failings in safety drill' ", 31 October) highlights the possibility of further ferry engine room fires if halon is misused.
To be fully effective, halon must be released as soon as fire is detected. Breathing apparatus is not required, as a concentration of maximum 5- 6 per cent in the affected area will extinguish fire; 94-95 per cent air remains to sustain life. Unlike carbon dioxide, halon does not consume oxygen: it eliminates fire by chemical break-up of the fire molecules.
Halon is widely used in the UK and elsewhere to protect computer rooms, telephone exchanges and other enclosed spaces where secondary damage to contents could be as costly as the fire itself. In none of these places is breathing equipment felt to be necessary. Staff are trained to make an orderly exit before, during or after the automatic release of halon by heat or smoke sensors.
There appears to have been no understanding of halon's role on the Sally Star. Eurotunnel is not immune from this ignorance of halon's qualities. It is described in the published safety document as an "agent of last resort" on the shuttle. Eurotunnel intends to attempt evacuating passengers before releasing halon. This is wasting time, halon and probably passengers' lives. Halon's ability to fight fire diminishes with every wasted second.
Internaft (Shipping Consultants)
London, SW1Reuse content