13 March 2002
Noise absorptive material used on West Rail
In response to allegations that some noise absorptive materials used in the construction of West Rail did not comply with tender specifications, a spokesman for the Kowloon-Canton Railway Corporation (KCRC) said today that the relevant specification originally prohibited the use of "mineral fibres", but not "any fibres".
"Mineral fibres do not constitute a health hazard. This has been authoritatively confirmed by the International Agency for the Research of Cancer (IARC), which has not included mineral fibres in its list of carcinogens.
"We originally excluded the use of mineral fibres on West Rail viaducts because, when we drew up specifications on the advice of West Rail’s acoustical consultants, we did not believe that this material would be sufficient to absorb the level of noise generated by West Rail trains.
"Subsequently, after exhaustive tests carried out by an independent materials testing laboratory, the Director, West Rail, his acoustical consultant and the Engineer for the viaduct contract were satisfied that the use of certain kinds of mineral fibres (eg rock wool) could meet the noise absorption requirements of the operating railway.
"The contractor was accordingly allowed to use rock wool on West Rail viaducts, but with the material suitably encased within panels which form the central noise barrier between the tracks.
"Such panels are widely used in noise barrier installations all over the world.
"The use of mineral fibres has always been permitted inside stations because the acoustical requirements in stations are not as stringent as those on viaducts.
"In any event, the use of such material will not result in any of its filaments being circulated within the ventilation and air conditioning systems of our stations. This is because the material is fully encased within panels or because it is embedded firmly in a ceiling tile," the spokesman said.