Metro Magazine, January/February 2017

generally not perceived as the ultimate solution but as one of several tools necessary to limit the extent and consequences of bus fires occurring NEW TEST METHOD During recent years some major research initiatives have been taken to develop standardized tests for engine compartment fires Southwest Research Institute was contracted by The National Highway Traffic Safety Administration NHTSA in the U S to develop test apparatuses and test procedures to evaluate candidate fire detection and suppression systems for motorcoach engine compartments U S based commercial and industrial property insurance and loss prevention company FM Globals Research Division has developed FM Approval Standard 5970 Protection Systems for Heavy Duty Mobile Equipment Though focusing on heavy duty equipment rather than buses the applications 32 mETRO mAGAZINE JANUARY FEBRUARY 2017 metro magazine com Maximizing Passenger Safety with Fire Suppression Systems BY FREDRIK ROSÉN About two thirds of all bus fires start in the engine compartment according to researchers Various types of suppression agents are used including different sorts of dry chemical water mist foam aerosol gaseous agents or sometimes combinations of those Recent statistics from Sweden show that annually at least 076 of all buses in service will have a fire or smoke incident This is confirmed by surveys conducted in Germany where between 05 and 1 of all buses suffer from a fire incident every year which corresponds to at least 350 to 400 fires annually About two thirds of all bus fires start in the engine compartment according to researchers This area is a well known fire hazard that provides particular challenges for detection and suppression of fires Ventilation through fans and openings is necessary for cooling but will also increase fire intensity and spread The windy and often dusty environment in the engine compartment influences the possibility for fire detection and suppression This has naturally led to efforts of reducing the risks A way of increasing fire protection is to install an automatic fire suppression system in the engine compartment Such systems consist of one or more containers of suppression agent and a fire detection and activation system that releases the suppression agent in the event of fire A piping or tubing system is often used for the distribution of the suppression agent from the container to the different areas of the engine bay Some systems such as those with aerosol generators often have generators installed in the engine compartment and releases the agent directly from the generator In addition to suppressing the fire the systems are normally also designed to warn the bus driver via an alarm Various types of suppression agents are used including different sorts of dry chemical water mist foam aerosol gaseous agents or sometimes combinations of those The installation of automatic fire detection and suppression systems for buses has been recommended by fire researchers trade associations accident investigators and transport authorities It is Niklas Nordenskär Greater Stockholm Fire Brigade