Durability requirements for fire detectors mounted in engine rooms of heavy vehicles

Sammanfattning: This thesis was carried out at the Division of Combustion Engines within the Faculty of Engineering at Lund University in collaboration with SP Technical Research Institute of Sweden. The thesis was part of a project funded by the FFI program of VINNOVA, with the goal of creating a standardized test method when it comes to fire detection systems mounted in engine compartments of heavy vehicles. As of today, there are certifications regarding the fire suppression system but no appropriate test method for fire detection systems has yet been implemented. A stepping stone in the right direction of creating a standard for fire detection systems is by first looking at the durability requirements for fire detectors that are to be mounted in engine rooms of heavy vehicles. To better understand what can cause fire detectors to malfunction, a deeper knowledge of the operating principles of fire detectors is needed as well as which aspects influence the failure of detectors. The investigation is specified to engine compartments of heavy vehicles and to the physical phenomena arising in that environment. Six physical phenomena that arise in engine rooms due to the operating principles of the vehicle were seen as high priority aspects to be investigated further. These phenomena are: corrosion, ageing, heat and cold, vibrations and mechanical shocks, electromagnetic interference and finally the impacts of the intrusion of water, dust and dirt into the enclosures of electronic devices. The goal of this thesis was to find appropriate testing methods that are applicable to fire detectors that are to be mounted in the engine compartments of heavy vehicles with respect to their durability requirements. Test methods that are best suited for each of the physical factors mentioned earlier were chosen after consultations with experts at SP. Following this, appropriate test parameters were set by studying already existing standards and having dialogues with representatives of heavy vehicle manufacturers. The test parameters and the resulting durability requirements that have been recommended are based on the feedback from representatives of heavy vehicle manufacturers. Future work within this area is to conduct experimental tests of the fire detectors based on the test methods that have been suggested in this report. Furthermore, as the time frame of this thesis was limited, only the physical factors mentioned above have been studied. If there is further interest and if time is of no concern, the study of influencing physical phenomena can be expanded and more feasible results may be granted.