Fire Safety Science Digital Archive

Flammable vapours and gases are handled in many industries and the danger of explosion exists wherever they may form mixtures with air within the flammability limits. Plant in which there is a possibility of these mixtures occurring should be designed so that the minimum amount of damage would be caused by an explosion that may result from the ignition of such mixtures. The insertion of flame arresters into the plant and the provision of explosion reliefs are two ways of reducing the damage caused by such explosions. A flame arrester acts by preventing an explosion from propagating from one part of a plant to another. The function of explosion reliefs is to reduce the maximum pressure reached in the explosion to a value which the plant can withstand. In view of the lack of the full data necessary for the efficient design of such protective devices, the Joint Fire Research Organization were asked, by the Faotory Inspectorate in 1954 to carry out research on the mechanism of operation of flame arresters and relief vents and to obtain data which would allow them to be adequately designed. This research was started in 1955 and is continuing at the present time. While the work was in progress, visits were made by the research staff to a number of industrial premises where these devices are installed, to obtain first hand information on the practical conditions of their use. These visits, while confirming that there was a wide range of conditions of use where more design data was essential, also revealed that existing information was not being used to the fullest extent. The first stage of the research work was nearing completion in the middle of last year and it was thought desirable to discuss results at an informal Symposium with organizations concerned with the protection of plant against explosions. The Symposium was, designed to serve two objects, firstly, to discuss the practical value of the work already carried out by the Joint Fire Research Organization and to obtain informed comment and criticism before the next stage of the work was planned and secondly, to put on record general principles on the use of flame arresters and relief vents for the guidance of engineers engaged in their installation. It was intended in the first instance to hold the Symposium on one day, but owing to the large number of intended participants, similar Symposia were held on two days, 19th and 20th November, 1959, for two different groups of participants. In both groups the participants were widely drawn from industry, Government departments interested in safety and the universities. On both days sessions were allocated to discussion, and demonstrations of the experimental work in progress at the Joint Fire Research Organization. Because of the wide interest shown in the subjects under discussion both at the Symposia and subsequently by industrial concerns who were not represented, the proceedings of the Symposia are presented in this note which contains the papers presented by members of the staff of the Joint Fire Research Organization and also an account of the discussion that took place.