Fire Safety Science Digital Archive

If a piece or pile of self-heating material is heated, for example during a manufacturing process and then exposed to cool surroundings, it may cool down to a stable safe condition or if the cooling is insufficient, heat to ignition. This paper describes the theory of a new, relatively simple, method of discussing such a problem and so finding criteria for specifying the safe initial conditions, i.e. the necessary degree of cooling. Practical applications will be discussed elsewhere. In the special case of a very low surface heat loss one can neglect internal temperature differences and the theoretical treatment is then trivial. When the surface losses are very high the surface temperature is close to the ambient and one can readily adapt published computer solutions to a similar problem arising in explosion theory. The general case has hitherto not been dealt with by any method which is both as simple and, as judged by the two extreme cases, as accurate. The criterion developed relates the critical explosion parameter ? to the excess temperature ?0 and the cooling characteristic of the equivalent inert material.