Horizontal fire spread by foam-backed, polypropylene carpet

An eight year old boy was badly injured by a fire in his bedroom in May 2005. He spent his ninth birthday in intensive care and died a month later. This case study discusses a missing link into the pattern of fire development which made it difficult to identify the point of ignition. An absence of burning to the floor and isolated areas of burning seemed incongruous with the general pattern of fire development. Several fire investigation texts suggest that carpet cannot spread fire by itself; those texts that do mention the possibility, do not describe the mechanism in detail, nor what evidence an investigator might expect to see after the fire. Experimentation with samples of carpet gave good insight into the mechanism and its effects, thereby providing the missing link by which to connect the areas of burning and identify the point of origin. If elements of the mechanism described in this paper are known, a reader could discern enough from the many papers available to support a working hypothesis but as yet, there is no single paper that describes the phenomenon mechanistically from start to finish, especially to those who have not encountered elements of it before; hence, this paper presents some novel findings. The test involved polypropylene fibre carpets with integral polyurethane foam underlay, a very common type of carpet owing to its low cost and high durability. This is, therefore, an important mechanism of fire spread for fire investigators to be aware of and to understand. As this is a case study, rather than a research paper, the matters are dealt with empirically so the author cautions that when considering this mechanism in a new matter, the investigator should make their own tests of its validity.