CO129-614-1 Commission of Inquiry into fire at West Point- report 26-5-1949 - 22-12-1949 — Page 85

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would certainly soften the iron sufficiently for the purpose.

3. General picture of the fire, from the technical standpoint.

This section of the report must remain, of course, largely con- jectural, as I was not present during the carly stages of the fire itself. It seems,

however, that some attempt at correlation of the godown con- terts with the effects of the fire would not be altogether without value.

(a)

The fire appears to have taken place in four phases, as follows:

Preliminary small fire.

Explosion.

Period of flaming of film.

Burning of remainder of commodities

(including No. 2 Godown stock).

These will be considered in turn.

Preliminary small fire.

At this stage the cause of the outbreak will not be dealt with. The preliminary small fire observed, which gave a tongue of flame lick- ing out of the grating in the wall of No. 363 above the film stack, is now believed to have been the first drum of film burning.

At any rate, in the space between stack No. 52 and the ceiling, flames were present at this phase. The remaining drums of film would thus be quickly heated; that is to say, those on the top layer of the stack.

Now nitrate film, when heated in closed vessels, instantly starts to decompose by the so-called "flameless decomposition", or "puff- ing". A large amount of gas, mostly inflammable, is evolved, and the reaction proceeds very quickly.

A high pressure is thus developed in the drums in a very short time, resulting in the forcing up of their lids. This brings us to:

(b)

Explosion.

This vapour forms an explosive mixture with air. It would not all burn immediately on evolution from the drums, owing to the limited supply of air in the space above stack 52, and some thus diffused around and downwards, where it would mix with fresh air.

When this mixture reached the flame, an explosion occurred in the general area of stacks 49-52. The wall was blown out, and drums and flaming celluloid film were blown backwards into the godown and out into the street, together with some of the rubber.

Such explosions are a usual feature of film and celluloid fires. They are not powerful or brisant, but relatively mild,

Another effect of this explosion was the bulging of the doors; those in Scavenging Lane powerfully, those in Whitty Street only slightly. The explosion would not be powerful enough to blow the bars of the small left-hand window into Scavenging Lane already referred to.

The other godown windows at this end were covered by stacks. It will be noted that the two Scavenging Lane windows near Stack 30 (Flan No. 1) shewed no heavy blasting. The reason for this is the probable pre- sence, at the time, of Stack 30, a large pile of sulphate of ammonia, which covered these windows. The architect in Plan No. 1 has drawn these win- dows too far apart; in actual fact they both lie together behind Stack 30.