The Fire Brigades' Conference
Page 50
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Résumé of a Paper on Fire Hazards Read By A. M. Cameron, B.Sc., before the Annual Conference of the Professional Fire Brigades Association at Edinburgh
lUTUCH of the paper entitled "Some Thoughts on the 1V1Systematic Consideration of Fire Hazard Problems," by Mr. A. M. Cameron, B.Sc., is devoted to general matters, but there are certain points which should be of special interest to our readers. The first concerns the handling of inflammable liquids, and the author points out -that the ignition of vapours from these is still a major source of fires.
It is not always realized how small a quantity is necessary to carburet a given volume of air, nor is it often appreciated how the dense vapours of hydrocarbons will travel through the airlike a 'river, without mixing with it. The ignition point of a rich mixture is low, and there is danger of igniticin from the use of hot rivets. Dropped tools have often been known to• cause a spark sufficient to ignite vapour, whilst the hazard from broken electric bulbs need not be stressed.
Where liquids such as petrol are handled, care should be taken to avoid sumps around the fixtures of pipe-line connections. as it is difficult to avoid some spillage when uncoupling. Of the two evils it is better to spill some on the ground, where it soon evaporates, than to trap a quantity in an open box-like receptacle, where it will remain for some time.
Industrial users of volatile hydrocarbons should be sure that they have some knowledge of the flash point of the liquids they are using.
The toxicity of petrol and benzole vapours is sometimes overlooked. The use of non-inflammable liquids as solvents is spreading, which is much to the good. It may not be out of place to add a note of warning regarding the danger of diluting these liquids with petrol and imagining that the mixture is safe, simply because certain non-flam liquids are used as fire extinguishers. A very large percentage of the non-flam liquid is necessary to render the resulting mixture of vapour non-ignitable.
Dealing with receptacles, it is pointed out that the rapid spread of a fire involving some given substance, or its re, latively easy extinction, depends, to a large extent, on the nature of the containers. This is due not only to the fire-resisting or non-resisting property of the container, but also to its shape. As an example, the author refers to oil products.
These, being stored in tanks usually cylindrical vertically and flat horizontally, permit of extinguishing agents being rapidly projected on to the oil, the burning surface of which is restricted in area. Probably more success has attended the tackling of the extinction of oil fires than in the case of any other type. This is mainly due to the oils being contained in receptacles that lend themselves to successful attack. There is much greater difficulty where oil is spread over a large and uneven surface, or even when stored in horizontal tanks.
Many special extinguishing devices are on the market for dealing with specified types of fire. If a fire chief knows that in his area fires of a certain class are likely to break out, it may become worth while for the brigade to be equipped with the requisite devices.
Other papers read yesterday were Gas Method of Fire Extinction," by Mr. G. Lambert, and "Fire Detection Systems, Their Virtues and Vices," by Mr. R. L. Granville Johnston.
To-day's three subjects are :—" Fire Engineering Hydraulics," by Mr. J. Bowman; "Salvage Corps Work at Fires," by Supt. W. J. Blyth, and "Ambulance Construction and Equipment,' by Mr. A. Lomas. Additional interest is afforded conference members by an exhibition of manufacturers' appliances.