Modern Gasworks Practice

376 MODERN GASWORKS PRACTICE The Fuel Agent of the Canadian Pacific Eailway states that he always recom-mends the use of water if the fire is a small one, and particularly if it is detected in an incipient stage. His practice is to locate the hot spot by driving test rods into the pile and tlien to dig a pit one or two feet deep right over the centre of the trouble ; to drive and pull pointed rods or open pipes from it down into the heating mass and then to fill the pit with water, tlius quenching the fire at its very centre. At the same time, if the fire is a large one be surrounds the whole h.eated part with a water curtain made by digging a ring ditch one or two feet deep and perforating its bottom with a row of holes as in ventilation. This ditch, like the central hole, is kept füll of water from the hose, and if there is any tendency for the fire to be driven outward from the centre, it is quenched by the water curtain. This metliod of putting out a fire is of course costly, but it is enormously quicker and less costly than that of digging out and results in far less loss of material. Dealing with Wet Coal That damp coal has an undesirable effect when carbonized in ordinary horizontal retorts is indisputable. In works in which there are chamber-ovens or vertical retorts, the moisture matters but little. Accordingly, the dry coal could be reserved for the horizontal house, while the wet coal could be disposed of in the verticals. For some unexplained reason, certain coals prove themselves particularly liable to spon-taneous combustion when tinder a covering of snow. Occasionally fires have been caused by hot pipes which run through the heap or under the ground upon which the coal is stacked. Thiis it appears that a very small source of external heat is sufficient to start the action, especially if the heat is local and applied towards the centre of the mass. Another point is that of the local application of water. While a shower of rain seems to have little effect, a stream of water confined to one small area will probably cause a rise in temperature. This is best illustrated by the case of the covered coal store with a leaky roof, and the faet that fires frequently occur direetly under the leak. Leaky water-pipes in the vicinity of the heap very often lead to trouble. Finally, for the prevention of heating, and for the treatment of fires, the author suggests the following points :— 1. Stock different types of coal in separate heaps. 2. Surface ventilation only. 3. Mix lumps and fine together. Small heaps are less dangerous than large ones. 4. Do not pile to a greater height than 20 feet. 5. Avoid external sources of heat, such as hot pipes. 6. Ättend to leaky water-pipes or gutters in the vicinity of the heap. 7. When temperature rises to 35° C., remove top lavers and carefully watch. 8. Do not disturb the fire by pushing in bars, etc., from the side of the heap. 9. Apply water to tlie seat of the trouble only, particularly if fire occurs in confined stores. 10. Remove and carbonize the aflected coal as soon as possible.