Tar Fires—More Smoke than Flame
As with Crude Oil, a Small Fire Makes a Great Deal of Smoke—Usual Methods of Procedure
THE average tar fire does not represent a big problem to a fire department, particularly where modern equipment is at hand. To the spectator, a tar fire may appear to be of tremendous proportions due to the great volumes of smoke commonly thrown off, but to experienced fire fighters a different story is told.
Most tar encountered in industries is made from coal. It is a black, viscous liquid, commonly shipped in tank cars and barrels, and stored either in tanks or in barrels.
It is used for waterproofing, paints, pipe coating, roads, roofing, insulation, production of benzol, toluol, phenol, lampblack and pitch, by distillation; it is also used in the manufacture of medicine.
When afire, tanks of coal tar are much easier to handle than are tanks of gasoline, kerosene or even crude oil. There is less danger of boil-overs, where streams are kept away from the burning tanks of tar, than is the case with crude oil, which may possess considerable water in itself.
But if water streams are thrown into burning tanks of tar. the tar will foam over very quickly, and carry the fire down the outside of the tank.
While intense heat is generated at tar fires, there is very little danger of explosion. If the tar is in cauldrons and if there is open fire beneath, there is always a possibility of the tar becoming ignited and boiling over and reaching the open fire beneath. But even in this case the danger of fire is comparatively mild if the building enclosing the cauldrons is of fireproof construction and if proper equipment is available for handling the blaze.
Empty tar barrels make a very hot fire, and one which is comparatively hard to extinguish due to the fact the tar within the barrels may be burning and it may be impossible to reach the insides of the barrels with streams.
In operating at a fire of this type about the only thing the department can do is to spray over the barrels thoroughly, wetting down the outsides, and then overhauling as rapidly as possible, extinguishing the inside fire as the department progresses.
In the case of cauldrons or vats taking fire, the most practical way of extinguishing the fire is to cover over the vats with sheet iron or similar coverings. The fire is quickly snuffed out by this process. Waterproof covers, wet burlap, oilcloth or similar materials may be used for snuffing out a fire in this manner. It is only necessary to stretch the covering over the cauldron or vat and in this way exclude the air from the zone of combustion. The fire is thereby automatically extinguished.
In the case of large tanks of tar, the task is not quite so easy, for it necessitates extinguishing the fire by the use of foam equipment if such is available.
Foam is discharged over the surface of the tar as in the case of the oil fire, the foam flowing from one side of the tank across and smothering as it proceeds.
The handling of fires in flowing tar, or fires in tar spread over an open area, requires either foam or sand, sawdust or similar material. Water cannot he used in this operation because it carries the burning tar from point to point. Sand covers the burning tar, and thus extinguishes the fire. Sawdust works in a similar manner and is particularly effective if mixed with dry soda. The soda, upon being heated, releases carbon dioxide gas, which, retained by sawdust, forms a blanket over the surface of the burning tar.
If the burning area is small, burlap, wet gunny sacks or similar articles may be spread over the burning surface to extinguish the fire.
Compared with oil fires, the tar fire is an easy task for the average department. The chief precaution to take is to protect men against the flow of burning tar in the event that vats, tanks or other containers open-up during the fire, or in case they boil-over.