Protection of Detroit Auto Plants
IN Detroit we have approximately 146 automobile and body plants. Some of these plants are eight stories high, 2,170 feet long and cover an area of 71.8 acres. The most essential protection in case of fire is the education received by the officers and men previous to the fire.
Regular inspections are made to familiarize themselves with thousands of dollars worth of fire extinguishing equipment that has been installed. In making these inspections it is required of the firemen to make a sketch of the entire plant, showing the location of stairways and exits, hazards of which there are many: also gas shut-off valves, controls for shutting off electric current, sprinkler systems, gasoline and paint pumps; also fire-walls, windows leading into elevator shafts and all barriers that would retard the raising of ladders, etc., and also to see that good housekeeping conditions prevail.
Sketch is Checked by Blue-Prints
When this inspection is completed and he returns to his quarters, the fireman presents his sketch to his commanding officer. He and the Battalion Chief of the district, who have blue-prints of the plant, make a check to see that they correspond. If they find a difference, the fireman is sent back to the plant until it is rectified. Then they are satisfied he knows the building thoroughly. This inspection differs somewhat from the inspection made by the Fire Prevention Bureau, due to the fact that these are the men that are actually going to be present and work on the fire.
Another means of protection is to fight a supposed fire before it occurs, both at the engine house and at Training School. Here the men are questioned as to what they would do under certain circumstances. For example: they are asked “If a fire occurred in plant 5, of a certain plant, what class of work is done and what materials are carried in Department D. They are then asked the proper extinguishing agency to be used on that type of fire. If it is a Spraybooth where Pyroxylin paints and thinners are involved and has extended to vent ducts, which are large ventilating pipes conveying the fumes out to the atmosphere, in the upper part of the duct there is located an open sprinkler head which is controlled by an automatic valve which is always located in close proximity to the booth. There is also an automatic flood valve that floods the booth with water—water being the proper extinguishing agency for this type of fire.
Handling a Spray Booth Fire
When fire occurs in a spray booth, the flames are forced by the ventilating fan through ducts that extend through the plant several feet before passing through the outside wall, extending upward above the roof. There are often a battery of 12 in a row, only a few feet apart, and the electric fan that is ordinarily used to force the fumes through the duct to the outside atmosphere now forces the intense heat through the same duct, causing it to become a white heat. In a few seconds, naturally, the radiation is intense. However, this type of fire is usually easily extinguished, provided the fan is kept in operation.
After the fire in the booth and duct has been extinguished, due to the large amount of water used, it is apt to short the electric wires attached to the motor that drives the ventilating fan. Precaution must be used to examine all ducts where the radiation of heat may have caused it to start smoldering and in time will create gas and explode. With the ventilating fan system impaired, the fire will then follow the line of least resistance, which would be out through the open booth and would then extend throughout the plant. If the Fire Department should return to its quarters before this was determined, the entire plant would be enveloped.
A cleanout slide is located on the under-side of the ducts, when the fireman opens these slides to determine if they are smoldering, a long plaster-hook is used to pull the slide open. This precaution is used to protect him from being burned. As soon as this slide is opened and oxygen is admitted and comes in contact with the smoldering pyroxylin there usually is an explosion. After a reasonable length of time, if there is no reaction after opening the slide in the duct, it is safe to order the department back to their quarters.
Pyroxylin paint or lacquer is made with some form of nitrated cellulose and pyroxylin cotton commonly known as “gun cotton” base. When burning, the fumes arising are known as nitrate acid gas. When an explosion takes place, either with pyroxylin paint or celluloid, the fine fibres from the gun cotton, which nestles on the lungs of a human is very injurious and often fatal. Therefore, it is recommended where these fumes exist in a small enclosure that gas masks should be worn.
Teamwork Between Fire Department and Plant
It is very essential that proper teamwork and co-operation exists between the city Fire Department, plant fire department or watchman. For example, the fire is discovered and the alarm box is pulled for a certain plant. This plant consists of several buildings covering a large area which necessitates several gateways and driveways. The fire alarm box and annunciator is generally located in the main entrance. If the entire assignment responded to the main building where the annunciator is located to determine the location of the fire, there would follow a congestion of apparatus and a serious delay would result. In most large plants this would not happen, as the men on duty at the different gates of the plant are notified as to the location of the fire, which may be several blocks from the alarm box and annunciator; thus the gateman would direct the apparatus by giving them the exact location of the fire, For example: “Building 5, Department, D.” The officer must not only know the location of Buildings 5, but also Department D, which is on the fifth floor. He must also know the location of the nearest stairway and that the stairway extends to the fifth floor. With that knowledge, it is an easy matter to secure the nearest hydrant and know the required amount of line to reach the fire. If the building is sprinkled the first line is attached to the Siamese connection, 100 lbs. pressure olaced on it, and the second line stretched to the scene of the fire. If a standpipe is available, two lengths of hose, 50 feet long, rolled especially to make it convenient to connect to the standpipe, would be carried to the fourth floor. It is our practice to make the connection on the floor below the fire, so that in case we are forced to retreat, it can be done without sacrificing the hose and gives us a chance to regain lost ground as soon as the opportunity presents itself.
(From a paper read before the Annual Convention of the International Association of Fire Chiefs.)