FIRE LOSS MANAGEMENT
DISASTER MANAGEMENT
Part 9: EXTENSION -MORE ON KNDLING
THE MOST important precaution when handling flammable liquids is to guard against the ignition of vapors. All ignition sources must be removed or isolated from any space where flammable vapors exist. This requires a knowledge of ignition sources including those mentioned before: static electricity, metallic sparks, and open flames. Also vital is knowledge of the vapors’ physical characteristics. Are they heavier or lighter than air? All too often people use flammable solvents and are burned to death when the death cloud reaches the water heater or the pilot light on the stove.
ELECTRICAL HAZARDS
Where flammable vapors might regularly be present, the entire electrical system and its connections must be sparkproof and motors explosionproof. Every electrical device that makes and breaks a circuit provides a spark sufficicnt to ignite an explosive mixture of a gas. Any electrical light fixture that breaks can do the same. Plugging an electrical unit into a receptacle provides a spark sufficient to ignite flammable vapors.
Where explosionproof electrical equipment is provided, the system must be complete. Very often such equipment is provided initially, but later, when new equipment is added, it is not explosionproof, and the safety system is breached. Explosionproof electrical equipment is another case in which half a loaf is worse than none because it provides a false sense of security.
CONTAINERS
While the initial ignition of a flammable liquid is a function of the explosive range and the source of ignition, the volume of fire that develops depends on the quantity of flammable liquid available. For this reason, regulations are less stringent for smaller quantities. Some very volatile flammable materials can be packed in glass bottles as long as the glass bottles hold only a few ounces.
Safety cans listed by Underwriters Laboratories or approved by Factory Mutual laboratories must be used to handle flammable liquid in quantities larger than a few ounces. Some safety features include a rim around the bottom to absorb the impact of hitting the ground, heavy metal, a valve that automatically closes on a spring when released, a flash arrestor inside the spout to prevent transmission of an ignition to the contents, and release devices so the container will not explode if subjected to sufficient heat to raise its internal pressure to the bursting point.
With regard to handling solvents of high chemical purity, some maintain that ordinary safety cans contaminate the contents. This is quite true, but there are safety cans made with a variety of materials and gaskets to handle practically any material. A blitz can similar to those developed for the Allied advancethrough Normandy, a glass bottle, or a tin can painted red are not safety cans.
Many firefighters are unaware of the hazards of flammable liquids. In onecase, a city failed to provide a safety can for generator fuel used by the firedepartment. A firefighter filled a discarded foam can with the proper gas-oil mix for the unit; this was carried on the running board. Invited to ride with the company, I declined until the can was removed. The can was on or off the truck depending on the officer on duty. In another case, one fire company turned out early one morning for a raging gasoline fire in its own basement.
Mishandling flammable liquids has caused serious accidents in training. In World War II, I commanded a Navy firefighting school. Part of the required standard program involved extinguishing a gasoline fire in a structure with fog applicators. Burning gasoline was flowing from holes in pipes arranged like a Christmas tree—actually a man was pumping the gas with a hand pump, and when he stopped pumping, the students were convinced that they had extinguished the fire. This was simply bad teaching. Extinguishing a fire in flowing flammable liquid inside a ship would set up conditions for a massive explosion. At my school the gasoline flowed continuously by gravity, so the fire was legitimately extinguished. After four students were burned, I dropped the exercise from the program.
PURCHASING PROBLEMS
The purchasing department tries to buy materials at the cheapest possible price. The 55-gallon drum price of flammable liquids is much less than that of one-gallon containers, but when the quantity of flammable liquid available is increased, so is the risk. Therefore, the savings achieved by purchasing flammable liquids in larger quantities must be weighed against the risk to personnel. If large quantities of flammable liquid are purchased for economic reasons, adequate, isolated storage facilities should be provided.
Storage and handling of flammable liquids is almost always a source of contention in laboratories and other research facilities. Researchers and laboratory personnel tend to want all necessary flammable liquids immediately at hand. However, labs should have all flammable liquids stored in a safe location—where the maximum credible fire involvement would not destroy the operation. Only the minimum quantities necessary for daily use should be brought into the laboratory.
Gallon bottles of acetone, alcohol, ether, or other highly flammable and dangerous substances are often placed on top of cabinets or shelves totally unprotected and ready to be knocked off, with the potential for creating a death cloud and a tremendous disaster. People say, “It’s only a gallon,” mistakenly believing that one of anything can’t be too bad. To dispel this belief, set up the following demonstration: Drop a gallon of the flammable liquid in use adjacent to a source of ignition. This is best done in at least a partial structure so the foil effect of the fireball can be seen. If clothed dummies are available, add them to the demonstration. Afterward, few will argue that “only a gallon” poses no threat.
(For more information, see NFPA Handbook, 16 Ed., Chapter 4, pages 528. Industrial process systems are covered in Section 10.)
FLAMMABLE GASES
Flammable gases present much the same hazard as flammable liquids. As a matter of fact, gases can be even more serious. As soon as the gas is released from its container, all of the supply is available for ignition. Conversely, in the case of flammable liquids, the evaporation takes place at a faster or slower rate depending on physical and chemical factors. Common flammable gases are liquefied petroleum gases such as butane, propane, hydrogen, acetylene, methane, and natural gas.
Oxygen, of course, is not a flammable gas, but for operational reasons it is often found in conjunction with flammable gases. If the oxygen is released, the rate of combustion is tremendously increased, and oxygen itself can react spontaneously with oil or grease to create an explosive ignition.
Before handling flammable gases, ask yourself this question: If all of this flammable gas were released, would it be dissipated to the atmosphere harmlessly or would an explosive cloud result? If an explosive cloud would result, then there must be absolutely no source of ignition in the area. While this may sound simple, people still continue to take risks if they have yet to create an explosive cloud and bring a portion of this cloud up to ignition temperature. The people who brought the LPG cylinders inside the Indianapolis Colisseum for the hot dog cooker had had, I’m sure, no previous accidents before the LPG blew up and killed more than 60 people.
EMERGENCY SITUATIONS
There have been many cases of disastrous gas explosions involving both liquefied gas containers and gas distribution systems. Various references contain adequate information on the control of gas hazards, but I have not seen a satisfactory discussion of the best procedures to take when approaching a building filled with an explosive gas. This is one of the most serious situations fire departments face. Because the hazard is not evident it is often underestimated, and in many cases the results have been disastrous.
I cannot offer a complete list of precautions that will guarantee no injuries, but laying out system-supplied (not just booster tank) hoselines and wearing full protective gear are vital. In Dayton, Ohio this past year, a fire lieutenant died of injuries he received when he and several other firefighters were hit by an explosion in an apartment house basement. They were investigating a reported gas leak. Five firefighters and two residents were injured.
Think through a plan of action in advance. One fire chief told me of responding to a gasoline station that had a leak. His first order was “turn out the lights.” He though this would prevent customers from driving into the station and complicating the problem. I pointed out that turning out the lights was as bad as turning on the lights. Any time you throw an electric switch, you can create an arc. So probably the first action to take is to do nothing until you have thought out your approach to the problem. If you decide to kill the electrical power in the building, kill it at a point where the resultant spark cannot cause ignition. Certainly do not kill it within the building. Killing the power does not remove all sources of ignition—for instance, gas pilot lights.
Attempting to determine the degree of the hazard by using explosive meters may be extremely hazardous to the personnel operating the meters: While the meters themselves are designed not to cause an explosion, the person using the meter may be in the death cloud. On the other hand, the command may well be criticized for taking certain actions that appear to be destructive because the severity of the hazard is not evident.
Regulator valve failures are infrequent, but when they occur the fire department must be quick to size up the situation. Command officers, company officers, and dispatchers must be trained to consider gas system failure if multiple calls are received indicating fires in several dwellings in an area. When a regulator fails, the pressure goes up on every appliance: Pilot flames become jets, and operating stove burners can deliver flames to the ceiling. Massive assistance should be called as soon as this problem is confirmed.
PREPLANNING
Preemergency planning for incidents involving flammable gases is vital, particularly if the risk of the hazard occurring is quite probable. All those in authority should agree to a plan of action and thus accept the responsibility, jointly, for the actions taken.
One fire department has a joint response and operating plan with the local gas utility. However, the gas company authorities do not call the fire department immediately after they are notified—they wait until their crew is available to be dispatched. This leaves the fire units in the foolish position of a screaming response to a situation reported perhaps hours ago. The gas company must understand that evacuation takes precedence over its convenience or its own ability to respond to the call.
When it comes to utility companies in general, never assume that their representatives are expert or careful in their methods. My wife stopped a gas company employee from turning on the gas in our new house when she pointed out that there was no regulator or meter, only an open 1 Vi-inch, highpressure pipe. Fortunately, she knew more about the hazard than the average housewife.
Utilities must coordinate their activities with the fire department. A gas company crew was replacing a regulator valve in a high-rise apartment house. A trailer of gas cylinders was hooked up to the building main as a temporary gas supply. The trailer was hooked to the wrong side of the regulator. All stoves in the “on” position emitted hugh jets of flame and serious fires resulted. Fortunately the alarm was transmitted as soon as the first fire was reported to the gas company’s front desk. In what for a utility company was a remarkable display of public relations acumen, the management simply said, in effect, “We’ll pay for everything, for everybody. Just send us the bills.”
By accepting joint planning responsibility, all deny themselves the right to criticize out of hand the actions taken in accordance with the plan. For instance, using high-expansion foam could be the best way to de-gas a building. The equipment can be set up outside, the generator can be set up far enough away that no fumes will be recycled, and the foam can be used in at least some circumstances to push the gas out. However, due to the emotional impact of filling the place with “soap suds” and the belief that “tremendous damage” might be caused, it would be vitally necessary that this method be planned in advance.
A building containing a mixture of gas and air in or above the explosive range should be treated with as much respect as an unexploded bomb. Why an emergency force should treat a gas-filled building as routine cannot be explained, except on the basis of ignorance.
You should have a complete knowledge of the gas including its toxicity; any other physical or chemical hazards; its explosive range, whether it is w ide or narrow: and whether it is lighter or heavier than air. The old coal gas had a natural odor. Its replacement, natural gas, does not. There was no odor to the natural gas that exploded inside a New London, Texas High School in 1937, killing 294 students and teachers. Natural gas and bottled gas have no natural odor. They are odorized with a chemical that can be filtered out by the earth. A sudden explosion blew up a concrete block wall in a store. The gas had been’ disconnected for some months. A partially filled LPG tank, located in the rear yard, was leaking slightly. The gas followed along the pipe and into the, store—the odor had been filtered out by the earth.
Note that accidents involving gas distribution systems are of concern to the National Transportation Safety Board. It has published a number of valuable reports on serious explosions. If you read some of them, you may be sur-‘ prised at the nonchalance with which gas company personnel sometimes regard gas leaks.
Fighting a fire involving a flammable gas leaking from a container should be undertaken only if the efforts will notworsen the condition. The extinguishment of the flame and the subsequent release of unburned gas may set the stage for an explosion. In any event, however, we should know what extinguishing agent will extinguish a particular gas. For instance, ordinary dry chemical does an excellent job of extinguishing propane gas. A series of propane gas fires can be extinguished with one extinguisher. By contrast, hydrogen gas is extremely difficult to extinguish. Some limited success can be obtained with potassium bicarbonate. In general, the best practice is to allow the gas to burn out, using water spray to protect any exposures, thereby eliminating the potential for creating a death cloud.
A pipeline exploded in Virginia, creating a large crater. Strategically, it was important to extinguish the fire. Dry chemical extinguished the fire, but redhot metal kept reigniting the gas. The crater was then filled with foam, blanketing the hot metal. The gas fire was then extinguished. Flammable gases and liquids are transported by pipelines that crisscross the country like a spider web. If there is a pipeline in your area, you should know all about it.
This is a brief treatment of a most important subject. For more information, see the NFPA Handbook, 16 Ed., Section 5, Chapter 5 and publications on hazardous materials.
