Flammable Liquid Fire Safety (1956)

[Music] C flammable liquids thousands of gallons stored in huge tanks modern industry uses flammable liquids in tremendous quantities received in tank cars tank trucks and drums manufacturing plant that doesn't use dipping coating spraying as a solvent as fuel or in chemical processes why do we have to handle flammable liquids with such great care let's answer that question by setting up a demonstration to show the tremendous power in a drum of gasoline when gasoline or any other low flash point liquid is ignited it flashes into flame instantly the intense burning produces tremendous heat when this heat affects the other drums something is bound to happen what you see here is the tremendous Power released by only 40 Gall of gasoline the bursting of a single drum you can well imagine what the result would be if this uncontrolled power were released inside the buildings of your plant when flammable liquids become ignited damage and destruction are inevitable unless the danger has been foreseen and unless adequate fire protection has been provided we are now getting ready to set off an explosion in a concrete test tunnel to speed things up we're going to spray gas gasoline over warm bricks explosions can be just as destructive as fire or even more so when the spray hits the warm bricks it vaporizes and forms an explosive mixture with air which fills the entire tunnel one end of the tunnel is a wooden construction inside the explosive mixture is ready to be ignited when an explosive mixture is ignited all the energy is released at once tremendous pressure develops almost instantly and the weakest part of the construction gives way this sort of thing can happen whenever low flash flammable liquids are left exposed so they can vaporize into the air if means are provided for venting serious structural damage will be prevented explosion venting windows for instance saved this building by opening automatically and relieving the pressure pressure but if the pressure is bottled up as it was in the enclosure around this oven destruction is bound to be sudden and complete what are the precautions that we all must keep in mind in dealing with flammable liquids first of all make sure there is no source of ignition That Could set off a fire or explosion a spark or a tiny flame is all that's needed to ignite a flammable liquid of low flash point when the vapors Catch Fire the entire surface flashes into flame wherever flammable liquids might be exposed it's absolutely essential to eliminate any chance of Sparks or flame take smoking for instance the man who ignores the no smoking rule is no friend of yours he risks the safety of the place you work he endangers your job and may even endanger your life a moment of carelessness with a lighted match May mean a lifetime of regret play safe obey the rules don't smoke or use matches in any way in flammable liquid areas static electricity is another common fire cause where flammable liquids or compounds are exposed as for example at spreaders and coating machines how does static electricity occur on a machine like the one we just saw the static is generated where the cloth leaves the rolls let's see what a static spark looks like maybe you remember the machine used to demonstr at static electricity in the laboratory when a sufficient charge is built up a spark jumps across the air gap this is the spark that means trouble when it occurs near flammable liquids now let's run the electrodes from the static machine and hold them over a pan of liquid you're not likely to see the spark when it occurs but there's no question about the result produced what's the answer how can we prevent static Sparks at processes where flammable liquids are handled one way is to humidify the air this puts a thin and invisible film of moisture on all objects which drains away the static as soon as it forms a dangerous charge cannot accumulate another way is to provide electrical grounds so the static will quickly be carried away first the machine frame is grounded then the spreader knife is grounded to the machine frame but we still have to take away the static that forms at the rolls this is done by the use of static neutralizers of which these are three typical examples the neutralizers are placed at the points where the cloth leaves the roll as near to the cloth as possible across the entire width of the cloth and one end is connected to a ground what does this grounding accomplish suppose we attach a ground wire to one of the electrodes from the static machine the machine generates static electricity just as it did before but now we get no spark and no fire the ground wire carries off the static charge so to do your part in preventing static fires if you operate a flammable liquid process examine the grounds frequently and keep them in good condition here is one of the most serious of all ignition sources the Sparks that are given off from cutting and Welding torches you don't need much imagination to guess what will happen when one of these globules comes in contact with a flammable liquid the effect is instantaneous and the consequences may be tremendous if large quantities of liquid are involved in an important manufacturing area let us take a look at only one of the many fire disasters that have been caused by cutting and welding equipment the lesson is clear never use cutting or welding equipment in such a way that a spar can reach and ignite flammable Vapors let's now spill a little gasoline to illustrate another common source of ignition the misuse of electricity when an ordinary electric lamp is used near flammable liquids there is always a chance that it will be broken accidentally even with a wire guard an ordinary lamp can still be broken what you really need is an explosion proof outer Globe so that when the light bulb breaks no fire will result electrical arcs and Sparks for many Source must be avoided and that's why inflammable liquid areas special electrical equipment is needed you cannot rely for safety on the fact that a liquid has a high flash point some of our worst fires have been in heat treating areas where large quench tanks contain hundreds of gallons of oil quench oil does not ignite readily unless it is first heated to its FL FL Point what often happens is that a conveyor gets hung up a red hot part remains partly immersed and the oil heats up soon it catches fire eventually as all the oil becomes heated the fire can become just as intense as if the liquid were gasoline or any other low flash liquid heat from such a fire will Buckle steel work and seriously damage nearby equipment so wherever high flash liquids are heated or might accidentally become heated treat them with the same care as the more easily ignited [Music] liquids these are the vapors given off from a piece of dry ice notice how they are heavier than air settle to the floor and collect in the pit low flash flammable liquids are continually giving off invisible Vapors which act in exactly the same way it is these Vapors not the liquid that ignite and burn this time we will use a piece of waste saturated with gasoline you cannot see the vapers but they are settling to the floor and flowing into the pit just as the dry ice Vapors did when they reach the spark plug fire immediately flashes back to the piece of waste this simple demonstration shows why it is so dangerous to use flammable liquids exposed to the air and how if you do the Unseen Vapors are likely to reach a source of ignition and envelop you in a flash of flame it would be extremely dangerous in a flammable liquid area to permit any Vapors to collect in this demonstration we've provided ventilating outlets at low points connected to exhaust ducts with a fan continually in operation to draw off the vapors as the vapor Laden air is removed it must be replaced with fresh air from intakes located near the ceiling efficient ventilation like this makes certain that the atmosphere will be kept free of any dangerous concentration of vapors when you have to draw gasoline or a solvent from a drum there's a right and a wrong way to do it this is the wrong way let us see what might happen an open container could be easily upset and spill its contents Vapors could ignite from a static spark or any nearby ignition Source always use a safety container it doesn't expose a liquid surface and if upset it will not spill the contents a safety faucet should be used which automatically stops the flow when the hand is taken away static Sparks can be prevented by grounding the drum itself must be grounded and a ground wire must be connected from the drum to The Container into which the liquid is drawn filling safety cans by hand pumping is the best method of all because it eliminates the leaking and drippage that sometimes occurs when faucets are used you cannot use just any kind of container if you want to handle flammable liquid safely be sure to use an approved safety can a strong spring cover keeps it tightly shut when not in use if the can is tipped over accidentally it will not spill its [Music] contents a flame arrester screen in the spout protects the contents from ignition An approved bench Can is used in operations that require the washing of small parts let's see how a fire in an approved bench Can compares to one in an ordinary open can the bench Can produces only a slight Flame the ordinary can lets the gasoline burn freely extinguishing the fire in the bench Can is simply a matter of flipping the cover into place if you do any swabbing with a cloth the plunger type is the can to use accidental ignition need cause no concern the fire is feeble and it soon dies [Music] out a larger size of wash can is sometimes used for cleaning or dipping the cover is held open by a fusible Link in case of fire the link melts and the cover drops into position extinguishing the [Music] fire what are the best extinguishing agents to use on a fire in a tank of flammable liquids some extinguishing methods are not only unsuitable but positively dangerous a hose stream for instance makes the fire worse by spreading it the gasoline floats on the water and keeps burning later we'll see that the application of Water by means of automatic sprinklers is not objectionable and is actually essential for good protection the ordinary soda acid extinguisher is also unsuitable for flammable liqu liquids the stream is a water solution and has the same effect as a very small hose stream there are three types of extinguishers that can be used effectively on flammable liquid fires one is foam which spreads a blanket over the burning surface and Smothers the fire another good extinguisher is carbon dioxide which reduces the oxygen content in the air below the point which is necessary for combustion a third extinguisher good for flammable liquid fires is the dry chemical type which discharges a cloud of dry inert powder so remember for flammable liquid fires there are three recommended types foam carbon dioxide and dry chemical many dipping processes involve such large quantities of flammable liquids that portable extinguishers would be of no use fixed piping systems are provided instead they operate automatically or can be turned on by hand take foam for instance here the foam is discharging from a special Outlet mounted at the rim of the tank a few inches above the liquid surface eventually the blanket of foam covers the entire surface and the fire is extinguished carbon dioxide also is used through fixed piping systems for the protection of flammable liquid areas or processes it may be applied directly to tanks by means of special nozzles along the edge or above the tank or it may be used in small rooms or enclosures where the entire space can be flooded with the gas the heat of the fire quickly sets off a detector which operates the automatic dripping mechanism as the inert gas floods the area it cuts off the oxygen supply and the fire goes [Music] out water spray can also be used in pipe systems if the flammable liquid has a high flash point the oil used as an insulating medium in Transformers is an example of a high flash point liquid it is not easily ignited but when an electrical breakdown occurs the intense arcing forces the oil out of the Transformer case and ignites it a fixed system of water spray is the best form of protection for this kind of fire when the water spray goes into action it quickly cools the oil below its flash point and the fire goes out here is one of a number of fires that have started INF flammable liquids and caused Great destruction the question might well be asked how can we prevent fire disasters like this the answer is automatic sprinklers sprinklers are needed over all areas where flammable liquids are used regardless of other types of extinguishing systems here is a fire in a low flash point flammable liquid let's see what happens with the sprinklers in operation the sprinklers can't be expected to extinguish a fire in a low flash liquid but they perform two very important functions first they reduce the intensity of the fire and keep the surroundings cool thus preventing the fire from igniting any combustible material in the vicinity and second they keep the building steel work cool thus preventing buckling and collapse if the process involves a high flash liquid like quench oil we might well have just as intense a fire but in this case the sprinklers will extinguish the fire because the water quickly cools the oil down below its flash point you've seen the great Hazard of flammable liquids you've seen the great destruction they can cause now do your part to safeguard their use remember treat flammable liquids with respect no smoking no matches no open Flames prevent static Sparks No cutting no welding use safe electrical equipment make sure ventilation is operating use safety [Music] containers use the right extinguisher foam CO2 dry chemicals inspect and maintain extinguishing systems make sure automatic sprinklers are ready for action [Music]