We easily see fire extinguishers everywhere, from buildings, apartments, houses, offices, schools, hospitals, etc. And those places are often equipped with the two most common types of fire extinguishers. It is a dry powder fire extinguisher and a CO2 extinguisher. So how do we distinguish and use these two types of jars?
1. Distinguish dry powder fire extinguishers and CO2 extinguishers:
To distinguish these two types of vases, we can classify them based on appearance characteristics.
First, it can be distinguished by the label on the bottle.
- On the CO2 tank, there are usually symbols MT3, MT5. These are symbols specific to CO2 cylinders. In which, MT refers to the fire extinguishing chemical contained in the tank, which is CO2. The number accompanying the symbol MT is used to represent the volume of CO2 compressed in the tank. This mass does not include the weight of the shell. For example, the fire extinguisher you are using has the MT3 symbol, which means that your extinguisher is CO2 gas and the volume of compressed air in the tank is 3kg.
- On the powder tank with the symbol MFZ: the fire extinguisher has N2 propellant gas that is directly charged into the powder container.
The second visual feature is that the neck of the dry powder bottle has a pressure gauge and the CO2 tank has no gauge.
The third feature is based on the sprayer, the dry powder sprayer is soft and small, and for the CO2 tank, the speaker is big and hard.
2. Fire fighting mechanism:
Regarding the fire fighting mechanism, the dry powder cylinder uses pressure, pushes the dry powder out, isolates the oxygen from the burning material but does not completely extinguish it and the risk of re-burning for solids. The CO2 tank is compressed air. When sprayed, CO2 gas is ejected, cooled suddenly and extinguished the fire, but not completely extinguished and there is a risk of re-ignition for solids.
3. Steps to use a fire extinguisher:
3.1.Steps to use a dry powder fire extinguisher:
To use the dry powder jar, there are 4 steps.
- Step 1, check the pressure gauge. The level is green, the pressure in the tank is good. If the level indicator is yellow, it means that the tank is overpressure, there is a risk of explosion, this is very rare. If the level indicator is red, it means the pressure in the tank is low. If the needle goes down again, the end of the red area means that the tank has run out of pressure and can’t fight the fire anymore.
- Step 2: Shake the jar. In a stationary state, the substance inside the vessel divides into two layers. The upper part is nitrogen gas, the lower part is dry powder. The dominant hand holds the speculum, the other hand holds the bottom of the bottle, shakes the shock 3-5 times.
- Step 3: Unscrew the safety pin. The left hand is placed on the neck of the bottle, the other hand, the index finger is on the safety pin, jerking firmly and decisively. Note, the left hand is placed on the neck of the bottle, absolutely do not hold the speculum. Because when we squeeze the speculum, we are locking the latch, we can’t pull out the safety pin.
- Step 4: Extinguish the fire. One hand holds close to the nozzle. Note: do not handle the nozzle wire or the nozzle tip. Because when holding these parts, the pressure causes the nozzle to rotate, resulting in ineffective fire fighting. Hold the nozzle close to the nozzle, point the nozzle at the center of the fire. Stand 1.5-2m away from the fire, squeeze the speculum with the other hand, until the fire goes out.
Powder pots should not be used in places with modern machinery, equipment and kitchens. Because the powder in the dry powder jar is highly oxidizing and corrosive. May cause damage to equipment. Food, food and water sources that have been contaminated with fire extinguishing powder cannot be used anymore.
3.2. Steps to use a CO2 fire extinguisher:
When using a CO2 tank there are fewer steps than with a powder bottle, but the danger of using a CO2 tank is higher than with a powder one. Because the cold gas when sprayed from the CO2 tank is -79 degrees Celsius. If when fighting a fire, holding the spray speaker, or holding the nozzle will cause frostbite, very dangerous skin necrosis.
The following are guidelines for safe use of CO2 cylinders:
- Step 1: Raise the spray speaker to 90 degrees
- Step 2: Unscrew the safety pin. The procedure for removing the safety pin is exactly the same as for the powder jar. The left hand is placed on the neck of the bottle, the other hand, the index finger is on the safety pin, jerking firmly and decisively.
- Step 3: Extinguish the fire. The dominant hand holds the speculum, the other hand holds the bottom of the jar. Only the loudspeaker sprays at the center of the fire. Stand 1.5-2m away from the fire, squeeze the speculum with the other hand, until the fire goes out.
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