CO2 gas extinguisher
This gas has long been used as a fire retardant gas in fixed automatic devices.
CO2 gas has the following properties:
It is a non-flammable gas, odorless, neutral, non-toxic, does not cause corruption, is not a conductor of electricity, its weight is one and a half times that of air, and therefore, when extinguished, it somehow covers the surface of the fire and replaces oxygen. It is done well.
The volume of the extinguishing cylinder contains CO2 gas, which is liquefied at a pressure of about 60-55 atmospheres (900-800 PSI) and is placed in the cylinder. There is empty space for the gas to expand, because the extinguishing body has to withstand a lot of pressure, so it is made in one piece and seamlessly. If it is made of steel, its total weight is increased, but if it is made of aluminum, its weight will be relatively less.
Manual versions of this extinguisher are manufactured with capacities of 1 to 6 kg (12-2 lbs). In most capacities, it is designed and used in the form of wheeled or fixed automatic devices.
Because CO2 does not leave any trace at the point of consumption, it is mostly used indoors and to extinguish Class B and C fires, electrical devices, computer devices, and electrical appliances in general. These extinguishers are usually controllable, the CO2 extinguisher nozzle is in the form of a funnel or horn, and the reason is that it prevents the gas from speeding up as it exits, allowing it to expand, and also preventing loud noise.
It should be noted that one pound of liquefied CO2 gas is produced if 8 cubic feet of gas are released. Although carbon dioxide is not toxic, when used indoors in large quantities, it reduces the amount of oxygen in the air, and anyone in the area will be deprived of oxygen, resulting in suffocation.
If for any reason the internal pressure of the cylinder increases, the safety valve inside which there is a ruptured disc will operate and all the gas in the cylinder will be drained. The resistance of this disk is about 180 atmospheres (2700 PSI), so the CO2 extinguishing cylinder should not be placed in direct sunlight or in the vicinity of heating devices. The body of this type of extinguisher must be able to withstand a pressure of 450 atmospheres (PSI 7000).
To work with this type of extinguisher, first grab the handle and pull out the pin, then press the lever and pour the gas on the fire. Care should be taken that the organs do not come into contact with the discharge horn as this part may cause burns at the site of contact due to excessive cold.
The valve mechanism of this extinguisher must be such that it opens and closes quickly, otherwise the gas turns to ice and blocks the outlet, therefore, valves with a very small outlet are used in this device. The discharge rate of this extinguisher is 95% and its maximum throw is 2 meters. The discharge time of this extinguisher is a maximum of 20 seconds.
Periodic tests: Once every six months, make sure the device is intact, including rust, impact, nozzle and pipe damage, and valve safety. The extinguisher is then weighed and recharged if more than 10% of the gas weight inside the cylinder is reduced.