At which position of the pressure gauge pointer is the pressure normal for a fire extinguisher?
3 Answers
The pressure of a fire extinguisher is normal when the pressure gauge pointer is in the green zone, with the normal pressure value typically ranging between 1.2—1.5 MPa. If the pointer is in the red zone, it indicates insufficient pressure inside the cylinder, meaning the fire extinguisher cannot be used normally. If the pointer is in the yellow zone, it indicates overpressure, which can be dangerous (though slight overpressure may still be considered normal). Here is some additional information: 1. Combustion Reaction: Fire is a chemical combustion reaction, usually caused by the reaction between oxygen in the air and certain fuels such as wood or gasoline. Of course, wood and gasoline do not spontaneously combust simply by coming into contact with oxygen; combustion reactions only occur when the fuel is heated to its ignition temperature. 2. Introduction to Fire Extinguishers: A fire extinguisher, also known as a fire canister, is a portable firefighting tool. It contains chemicals designed to extinguish fires. The fire extinguisher consists of a sturdy metal cylinder filled with water or fire-extinguishing materials. When the lever at the top of the cylinder is pressed, the high pressure generated forces the extinguishing agent out of the cylinder, similar to how aerosol cans spray materials. The function of a fire extinguisher is to displace air, depriving the fire of oxygen and extinguishing it. Since carbon dioxide is a gas and leaves no residue, it is used to extinguish fires without damaging equipment.
The fire extinguisher in a car is very important, and I always check the pressure gauge regularly. The pointer in the green zone indicates normal pressure, meaning it’s safe to use. The red zone means insufficient pressure, and the extinguisher may not discharge properly; the yellow zone indicates excessive pressure, which can be dangerous when used. I take a quick look every time I wash or service the car—safety comes first, after all. Long storage or extreme temperature changes can affect the pressure, so extra attention is needed in winter and summer. There’s a small circle on the extinguisher with green paint inside—if the pointer stays entirely within it, everything is fine. If it drifts into other colored zones, it’s best to replace it immediately or have it refilled at a professional shop.
Checking the pressure gauge on a fire extinguisher is actually quite simple. If the needle points to the green zone, it's normal. I didn't understand it before either, but I learned after a minor incident. The red zone indicates the pressure is too low, while yellow means the pressure is too high—only the green zone is the safe range. The same rule applies to household fire extinguishers. Every time I refuel or before a long trip, I open the trunk to check, making sure the needle stays firmly in the green area for peace of mind. Older fire extinguishers are prone to pressure leaks, so I inspect mine every three months. The small round gauge at the bottom is easy to recognize, divided into three colored sections with green in the middle. Just remember this—don’t wait until an emergency to find out it’s not working.
