What is the normal position for the pressure gauge needle on a fire extinguisher?
2 Answers
The pressure gauge needle of a fire extinguisher is normal when it is in the green zone, with the pressure value typically between 1.2 to 1.5 MPa. When the needle points to the green zone, it indicates that the extinguisher is safe to use. If the needle points to the red zone, it means the pressure inside the cylinder is insufficient, rendering the extinguisher unusable and requiring replacement. When the needle points to the yellow zone, it indicates excessive pressure, which can be dangerous, and the extinguisher should be sent to a specialized agency for inspection and repair. If functional inspection reveals any issues with the fire extinguisher, it must be entrusted to a qualified maintenance unit for repairs, including replacing damaged parts, conducting a hydrostatic test on the cylinder, and refilling the extinguishing agent and propellant gas. The maintenance unit must strictly adhere to the fire extinguisher scrapping policy. Every five years and before each refill, the main pressure-bearing components of the fire extinguisher, such as the head and cylinder, must undergo a hydrostatic test. Only those that pass the test can continue to be used. After testing, the extinguisher should be promptly dried, and the inner wall should be inspected for any significant corrosion. If the hydrostatic test fails, the extinguisher must not be repaired using methods such as welding and should not be used.
After driving for so many years, the pressure gauge needle of the fire extinguisher in my car normally stays firmly in the green zone, which is the safe area indicating the pressure is just right. Green is always good news. If it drifts into the yellow zone, it means the pressure is too high, risking leaks or dangerous expansion. If it jumps to the red zone, it’s even worse—the pressure is too low, rendering it useless and unable to discharge. I make it a habit to check it every quarter, like taking a quick look while washing the car, ensuring the needle stays steady in the green zone without wobbling. Remember, don’t ignore a drifting needle. Once, my neighbor’s fire extinguisher had its needle in the red zone, and when an engine fire suddenly broke out, it was useless—thankfully, my green-zone extinguisher saved the day. In terms of maintenance, temperature fluctuations might cause slight needle movements, but as long as it stays centered in the green long-term, it’s fine. If something feels off, replace it—safety first.
