What is a Fire Pressure Gauge?

A fire extinguisher pressure gauge (also known as a pressure indicator) is a critical safety device installed on fire extinguishers, used to monitor the operating pressure of the propellant gas (such as nitrogen) or extinguishing agent within the tank in real time. It typically takes the form of a mechanical pointer dial or electronic display, using color grading (green, yellow, or red) to visually indicate whether the fire extinguisher is in normal, usable condition:

Green zone: Normal pressure (usually 1.0-1.4 MPa), indicating the fire extinguisher is safe to use;

Yellow zone: Excessive pressure (possibly due to high temperature or overfilling), posing a potential risk;

Red zone: Insufficient pressure (leakage or failure to refill after use), indicating that fire extinguishing effectiveness cannot be guaranteed.

Precautions:
Quarterly check the pointer to ensure it is zero (when not in use) and the dial for leaks;

Regular calibration (generally annually) is required to prevent errors due to mechanical fatigue;

Protective measures should be taken in winter to prevent ice from damaging internal components.

The pressure gauge senses pressure changes through an internal Bourdon tube or sensor, and its readings directly affect the fire extinguisher's discharge distance and duration. Users should check regularly (recommended once a month). If the pointer deviates from the green zone or the dial glass is cracked, the device should be immediately stopped and sent for inspection. Note: Carbon dioxide fire extinguishers are usually not equipped with a pressure gauge, but the dosage is checked by weighing.