What indicates that a fire extinguisher needs to be recharged?

A dropped pressure gauge reading indicates that a fire extinguisher needs to be recharged because the pressure gauge is designed to show whether the extinguisher is fully charged and ready for use. When the gauge falls below the designated range, it signifies that the pressure within the extinguisher has decreased, which can result from leakage or the use of the extinguisher. Maintaining proper pressure is critical for ensuring effective operation during a fire emergency, hence a dropped reading warrants immediate recharging or servicing.

Other indicators such as visible corrosion or a full weight may not directly relate to the performance of the extinguisher in terms of its readiness to operate, while a clear inspection tag demonstrates that the extinguisher has been checked but doesn’t reflect the current state of charge.