You can determine if a fire extinguisher is ineffective by checking for the following signs: Age: Fire extinguishers have a limited lifespan, and over time, the pressure inside the cylinder may decrease, making it less effective. The age of the fire extinguisher should be indicated on the label, and if it is more than 5 years old, it may be time to replace it or pressure test. Damage: If a fire extinguisher has been damaged, such as if it has been dropped or exposed to extreme temperatures, it may no longer be effective. Look for signs of dents, cracks, or other damage to the cylinder or the valve. Leakage: If you notice a puddle of fluid around the base of the fire extinguisher, or if the pressure gauge indicates a low pressure, this may be a sign that the fire extinguisher is leaking and is no longer effective. Discharge: If the fire extinguisher has been discharged, but the pressure gauge still indicates that it is full, this may be a sign that the fire extinguisher has not been recharged properly and is no longer effective. Expiration: Some fire extinguishers have a limited lifespan and may become ineffective after a certain period of time, even if they have not been used or damaged. The expiration date should be indicated on the label of the fire extinguisher. If you suspect that a fire extinguisher is ineffective, it should be inspected by a qualified technician, who can determine if it is still safe to use and make any necessary repairs. It is also a good idea to replace any fire extinguishers that are more than 5 years old, or that show signs of wear and tear, to ensure that they are always ready to use in the event of a fire.