Standard for Portable Fire Extinguishers

NFPA 10 requires that all portable fire extinguishers be visually inspected at least once per month. Monthly inspections can be performed by building staff and do not require a licensed fire protection contractor, though the inspector must know what to look for.

During the monthly inspection, the inspector verifies that each extinguisher is in its designated location, that it is visible and accessible (not blocked by storage or equipment), that the operating instructions are legible and facing outward, that the pressure gauge shows adequate charge (needle in the green zone), that the safety seal and tamper indicator are intact, and that the extinguisher has not been damaged, corroded, or is leaking.

Monthly inspection results should be documented, typically by initialing and dating a tag attached to the extinguisher. While some building owners treat monthly inspections as a formality, they serve a critical purpose: identifying extinguishers that have been moved, discharged, damaged, or tampered with before they are needed in an emergency.

Annual maintenance must be performed by a trained person who has undergone the instructions necessary to perform maintenance on portable fire extinguishers. Most AHJs interpret this as requiring a licensed fire extinguisher service company. Annual maintenance goes beyond the monthly visual inspection to include a thorough examination of the mechanical parts, extinguishing agent, and expelling means.

For stored-pressure extinguishers, the technician checks the condition of the hose, nozzle, and handle, verifies the gauge accuracy, and examines the cylinder for damage or corrosion. For cartridge-operated extinguishers, the technician removes the extinguishing agent, inspects the cartridge for weight and corrosion, and verifies the agent is the correct type and quantity.

Each extinguisher that passes annual maintenance receives a new service tag or label showing the date of service, the name of the servicing company, and the technician's name or initials. Extinguishers that fail maintenance must be repaired, recharged, or replaced before being returned to service.

Every six years from the date of manufacture, stored-pressure fire extinguishers that require a 12-year hydrostatic test must undergo an internal examination. This is commonly referred to as the "6-year teardown" or "6-year maintenance." During this procedure, the extinguisher is completely depressurized, the agent is removed, and the interior of the cylinder is inspected for corrosion, pitting, or other damage that could compromise its structural integrity.

The valve, stem, and internal components are inspected and replaced if necessary. The extinguishing agent is examined and replaced if it has degraded. The extinguisher is then reassembled, recharged, and re-pressurized. A new 6-year maintenance label or verification-of-service collar is installed on the neck of the cylinder to indicate when this maintenance was performed.

This requirement applies to ABC dry chemical, regular dry chemical, and halotron extinguishers in stored-pressure configurations. It does not apply to non-rechargeable (disposable) extinguishers, which must be removed from service 12 years from the date of manufacture.

Every 12 years from the date of manufacture (and every 12 years thereafter), rechargeable fire extinguisher cylinders must undergo a hydrostatic pressure test. This test verifies the structural integrity of the cylinder by pressurizing it with water to a test pressure significantly higher than normal operating pressure. A cylinder that fails the test — showing permanent expansion beyond acceptable limits, leakage, or visible deformation — must be condemned and destroyed.

The hydrostatic test must be performed by a facility or person meeting the requirements of the standard, using calibrated test equipment. The test date and the name of the testing facility are stamped or labeled on the cylinder. Extinguishers in service beyond 12 years that have not been hydrostatically tested must be removed from service immediately.

Carbon dioxide (CO2) extinguishers have a shorter hydrostatic test interval of 5 years due to the higher operating pressures involved. Water and wet chemical extinguishers also require 5-year hydrostatic testing. Always check the specific interval for the type of extinguisher in your building.