Every 30 days a fire extinguisher is required to be given an inspection or "quick check" to be sure that it is accessible and will operate. This means verifying that the extinguisher is in the designated location, has not been operated or tampered with and has not incurred any obvious physical damage that could prevent proper operation. NFPA 10 does not require an engineer or fire inspector for this inspection it can be done by a building owner, occupant or a designated representative.
"Fire extinguishers shall be inspected when initially placed in service and thereafter at approximately 30-day intervals. Fire extinguishers shall be inspected, manually or by electronic monitoring, at more frequent intervals when circumstances require...and shall include a check of at least the following items:
(1) Location in designated place
(2) No obstruction to access or visibility
(3) Operating instructions on nameplate legible and facing outward
(4)* Safety seals and tamper indicators not broken or missing
(5) Fullness determined by weighing or
(6) Examination for obvious physical damage, leakage, or clogged nozzle
(7) Pressure gauge reading or indicator in the operable range or position
(8) Condition of tires, wheels, carriage, hose, and nozzle checked (wheeled units)
(9) HMIS (hazardous materials identification systems) label in place"
-NFPA 10 - 6.2