Manufacturing standard : GB4351. 1 - 2005 “Portable fire extinguishers - Part 1 :Performance and construction”. Testing standard : GB/t 4351. 3-2005 “Portable fire extinguishers - Part 3 :Regulations”. Inspection frequency : 1. Storage for 5 years, 2. Pressure Gauge in red zone, or storage for 3 years . Any situation , the fire extinguisher must be inspected by qualified producer and refilled (2. 1MPa hydraulic teat before refilling).