Responded to priority service call for portable fire extinguishers. Inspected 10 ABC dry chemical extinguishers and 2 Class K wet chemical units. Performed visual inspection, checking for physical damage, corrosion, and tamper seals. Verified proper pressure using certified gauges. Conducted 6-year internal maintenance on 3 units due for service. Removed powder, inspected valve assemblies, and replaced O-rings. Refilled with Ansul FORAY dry chemical agent. Updated inspection tags and logged service in NFPA 10 compliant software. Replaced one extinguisher failing hydrostatic test with Amerex B456 6kg ABC unit. All extinguishers now compliant with NFPA 10 standards.