Six years from the manufacture date or hydrostatic test date, all stored-pressure type fire extinguishers that require a twelve year hydrostatic test must be emptied and are subject to recharge according to procedures outlined under "Recharging" and a thorough internal and external inspection. Upon completion, a Six Year Maintenance label is affixed to the side or rear of the extinguisher cylinder, indicating the month and year service was performed.

Following the recharge process, the extinguisher is inspected according to the procedures outlined under Annual Certification