"Stored pressure ABC extinguishers are very common, and they often require internal maintenance every 6 years and hydrostatic testing every 12 years. Other type

"Stored pressure ABC extinguishers are very common, and they often require internal maintenance every 6 years and hydrostatic testing every 12 years. Other types of extinguishers may vary in their internal examination and testing intervals." -https://www.cintas.com/fire-protection-services/fire-extinguishers.aspx https://www.cintas.com/fire-protection-services/fire-extingu...