Extinguisher Valve Stems are Critical Components

By Mark Conroy

A valve stem is an integral part of the extinguisher valve. When the operating lever is pressed, the valve stem is moved downward and allows extinguishing agent to be discharged. Releasing the operating lever allows the internal spring to automatically reseat the valve stem, causing the flow of agent to cease. In general terms, all extinguisher valve assemblies include the valve body, valve stem, internal spring, operating lever, and carrying handle. Of these components, the valve stem is the most frequently replaced. This is done at the time of tear-down, hydrostatic test, or when there is damage or leakage. The service manuals provide information on when to replace them and which ones to use.

Although valve stems serve the same purpose, only the correct one will work properly in each extinguisher. This means having a supply of valve stems available for each extinguisher model. The following tables show common valve stems that are to be used in many handheld extinguishers. Other valve stems for less common models are also available from Brooks.

It is critical to install the correct valve stem in each extinguisher, so it makes sense to have the right ones readily available. Your knowledge of valve stems improves safety, eliminates leakers, and makes the extinguishers ready to use in a fire emergency.

Mark Conroy is an engineer in our Boston, MA office and a member of the NFPA 96 Technical Committee on Portable Fire Extinguishers.Copyright © 2016, all rights reserved.

Disclaimer: The opinions expressed in the above Tech Series article are the author’s only and provide limited information. Although the information is believed to be reliable, Brooks Equipment ® Company, LLC expressly disclaims any warranty with respect to the information and any liability for errors or omissions. The user of this article or the product(s) is responsible for verifying the information’s accuracy from all available sources, including the product manufacturer. The authority having jurisdiction should be contacted for code interpretations.