The experienced laboratory fire technicians are expected to extinguish Class B fires that are 21/2 times as large as a novice user. The UL 711 test fires are 21/2 ft2 for 1-B and 50 ft2 for 20-B. So an extinguisher with a rating of 1-B means the average person can extinguish one square foot of Class B fire.
With this information, you should feel confident that you understand extinguisher ratings. And with this knowledge and an understanding of NFPA 10, your customers can rest assured that you have installed the correct extinguishers for building protection
and hazards in each area. That means they can grab the nearest extinguisher and use it with confidence in the event of a fire.
Click Here to view a PDF version
Mark Conroy is an engineer in our Boston, MA office and a member of the NFPA 10 Technical Committee. © 2017 Brooks Equipment.
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.