Page 26 - Occupational Health & Safety, April 2018

FIRE SAFETY
Taking Control with the Right Flow,
the Right Extinguisher for Class B Fire Suppression
Is your plant prepared for pressurized flammable liquids and pressurized gas fires?
BY SAM BORAAS
Let’s set the scene. Despite an industrial safety team’s most adept practices to manage a pro- pane storage tank, a leak suddenly erupts from a pipe. In a perfect storm of events, a spark fol-
lows. There is ignition. Instantly, there is a fire.
In an ideal scenario, safety team members swiftly respond and take control of this hazard. This team is able to shut off the fuel source and suppress the fire using the right technique and the right equipment. Among their equipment, there is a cartridge-operat- ed portable fire extinguisher designed with the high agent flow rate required to take control of that pres- surized propane fire. More specifically, it’s an extin- guisher in compliance with National Fire Protection Association (NFPA) 10, Standard for Portable Fire
Extinguishers, Subsection 5.5, Selection for Specific Hazards. This mandate establishes the standard for minimum size and flow rate for portable fire extin- guishers used against Class B fires.
Setting Standards to Change Mindsets
Prior to 2007, this specific NFPA 10 standard did not exist in its current language. Earlier editions in- structed safety professionals to follow manufacturers’ recommendations for the best applications of fire ex- tinguishers. Without an industry-wide standard to fol- low, inconsistencies among those recommendations contributed to confusion over what is the best tool for protecting facilities against Class B fire scenarios.
Then, the benchmark was set in 2007. NFPA 10 Subsection 5.5 mandated “large-capacity dry chemi- cal extinguishers of 10 lb (4.54 kg) or greater and a discharge rate of 1 lb/sec (0.45 kg/sec) or more shall be used” for pressurized flammable liquid and gas fires. In addition, this exact mandate was also applied to other Class B fires, specifically three-dimensional and obstacle fire scenarios.
Why High-Flow Extinguishers for
High-Risk Fire Environments?
“The 2007 NFPA 10 mandate has helped to initiate a change in the mindset of safety teams in high-risk en- vironments,” said Dennis D. Brohmer, Johnson Con- trols Senior Applications Specialist. “However, there’s definitely still more work to do in educating teams about how crucial it is to meet this standard. It’s all about what’s best for the people who are on the front lines of these fire hazards and helping to get the right tools in their hands so they have the best opportunity to put out these fires faster.”
An important detail of the propane storage tank fire example is the use of a high-flow, cartridge-oper- ated fire extinguisher to take control of the situation. Industry professionals might ask why high-flow ex- tinguishers like this perform better and are now man- dated in high-risk environments with flammable liq- uids or gases. This is a common question, particularly in the misconceptions that exist around UL-ratings.
The greater effectiveness of high-flow fire extin- guishers comes down to speed and flow rate. NFPA 10 addresses and standardizes this essential feature directly—i.e., the requirement for a minimum one
20 Occupational Health & Safety | APRIL 2018
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