Fast Flow Extinguishers
Encyclopedia
Commonly referred to as "Fast Flow" or "High Performance" extinguishers. Available in 13.2 lb (6 kg)., 20 lb (9.1 kg)., and 30 lb (13.6 kg). capacities and contain ABC Dry Chemical
ABC Dry Chemical
ABC or multi-purpose dry chemical is a dry chemical extinguishing agent. It uses a specially fluidized and siliconized monoammonium phosphate powder. ABC dry chemical is usually a mix of monoammonium phosphate and ammonium sulfate, the former being the active one. The mix between the two agents is...

, Purple-K
Purple-K
Purple-K is a dry-chemical fire suppression agent used in some dry powder fire extinguishers. It is the most effective dry chemical in fighting class B fires, and can be used against some energized electrical equipment fires...

, or sodium bicarbonate
Sodium bicarbonate
Sodium bicarbonate or sodium hydrogen carbonate is the chemical compound with the formula Na HCO3. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda . The natural mineral form is...

. They are currently manufactured by Ansul in cartridge-operated form and Amerex in stored pressure design.

UL Rating Differences for "Fast Flow"

These extinguishers have a higher dry chemical flow rate then conventional extinguishers. In other words a fast flow extinguisher expels a higher volume of agent in less time than a standard compliance flow extinguisher. As a result fast flow extinguishers have lower UL
UL
Ul may refer to:* Ul , a lunar deity in Vanuatuan mythology* Ul , a Portuguese freguesia in the Oliveira de Azemeis municipality* 3271 Ul, an asteroidUL may also refer to:* Underwriters Laboratories, U.S...

 class A&B ratings than compliance flow extinguishers(the class B numerical rating is the approximate square feet of burning fuel a novice
Novice
A novice is a person or creature who is new to a field or activity. The term is most commonly applied in religion and sports.-Buddhism:In many Buddhist orders, a man or woman who intends to take ordination must first become a novice, adopting part of the monastic code indicated in the vinaya and...

operator could expect to extinguish). UL Class B tests are conducted on fuel in depth fires in what is known as a burn pan. Burn pans come in various
sizes (square feet) in relation to what UL rating an extinguisher will receive for successfully extinguishing it. The larger the burn pan fire, the larger the rating and the longer the extinguisher must discharge to be able to handle the larger volume of fire before running out. For a given size extinguisher the resulting effect is a lower flow rate, resulting in a higher UL rating.

Generally for same size extinguishers (agent capacity)
  • High UL rating = Low flow rate

  • Low UL rating = High flow rate

Examples

  • A 20 lb (9.1 kg). ABC Compliance flow has a UL rating of 20A, 120 BC.
  • A 20 lb (9.1 kg). ABC Fast Flow has a UL rating of 4A, 40 BC.

Fast Flows and the NFPA

In the revised NFPA 10 section "2-3 "Application for Specific Hazards" requires "fast flow" extinguishers in locations containing pressurized flammable liquids and pressurized flammable gas And areas with three dimensional class B hazards. Pressurized gas and three dimensional fires require higher flow rates then standard extinguishers in order to be extinguished. The higher flow rate puts more agent onto the fire quicker and results in in a faster "knock-down" of the fire. Higher flow rates also provide more operator protection by putting a "heavier" stream of dry chemical in between the operator and fire. This creates a temporary "heat shield" as long as the agent is being discharged because of the light color of the agent it reflects most of the radiant heat back away from the operator.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK