Flammable and combustible liquids are liquids that easily ignite and rapidly burn out of control within seconds. The NFPA and OSHA have strict requirements for storing these liquids, and extinguishing fires caused by highly caustic liquids.

Understanding differences in flammable liquids

Each type of flammable liquid has a flash point, which is the minimum temperature at which liquid forms a vapor above its surface in sufficient concentration that it can be ignited. The lower the flash point, the more flammable.

One of the main reasons these liquids are so flammable is the vapor that they emit (and a reason why proper ventilation is so important).

NFPA 30 & OSHA requirements and guidelines

There are many requirements on how flammable and combustible liquids can be stored. From the size of the container to location. Both the NFPA and OSHA have guidelines on the storage of flammable and combustible liquids. NFPA 10 Section is the standard for pressurized flammable liquids and pressurized gas fires.

The hazard classifications for stored flammable liquids is important to consider. You need to know what you’re dealing with in order to understand how to safely extinguish fires caused by these liquids. For this reason, the NFPA has assigned a “Class” for each type of liquid, based on their boiling point and flash point.

 UC San Diego complied a helpful chart to illustrate the various classifications for flammable liquids:

flammable liquids

As you can see in the chart, there’s a lot of difference in the flash point for motor oil and mineral oil, for example. You would need to use a portable fire extinguisher intended for that class of flammable liquids.

High Flow Fire Extinguisher

Not all portable fire extinguishers are effective in extinguishing fires caused by flammable liquids. You must use a fire extinguisher approved for Class B and C fires, such as a high flow fire extinguisher.

A high flow fire extinguisher has twice the flow rate of standard fire extinguishers. These portable fire extinguishers are intended for applications where discharge rates exceeding one pound per second are required. The discharge rate is specified in NFPA 10.

They come in ABC, regular, or dry chemical rated for class B and C fires. Class B fires are defined as “flammable liquid gasoline, oil, grease, and all flammable gasses.” Class C fires are defined as “electrical fires or energized electrical equipment fires.”

High flow extinguishers are designed with a quick discharge rate enables the dry chemical agent to reach fires faster, providing increased firefighting capability as compared to a standard fire extinguisher. Applications include:

  • Propane filling and storage locations
  • Gas/fuel stations
  • Construction sites
  • Maintenance facilities
  • Hazardous material cabinets
  • Small paint booths
  • Marinas
  • Salvage/recycling centers
  • Warehouses/storage facilities

Hazards requiring a high flow extinguisher involve two main characteristics: presence of pressurized flammable gas and opportunity for a three-dimensional fire to occur. A three-dimension fire is a Class B that includes a liquid in motion (for example, pouring or dripping flammable liquids).

Fire Systems, Inc.

 If you have store flammable liquids on site, it’s imperative that you have the proper tools should a fire occur. A portable fire extinguisher is of course only one part of a larger fire protection system that includes an automatic sprinkler system, fire alarm system, etc. Don’t assume that every fire protection company understands your hazard type and how best to protect it. Choose a fire protection company with decades of experience in all aspects of fire protection, with a reputation for quality service. Fire Systems has been family owned and family operated for over three decades. Our reputation as a top fire protection company in the Southeast speaks for itself. We are a team of highly trained and highly experienced technicians, designers, managers, and more. Let us show you how seamless fire protection can be, no matter your hazard. Call us today at 770-333-7979 or visit our website for more information on all of the services that we offer.