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Flammable and Combustible Liquid Storage and Handling

Mitigate fire and explosion risks at your facility

about flammable and combustible liquid hazards

Simply put, flammable and combustible liquids are liquids that can burn. The fire and explosion risks they pose, however, are anything but simple. Generally, flammable liquids are easy to ignite yet hard to extinguish. They can ignite at room temperature and do not require an outside heat source to ignite. Combustible liquids, on the other hand, are hard to ignite yet generally easy to extinguish. They usually require temperatures above normal working conditions, or an external heat source to combust.

Examples of flammable and combustible liquids include acetone, ammonia, butane, gasoline, and methanol (to name a few). These are found in common household items such as paints, thinners, waxes, and cleaners.

Despite the name, the liquids themselves are not what burn; rather, the vapors present above the liquids are burn and (possibly) combust. Flammable and combustible liquid vapors accumulate with the greatest concentration near the liquid’s surface and can ignite when exposed to heat. The lowest temperature where a liquid releases vapor and can ignite is known as a flash point. Flash points differ depending on the liquid, and whether they are considered flammable, or combustible. Once ignited, a flash fire will be produced, although combustion is not always a resulting factor. Due to these factors, a solid risk management program is integral to mitigating against these hazards.

flammable liquid losses

Critical to the understanding of the dangers of flammable and combustible liquids is the understanding that it is the resulting fires that pose the most risks. In the late 1980’s a paint warehouse experienced such an incident. The warehouse, containing over 1 million gallons of paint was destroyed due to a flammable liquid spill. The fire resulted in one injury, and over $30 million in damages. The fire department’s decision to not extinguish the fire prevented massive water contamination within the community, thus preventing a second disaster.

A similar incident occurred in 2007 at a chemical solvent distribution facility, where a fire occurred due to an incident involving ethyl acetate, a flammable solvent. The fire destroyed the facility, caused one injury, and cost the facility over one million dollars.

flammable liquid classifications

Classification of flammable and combustible liquids vary depending on the organization. The NFPA, Department of Transportation, and OSHA each classify the liquids using different formats.

The NFPA 30 classification is as follows:

  • Class IA Flammable Liquid: Flash Point <73 °F (22.8 °C), Boiling Point of < 100 °F (37.8 °C)
  • Class IB Flammable Liquid: Flash Point <73°F (22.8° C), Boiling Point of ≥ 100 °F (37.8 °C)
  • Class IC Flammable Liquid: Flash Point ≥ 73 °F (22.8 °)
  • Class II Combustible Liquid: Flash Point ≥ 100 °F (37.8 °C), and < 140 °F (60 °C)
  • Class IIIA Combustible Liquid: Flash Point ≥ 140 °F (60 °C) and < 200 °F (93 °C)
  • Class IIIB Combustible Liquid: Flash Point ≥ 200 °F (93 °C)

expertise in proper handling and storage

One of the first steps towards properly handling these liquids, and thus avoiding damage, is to carefully examine the liquids in your facilities, taking into consideration factors such as fire point, viscosity, specific gravity, and water miscible.

In addition to examining such properties, the storage of liquids and design of facilities are critical in mitigating fire risk.

  • When liquids are not in use, they should be stored in flame-resistant flammable storage cabinets, and should always be separated from other hazardous chemicals, and properly labelled
  • All metal storage drums should be grounded
  • When in use, flammable and combustible liquids should be housed within safety cans and used within a fume hood

The design and housekeeping of a facility are also critical factors. For example, sprinklers will not extinguish fires involving liquids of higher flashpoints. Ignition and heat sources should always be considered and separated from the liquids to prevent ignition. Open flames and hot work should also be limited when flammable and combustible liquids are present.

Facility design (including proper sprinklers, ventilation, detectors, and construction) should all be up to code, and properly maintained.

TÜV SÜD Global Risk Consultants (GRC) experts are on-hand to assist you in identifying your fire and explosion risk exposures. We assist you in implementing a proactive risk management plan in case of such events.

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