What is a flash fire?

Protection starts with understanding. Learn about flash fire and safety measures you can take.

The definition from NFPA standard 2112, “Flame-Resistant Garments for Protection of Industrial Personnel Against Flash Fire,” states:

A fire that spreads by means of a flame front rapidly through a diffuse fuel, such as dust, gas, or the vapors of an ignitable liquid, without the production of damaging pressure

Flash fires generate temperatures in the range from 1000ºF to 1900ºF.

Flash fire hazards

The main hazard of the rapidly moving flame front is ignition of flammable materials including clothing.

Preventing Flash Fire Injuries, Specification Standard and Test Methods

Similar to an arc flash, FR clothing is a precaution designed to give personnel some time to escape the situation.

The NFPA 2112 standard specifies:

  • The minimum performance requirements for flame-resistant fabrics and components (for fabric, thread, hardware, and labels)
  • Test methods for flame-resistant fabrics and components (six tests)
  • The design requirements for garments for use in areas at risk from flash fires (for hardware finishes, metal components, slide fastener tapes)
  • Certification requirements for garments for use in areas at risk from flash fires (certification program, inspection and testing, quality assurance program)

The major test in the certification program is the full-scale flash fire test (Instrumented Mannequin) according to ASTM F1930 Standard Test Method for Evaluation of Flame Resistant Clothing for Protection Against Fire Simulations Using an Instrumented Mannequin.

An instrumented mannequin is a unique and very complex test system representing a human body. It is equipped with a minimum of 100 thermal energy sensors uniformly distributed within each area in the mannequin. After the test garment is on, the mannequin is exposed to flames simulating a flash fire. The duration of flame exposure is three seconds. Data from the test is used to calculate burn percentage for second and third degree burns and distribution on the body.