NFPA 704
Hazmat labeling system
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Related on Lably
Through Substance (chemistry), Hazard and Reactivity (chemistry)
Usage
NFPA 704 is designed to quickly inform first responders of the hazards of a facility during an emergency. Thus, they are placed in all places an emergency responder might enter a facility. The minimum requirements for placement listed by the NFPA are:
- Two exterior walls or enclosures containing a means of access to a building or facility,
- Each access to a room or area,
- Each principal means of access to an exterior storage area.
In many cases, storage containers and tanks are also labeled with fire diamonds.
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Codes
The four divisions of the square are typically color-coded, with red on top indicating flammability, blue on the left indicating level of health hazard, yellow on the right for chemical reactivity, and white containing codes for special hazards not covered by the first three squares. Each of health, flammability and reactivity is rated on a scale from 0 (no reasonable hazard) to 4 (severe hazard). The latest version of NFPA 704 sections 5, 6, 7 and 8 for the specifications of each classification are listed below. The numeric values in the first column are designated in the standard by "Degree of Hazard" using Arabic numerals (0, 1, 2, 3, 4), not to be confused with other classification systems, such as that in the NFPA 30 Flammable and Combustible Liquids Code, where flammable and combustible liquid categories are designated by "Class", using Roman numerals (I, II, III).
History
The development of NFPA 704 is credited to the Charlotte Fire Department after a fire at the Charlotte Chemical Company in 1959 led to severe injuries to many of the firefighters. Upon arrival, the fire crew found a fire burning inside a vat that firefighters assumed to be burning kerosene. The crew tried to suppress the fire, which resulted in the vat exploding due to metallic sodium being stored in the kerosene. Thirteen firefighters were injured, several of whom had critical injuries while one lost both ears and most of his face from the incident.
At the time, such vats were not labelled with the materials they contained, so firefighters did not have the necessary information to recognize that hazardous materials were present, which required a specific response. In this case, sodium was able to react with water to release hydrogen gas and large amounts of heat, which has the potential to explode.
The Charlotte Fire Department developed training to respond to fires involving hazardous materials, ensured that protective clothing was available to those responding, and expanded the fire prevention inspection program. Fire Marshal J. F. Morris developed the diamond shaped placard as a marking system to indicate when a building contained hazardous materials, with their levels of flammability, reactivity and health effects.