The NFPA 704: Hazardous Materials Identification System standard protects the health and safety of individuals who respond to fire and chemical emergencies in facilities or storage locations where the hazards of materials are not readily apparent or known. The standard addresses the health, flammability, instability and related hazards that are presented by short-term, acute exposure to a material during a fire, spill or other emergency-related condition.
NFPA 704: Hazardous Materials Identification System is a simple, recognizable and easily understood marking system that provides a general idea of the severity of the hazards of a material. The standard applies to industrial, commercial and institutional facilities that manufacture, process, use or store hazardous materials. The NFPA 704: Hazardous Materials Identification System standard does not apply to transportation requirements, general public use or occupational exposure.
A system of categories, colors and numbers was created to provide basic hazard information. It enables firefighters and other emergency personnel to easily decide whether or not to evacuate an area or proceed with emergency control operations. The three principal categories of identification are health, flammability and instability. A numerical range of 0 to 4 indicates the severity of the hazard, where 4 indicates the most severe and 0 indicates a minimal hazard.
The information is presented in a color and spatial arrangement of the numerical ratings: health hazard, blue, at the 9 o'clock position; flammability rating, red, at the 12 o'clock position; and the instability rating, yellow, at the 3 o'clock position. (Figure 2) Alternately, the square-on-point field is permitted to be any contrasting color. If this is the case, then the numbers themselves must be colored coded. (Figures 1 and 3)
The fourth space at the 6 o'clock position is reserved for indicating unusual reactivity with water. It is designated by the letter W with a line through the center. No special color is associated with this symbol. If the space isnt needed to indicate reactivity with water, only then can the space be used to indicate other unusual hazards. For example, materials that possess oxidizing properties are identified by the letters OX. (Figures 2 and 3)