Decoding the Fire Diamond Sign


(Above) An NFPA 704 sign out in the wild. According to the  sign, whatever is behind that door is very, very dangerous and cannot be exposed  to water. (image: Flickr user johnwilliamsphd)

Cities are full of signs. Signs telling us where to go and how to get there;  signs suggesting things to buy and signs keeping us from where we shouldn’t be.  Every sign is a code of sorts, a graphic system linked to something else – an  idea, an instruction, a building. Typically, these codes are carefully designed  to be decipherable by as many people as possible – everyone, ideally. They  reduce meaning to its most essential components: RED=STOP. But occasionally in  cities, there are signs that aren’t intended to be read by everyone, coded  messages for specific agencies or civil service employees. These signs are  ubiquitous but largely indecipherable and mostly go unnoticed. One such sign is  NFPA 704 – perhaps better known as the “fire diamond.” [SOURCE]


(Above) A blank NFPA 704 panel (image: seton)

NFPA 704 is the American system for identifying hazardous  materials created by the National Fire Protection Association. It was first developed  in 1957 by the NFPA’s Sectional Committee on Classification, Labeling, and  Properties of Flammable Liquids “to safeguard the lives of those individuals who  may be concerned with fires occurring in an industrial plant or storage location  where the fire hazards of materials may not be readily apparent.” In 1961, the  NFPA formally adopted the primary-colored diamond design as a National standard,  providing emergency workers with a simple, readily recognized and decipherable  system of signage describing general hazards to help workers in planning a safe  and effective response.


(Above) Design regulations for the NFPA 704 standards (image:  NFPA)

These signs are found on chemical tanks, warehouse doors, and loading docks  all over the country – any industrial, commercial, or institutional building  that manufactures, processes, uses, or stores hazardous materials that “would  cause, or significantly contribute to an increased risk of serious injury,  incapacitating illness or increased risk of death.” They are exclusively used on  structures or containers; signage for vehicles carrying hazardous materials is  regulated by the Department of Transportation. Although the National Fire  Protection Agency standard describes the relative sizes of the diamonds and the  numbers, including the suggestion that diamonds used on building exteriors  measure no less than 15 inches by 15 inches, local authorities have final  jurisdiction over how the signs are implemented, including their location and  size.

The basic form is familiar to anyone who’s every had some sidewalk chalk and  a ball. A diamond divided into four smaller diamonds, each given a color code  and number to signify a specific hazard: the blue diamond is the health signal,  ranked according to the level of toxicity and effects of exposure to response  personnel; the red signifies the level of flammability, and the yellow indicates  reactivity. The white diamond is reserved for any other necessary information,  such as water reactivity, radioactivity, the need for protective equipment, or  specialized extinguishing agents. The number within each diamonds indicates the  severity of the threat, ranging from 0, indicating no hazard or unstable  materials, to 4, which indicates highly combustible, toxic, or reactive  materials that could cause death or major injury.


(Above) Symbols used for the white diamond (image: Safety  Sign)

With the exception of the poison and radiation symbols, NFPA 704 is almost  completely opaque to the average person and just fades into the background of  visual white noise produced by the modern American built environment. But to  those for whom they’re intended, the signs provide invaluable, and potentially   life-saving information. Other countries have their own unique standards,  such as the orange hazard symbols required on all European vehicles  carrying dangerous materials. Have you observed similar signs oversees? Are you  curious about other signs and symbols? Let me know in the comments!



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