HOW TO USE CALCULATOR
3.5. NFPA 704 standard
The National Fire Protection Association (NFPA) designed NFPA 704 as a standard system for the identification of the hazards of materials for emergency response. The standard provides a readily recognized, easily understood system for identifying specific hazards and their severity using spatial, visual, and numerical methods to describe in simple terms the relative hazards of a material. It addresses the health, flammability, instability, and related hazards that may be presented as short-term, acute exposures that are most likely to occur as a result of fire, spill, or similar emergency.
The NFPA 704 ratings are displayed in markings that are commonly referred to as the "NFPA hazard diamond." It identifies the hazards of a material and the degree of severity of the health, flammability, and instability hazards (Prior to 1996, the section "Instability" was titled "Reactivity"). Hazard severity is indicated by a numerical rating that ranges from zero (0) indicating a minimal hazard, to four (4) indicating a severe hazard.
| HAZARD | HEALTH | FLAMMABILITY | INSTABILITY |
|---|---|---|---|
| 4 | Very short exposure could cause death or serious residual injury even though prompt medical attention was given. | Will rapidly or completely vaporize at normal pressure and temperature, or is readily dispersed in air and will burn readily. | Readily capable of detonation or of explosive decomposition or reaction at normal temperatures and pressures. |
| 3 | Short exposure could cause serious temporary or residual injury even though prompt medical attention was given. | Liquids and solids that can be ignited under almost all ambient conditions. | Capable of detonation or explosive reaction, but requires a strong initiating source or must be heated under confinement before initiation, or reacts explosively with water. |
| 2 | Intense or continued exposure could cause temporary incapacitation or possible residual injury unless prompt medical attention is given. | Must be moderately heated or exposed to relatively high temperature before ignition can occur. | Normally unstable and readily undergo violent decomposition but do not detonate. Also: may react violently with water or may form potentially explosive mixtures with water. |
| 1 | Exposure could cause irritation but only minor residual injury even if no treatment is given. | Must be preheated before ignition can occur. | Normally stable, but can become unstable at elevated temperatures and pressures or may react with water with some release of energy, but not violently. |
| 0 | Exposure under fire conditions would offer no hazard beyond that of ordinary combustible materials. | Materials that will not burn. | Normally stable, even under fire exposure conditions, and are not reactive with water. |
The special hazards in use are -–W, which indicates unusual reactivity with water and is a caution about the use of water in either firefighting or spill control response, and OX, which indicates that the material is an oxidizer. Other self-explanatory symbols are occasionally used in an unofficial manner, but they are not compliant with NFPA 704 standard.
Citing this page:
Generalic, Eni. "SolCalc Help: NFPA 704 standard." EniG. Periodic Table of the Elements. KTF-Split, 27 Oct. 2022. Web. {Date of access}. <https://www.periodni.com/enig/solcalc_help/nfpa_704_standard.html>.
