NFPA 704: Understand the Fire Diamond

The NFPA 704 diamond communicates hazard information for emergency response. Its numbers are ratings within that system; they are not GHS category numbers.

Read each quadrant separately

The scale runs from 0 to 4

For the numbered quadrants, 0 is the lower end and 4 is the higher end of the hazard scale. Each quadrant has its own criteria. A rating is determined by applying those criteria to the material's properties; a generic number-to-adjective table is not enough to classify a product.

The white quadrant can carry OX for oxidizing properties, a barred W for unusual water reactivity, or SA for specified simple asphyxiant gases. Do not invent additional marks or assign a special-hazard symbol from the chemical name alone.

A reference example

The gasoline example in this library shows 1–3–0. It is an illustration, not a rating guaranteed for every gasoline formulation or installation. Use product-specific data and the applicable NFPA criteria.

Why an SDS category cannot fill the diamond

GHS hazard category 1 generally indicates the more severe end of a classification. NFPA 704 uses the opposite numerical direction. OSHA and NFPA explicitly explain that the hazard category numbers in SDS section 2 must not be used as NFPA ratings. Other SDS sections provide information that can support a separate NFPA assessment.

NFPA 704 focuses on emergency-response information. OSHA HazCom addresses workplace chemical hazards and includes chronic health hazards that the NFPA diamond does not describe. The systems therefore cannot be substituted for one another.

Check local placarding requirements

Whether a placard is required, where it belongs, which edition applies, and how an area containing multiple materials is rated depend on the adopted requirements and the responsible authority. This site does not calculate or approve placard ratings.

Already have the ratings? Draw the diamond with the NFPA 704 builder and download it as SVG or PNG.

Read the GHS label guide to understand the other layer of chemical hazard communication.