NFPA 704 flammability quadrant

The top quadrant rating flammability.

Also known as: Red quadrant fire diamond, Fire hazard rating

Engineering & technicalSafety & hazardStandard profile

Meanings

The top quadrant of the NFPA diamond, carrying a figure from zero to four rating how readily the material burns.

Officially standardisedVerified fact
Rates how readily a material burns, from zero to four, on the NFPA diamond.
Contexts: Public information
Officially standardisedVerified fact
Is placed at the top of the diamond because it is the rating a responder needs first, so the placard's layout encodes an order of priority.
Contexts: Public information

The upper of four small diamonds, filled with a distinguishing colour and carrying a single digit.

IdentityHigh confidence: High confidence because the identity is defined by a current official standard, but only a single source has been found so far.
Historical originLow confidence: Low confidence because the historical origin is documented in encyclopedic references, but only a single source has been found so far, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is defined by a current official standard, but only a single source has been found so far.
Visual matchModerate confidence: Moderate confidence because the visual match is documented in encyclopedic references, but only a single source has been found so far.

NFPA 704, Standard System for the Identification of the Hazards of Materials
National Fire Protection Association · retrieved 2026-08-25
The standard defining the four-quadrant hazard diamond used on fixed installations in the United States. Cited for what each quadrant and rating means. Records are descriptive; they are not emergency response guidance and no record should be used to assess a hazard.

Last reviewed 2026-08-25

Meanings

The top quadrant of the NFPA diamond, carrying a figure from zero to four rating how readily the material burns.

Officially standardisedVerified fact

Rates how readily a material burns, from zero to four, on the NFPA diamond.

Officially standardisedVerified fact

Is placed at the top of the diamond because it is the rating a responder needs first, so the placard's layout encodes an order of priority.

Confidence

IdentityHigh confidence: High confidence because the identity is defined by a current official standard, but only a single source has been found so far.
Historical originLow confidence: Low confidence because the historical origin is documented in encyclopedic references, but only a single source has been found so far, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is defined by a current official standard, but only a single source has been found so far.
Visual matchModerate confidence: Moderate confidence because the visual match is documented in encyclopedic references, but only a single source has been found so far.

Sources

NFPA 704, Standard System for the Identification of the Hazards of Materials
National Fire Protection Association · retrieved 2026-08-25
The standard defining the four-quadrant hazard diamond used on fixed installations in the United States. Cited for what each quadrant and rating means. Records are descriptive; they are not emergency response guidance and no record should be used to assess a hazard.

Last reviewed 2026-08-25