NFPA 704 Diamond Information: Red Segment
Red region - Flammability
The red region of the RTK diamon indicates flammability and may contain either a 0, 1, 2, 3 or 4. These numbers indicate the level of flammability, explosion and ignition risk, and can be interpreted as follows:
- 4 Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily (e.g., propane). Flash point below 23°C (73°F).
- 3 Liquids and solids that can be ignited under almost all ambient temperature conditions (e.g., gasoline). Flash point below 38°C (100°F) but above 23°C (73°F).
- 2 Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur (e.g., diesel fuel). Flash point between 38°C (100°F) and 93°C (200°F).
- 1 Must be pre-heated before ignition can occur (e.g., canola oil). Flash point over 93°C (200°F).
- 0 Will not burn (e.g., water).