Definition - What does NFPA 704 mean?
The National Fire Association (NFPA) hazard rating is a rating system for all chemicals and hazardous materials. The system uses a symbol on the container that has a combination of four colored diamond arrays within a bigger diamond shape. Numbers and alphabet codes are written on those diamonds, which combined denote the health risk, severity and vulnerability of the chemical or the hazardous material contained.
NFPA 704 is also known as the NFPA hazard rating, the NFPA diamond, and the fire diamond.
Safeopedia explains NFPA 704
In the NFPA 704 hazard rating system, the color codes denote associated risk factors. The colour blue denotes a health risk, red denotes flammability, yellow denotes reactivity and white denotes a special hazard notice. Depending on the gravity of the risks involved, numbers are written on the color quadrants on a scale of 0 to 4.
4 - May be fatal on short exposure
3 - Corrosive or toxic
2 - Harmful if inhaled or absorbed
1 - Causes irritation
0 - No unusual hazard
4 - Flammable gas or extremely flammable liquid
3 - Flammable liquid flash point below 100° F
2 - Combustible liquid flash point of 100°F to 200°F
1 - Combustible if heated
0 - Not combustible
4 - Explosive
3 - May explode if suitably initiated
2 - Unstable may react violently if mixed with water
1 - May react if heated or mixed with water but not violently
0 - Not reactive to water
Special Notice Key (White)
W - Water reactive
OX - Oxidizing Agent
SA - Asphyxiant gas