NFPA Hazards

National Fire Protection Association (NFPA) hazard labels can be found in most laboratories, schools and hospitals throughout the country. Although these ubiquitous labels were mostly designed for emergency response and fire-fighting purposes in areas that present certain special hazard situations, their simple visual format makes them easy to interpret, and the information the labels include can be useful in an emergency. The NFPA label is a diamond separated in four color-coded, diamond-shaped quadrants. Each quadrant expresses the level of risk in a different hazard category.

Flammability

• The red diamond located at the top of the NFPA label describes the flammability hazard level in the area. Inside the diamond is a number between 0 and 4. The 0 describes materials that will not burn, such as water, and 4 indicates the presence of highly flammable materials, such as propane gas, that will burn and vaporize easily and quickly at normal temperature and pressure.

  As an example of how the NFPA labeling system is used, a firefighter approaching a site with a flammability rating of 0 would know that he can enter the building without a high risk of explosions. He would know to exercise more caution in a site with a flammability rating of 2, meaning that the site contains materials as flammable as diesel fuel.

Reactivity

• The yellow diamond on the right side contains information on the chemical reactivity, or instability, of materials in the area. It also contains a number between 0 and 4, in order of increasing severity. A rating of 0 indicates material that is stable even under conditions of high temperature and pressure, whereas a 4 indicates the presence of highly unstable materials, such as TNT, that are prone to explosive reactions or decompositions even under normal conditions.

Special Precautions or Protective Gear Required

• The white diamond at the bottom contains a space for symbols that indicate any special conditions or materials present on the site that may have an impact on the actions taken or equipment used by emergency responders.

  The NFPA officially recognizes only two symbols for this space. An "OX" indicates material with oxidizing properties, such as ammonium nitrate, an explosive fertilizer. A capital "W" with a bar running through it that warns responders not to use water when fighting a fire due to the presence of materials that react unusually with water. Nevertheless, depending on local fire codes, this space often also contains different, nonofficial symbols indicating the presence of acidic, alkaline, corrosive or radioactive materials. The NFPA believes these risks are already expressed in other areas of the labeling system.

Health

• Finally, the blue diamond on the left represents the health risk of materials in the area. Returning to the numbered scales, health hazards are measured from 0, which indicates the presence of materials that under the high temperatures and pressures of a fire exhibit no special material risks, to 4, describing materials, such as cyanide gas, that pose a deadly threat to human health if released. The value of the health diamond is of particular importance when emergency responders enter a hazardous site.