Appendix B Oxidizing Agents by NFPA Classification

APPENDIX B

Oxidizing Agents by NFPA Classification

The degree of hazard of oxidizing agents may be evaluated by consideration of the National

Fire Protection Association (NFPA) classification for oxidizers. NFPA identifies four classes

of oxidizers with Class 1 nominally the least hazardous and Class 4 the most hazardous. The

four classes of oxidizers are as follows:

Class 1 oxidizer: An oxidizing material whose primary hazard is that it may increase the

burning rate of combustible material with which it comes in contact.

Class 2 oxidizer: An oxidizing material that will moderately increase the burning rate or

that may cause spontaneous ignition of combustible material with which it comes in

contact.

Class 3 oxidizer: An oxidizing material that will cause a severe increase in the burning

rate of combustible material with which it comes in contact or that will undergo vigorous

self-sustained decomposition when catalyzed or exposed to heat.

Class 4 oxidizer: An oxidizing material that can undergo an explosive reaction when

catalyzed or exposed to heat, shock, or friction.

Thus, the relative degree of hazard decreases in the following order for oxidizers:

4 > 3 > 2 > 1. The following table illustrates examples of oxidizers in each NFPA class.

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