Fire hazard rating systems

The most well-known hazard rating system is by the National Fire Protection Association (NFPA) and is called the NFPA diamond. It is a multicolored diamond that covers three hazard classes as well as specidc other hazards, and is shown is Figure 3.1.2.3. This diamond is actually designed for dredghters and it represents the hazard under conditions of a fire—it is not specidcally designed for laboratory safety. (See Special Topic 3.1.2.2 How Is a Chemical Different in a Fire ) The diamond is subdivided into four smaller diamonds—each with its characteristic color. If each point of the large diamond is treated like a clock, you will And at 9 o clock a blue diamond for health hazards, at 12 o clock a red diamond for dammability, at 3 o clock a yellow diamond for instability, and at 6 o clock a... 

Like flammable gas compressors, the external lubrication system for large air compressors can present a fire hazard. Oil flow rates above 25 gpm (95 Ipm) and or oil capacity greater than 100 gal (379 I) may require fire protection. 

The hazard rating (NFPA) for sodium sulfite is 2, 0, and 0, for health, fire and reactivity, respectively. It is an eye, skin, mucous membrane, and respiratory tract irritant. Excessive exposure to sodium sulfite may affect the brain, respiratory system, and skin. Crystalline sodium sulfite is a stable compound. However, sodium sulfite solution will decompose upon reaction with air to form SO2 gas. It is a strong reducing agent and reacts with oxidants and decomposes on heating to produce SOj. 

National Fire Protection Association. System gives a qualitative rating for health, flammability, and spontaneity. These values range from 0 to 4, with 4 being the most hazardous. These can be used for an initial screen to sensitize engineers to the potential hazard. Quantitative values are published elsewhere for each separate issue health (TLV, STEL, IDLFl) flammability explosivity (upper and lower explosive limits). 

Fire testing used to develop automatic sprinkler system design criteria has shown that other factors are important to determine the overall fire hazard of containerized liquids. These factors include the liquid properties, such as liquid burning rate, fire point, specific gravity, water solubility, and viscosity, as well as the container design and size. These important factors have been incorporated into the sprinkler system design tables in Section 4-8 of the 1996 edition of NFPA 30. 

The NFPA 430 classification system, the fire hazard behavior of liquid and solid oxidizers that can increase the burning rate or cause spontaneous ignition of a combustible material. Also, the reactivity behavior of liquid and solid oxidizers includes those that can undergo a self-sustained decomposition or an explosive reaction. The definitions used to define liquid and solid oxidizer classes can be subject to interpretation. The NFPA 430 classification system is based on the Technical Committee s evaluation of available scientific and technical data, actual experience, and it s considered opinion. A listing of typical liquid and solid oxidizers by class can be found in the Appendix of NFPA 430. The oxidizers listed are assumed to be pure materials unless otherwise specified. 

---