Jun 2, 200608:14 AMThe Life
Signs of Life: Fire diamond
Jun 2, 2006 - 08:14 AMWhen venturing into a Palm Springs industrial area (or any such neighborhood in most American cities), you'll notice white/blue/red/yellow "square-on-point" signs affixed to some buildings. The numbers on these signs identify the severity of health, flammability and instability hazards, ranging from 0 (minimal) to 4 (severe).
Letters on the bottom white diamond indicate special hazards, either
The left-side blue diamond indicates the degree of health hazard: 0 is minimal, 1 may lead to slight irritation, 2 could cause temporary incapacitation, 3 might result in serious residual injury, and 4 could kill ya.
The top red diamond rates flammability: 0 does not exhibit a flash point (the lowest temperature at which vapors passing from the substance into the air will catch fire spontaneously if a small flame is present), 1 has a flash point over 200ºF, 2 has a flash point between 100ºF and 200ºF, 3 has a flash point between 73ºF and 100ºF, and 4 has a flash point below 73ºF, which will singe your eyebrows pretty darn good.
The right-side yellow diamond shows reactivity: 0 is a stable material which does not even react with water, 1 may become unstable at high temperature or pressure, 2 is normally unstable but doesn't detonate, 3 might explode but requires a strong initiating force, and 4 eagerly enjoys going "KABOOM!"
References: NFPA and UWP.