You see these signs on any building that contains hazardous chemicals. The sign is called an NFPA panel. NFPA stands for National Fire Protection Association.

The idea behind these signs is to give firefighters some sort of advanced notice on what they are getting themselves into when they arrive at the scene of a fire. When there is a house fire, firefighters have a pretty good idea of what they are in for, but if there is a fire at a warehouse in an industrial park, it is very hard to know what chemicals might be stored there. The NFPA panel is a clear indication of what sort of dangers might lie inside.

The panel has four…