Safety signs alert people to hazards. They may be as significant as a high-voltage electrical hazard warning or as minor as a wet-floor indicator. They are there to keep you safe, so you have to know how to interpret them.
OSHA Standard Signs
In the United States, the Occupational Safety and Health Administration (OSHA) has standards for workplace signs, and the American National Standards Institute (ANSI) sets standards for warnings on consumer and workplace products. The safety signs you see around you are most likely designed to OSHA standards.
OSHA standard danger signs use opaque red, black and white colours. Danger signs warn passersby of construction sites, hot or flammable equipment, electrical hazards and other situations that might cause serious injury or death.
The OSHA standard for caution signs is a yellow background, black panel and with yellow letters. But not all caution signs are OSHA standardised, and signs may have red or black lettering, though the background is usually yellow. Caution signs indicate areas where injuries can occur, such as areas that require helmets or hard hats, masks or earplugs. Some caution signs also indicate personal danger, like overhead clearances, moving vehicles and slippery surfaces.
The National Fire Protection Agency (NFPA) hazard identification system uses a diamond of four colours: blue for health, red for flammability, yellow for reactivity and instability, and white for other situations. A value of 0 on a colour means there is little to no danger of that hazard. A value of 4 means extreme danger is present. These signs are used mainly to help firefighters and other safety workers by indicating what hazards a container (such as a tanker truck carrying chemicals) or storage area may present.
Some signs related to safety signs are emergency signs. Emergency signs usually indicate fire exit doors and fire extinguishers. They may also indicate emergency phones and "break glass" instructions. Signs warning against touching, drinking, running and swimming alert you to the dangers of those particular activities in the area. In shark-infested areas, a "No Swimming" sign can save your life. In areas where flammable fumes are present, "No Smoking" is more of a safety issue than a lifestyle choice.