Safety signs

What are safety signs?

Safety signs are signs that mark a hazard, a ban, a required action or the way to safety, using colour, shape, a pictogram and sometimes a word. ISO 3864-1, the international standard for designing them, defines a prohibition sign, for example, as one that indicates “a specific behaviour is forbidden”. Great Britain’s 1996 safety signs regulations describe the four main kinds plainly:

ISO 7010 gives each registered sign a reference number whose letter is its category: W for warning signs, E for safe condition signs, F for fire equipment. W001 is the general warning sign. Fire equipment signs, such as the one for a fire extinguisher, are red squares in ISO 3864-1. American workplace signs are sorted by use instead: OSHA’s rule, 29 CFR 1910.145, has danger signs, caution signs and safety instruction signs.

Signal words on American signs

DANGER, in white on red, marks a hazardous situation that will result in death or serious injury if not avoided. WARNING, in black on orange, marks one that could. CAUTION, in black on yellow, marks one that could result in minor or moderate injury. NOTICE, in white italics on blue, is for practices not related to physical injury, and SAFETY INSTRUCTIONS panels are white on green. Those are the definitions in ANSI’s summary of its Z535 standard for product safety signs.

OSHA’s own sign rule has no warning sign. WARNING appears there only on tags, for a hazard level between caution and danger. A 2013 OSHA rule lets employers follow the ANSI Z535 standards instead, and quotes the view that the old formats “lack the ability to contain [the] symbols, more extensive word messages, multiple messages, and additional languages”.

Safety signs beside hazard symbols

The yellow triangles for biological risk, radioactive material, electricity and laser beams are warning signs in the 1996 regulations’ list, and they have pages of their own among the hazard warning signs: the biohazard symbol, the radiation symbol, the high voltage symbol and the laser warning symbol. The GHS pictograms are printed on a chemical’s label and on its safety data sheet, and are outlined in red with a black image. On American signs, a triangle with an exclamation mark beside the signal word is ANSI’s safety alert symbol, which sits in the signal word panel.

Lab safety symbols

Lab safety symbols are the signs on a laboratory door, and they come from several systems at once. Kansas State University’s lab signs carry the GHS pictograms for the chemicals in the room, the NFPA 704 fire diamond, and symbols for cryogens, loud noise, radioactive material and lasers. Under the diamond, each sign gives the location of the laboratory’s safety data sheets. The University of Houston’s door signs show the minimum personal protective equipment for entry, such as a lab coat or safety glasses, beside the hazards present.