ANSI Z535.2 suggests using a combination of upper and lower case text in a sans serf font. ANSI also recommends using upper case only lettering for short messages and to emphasis individual words. Here are a few other recommendations:
Use Direct Statements – The main objective of safety signs is to quickly communicate information that allows individuals to take the appropriate precautions necessary to avoid a potential workplace hazard. Using direct statements will reduce reaction times that will lead to fewer accidents.
Use Action Statements – Give instructions on how to avoid hazards. The statements used to convey these actions should be accurate, simple, direct and pertinent to the danger.
Define the Danger – Identify the specific hazard using clear and simple instructions in an easy to read font.
Consequence Statement – Specify and warn individuals of the potential consequences with a clear and accurate message.
Emergency Contact Information – Contact information should be easy available after the Action, Hazard description, and consequences statements.