Signs are used in a variety of ways and use different colours and shapes to mean different things. It is important to make sure you read signs and take advice from what they say. It is also important that signs are always clean and visible.
Red & White Signs denote "DO NOT" (Prohibition)
Blue & White Signs denote "DO" (Mandatory)
Yellow & Black Signs denote "WARNING!" (Warning)
One of the most important ones you are likely to use is one to tell people there may be wet and slippery floors because of a spillage, or a floor that has been washed.
Green & White Signs denote Information such as Fire and First Aid Information
You will also see specific Fire Signage which might combine a number of Colour Codes