Symbols for safety signage must be as simple as possible and contain essential information only.The symbols used must resemble the ones shown in Section 5-7 as closely as possible. Any minor deviations must not be capable of causing misunderstandings.Safety signs shall be made of materials suitable to the environment in which they are to be placed.Safety signs must be of a size and colour and have illuminating properties of a type whereby the signs are easily observed and understood.