Safety Helmets must be Worn / Safety Footwear must be Worn / High Visibility jackets must be Worn Beyond This Point / Unauthorised Entry to this Site is Strictly Forbidden Combination Construction / Site Safety Sign is available in three different size. ThisCombination ConstructionSite Safety Sign can be self adhesive vinyl, rigid plastic or on foamex board, choices of 3mm, 5mm thickness. All the signs in this section conform to the Health & Safety Signs and Signals Regulations - BS 5499-1