An important part of any construction site, safety signs are designed to communicate clear, concise messages. Failing to understand the message of a sign puts workers in danger of significant injury, which, in some cases, can be fatal.

Generally, safety signs should follow ISO 7010 which is an established system for the standardisation of safety symbols. This way everyone can understand the important safety message. Site signage can be customised to match a company’s branding but the text and symbols must be clear so that needless accidents are avoided.

Here, we take a look at the different types of signage that are both required and commonly seen on a construction site – a quick and useful training tool for workers and site visitors.

Warning Signs

Unlike others, this type of signage does not give instructions on what to do. Rather, it is intended to make individuals aware of a danger or hazard. They are found both inside and outside a construction site, with the text such as ‘Warning, Construction Site’ outside, or perhaps “Warning, Scaffolding incomplete” on site.

In terms of design, the symbols will follow ISO 7010 so there will be a black icon inside a black triangle on a yellow background.

When to use hazard and warning signs:

  • Electrical Hazards / High Voltage
  • Wet Floors and uneven surfaces
  • Asbestos
  • Scaffolding warnings
  • Working at height
  • Plant and heavy machinery

Mandatory Signs

Mandatory signs focus more on immediate action – they inform an individual of what they must do in order to keep safe, such as “Safety harness must be worn.” They are presented as a blue circle with white images and/or text in front.

When to use mandatory signs:

  • Enforcing PPE Requirements
  • Site Traffic Management
  • Visitor Information

Prohibition Signs

Prohibition signs are the reverse of mandatory signs – rather than instructing an individual on what they must do, these signs communicate to an individual what they must not do. This type of sign is often found at the entrance to a construction site, with text such as ‘No unauthorised access’, or “Keep off scaffolding”.

Prohibition signs are circular with a white background, red border, and red diagonal line across the center. Any text must be white and on a red panel below the sign.

When to use prohibition signs:

  • Entry Restrictions
  • No Smoking
  • Parking restrictions

Safe Condition Signs

Safe condition signs are those that alert people of a safe location in the case of an emergency. They can also be used to demonstrate where emergency equipment is kept when accidents occur.

This type of signage is a solid green square or oblong with a white symbol that is often accompanied by text.

When to use safe condition signs:

  • Fire Exit and emergency escape routes
  • First Aid station marking
  • First Aid equipment identification



Fire Equipment Signs

Although safe condition signs are used to locate emergency equipment in cases of accidents, a different type of sign is used to locate emergency fire equipment. This is because fires can spread very quickly, meaning the solution needs to be identified and implemented immediately.

Fire equipment signs are red in colour. To make them distinguishable from prohibition signs, they are square rather than circular. They also have white symbols and/or lettering.

When to use Fire Equipment signs:

  • Fire Alarm locations
  • Fire Extinguisher identification and use

Keep this site safe

As obvious as some of these may be, understanding site signage is essential in avoiding accidents. The construction industry is one of the UK’s most dangerous industries and every little helps in keeping sites safe. By being aware of the different types of signage, site workers will be able to react quickly to any potential hazard and improve on-site safety.

The signage can also help in minimising accidents with the public. Whether this is managing traffic outside a site or perhaps there are pedestrians who need guidance to take safe routes.

Site managers can further help improve the effectiveness of their safety signs by sourcing signage that is of high quality and is compliant with the latest safety standards – BS EN ISO 7010. At Stocksigns, we have been a leading UK supplier of UK safety signage since 1955 and have a wide range of products that are ideal for construction sites, so we are a good place to start!

Why not take a look at our full construction sign portfolio here.