Why safety signs matter on site
Safety signs give an instant, wordless instruction on a busy construction site, where workers may not all share a first language. Reading them correctly is a basic site skill, and the CSCS test checks that you can recognise each type on sight. The good news is that you do not have to memorise every pictogram: once you know the colour and shape rule, you can read a sign you have never seen before.
UK signs follow the Health and Safety (Safety Signs and Signals) Regulations 1996, and the symbols themselves follow the international standard BS EN ISO 7010. Together these set five categories, each with its own colour and shape. Here is what each one looks like and means.
The five categories at a glance
Start with the shape and colour. The shape tells you the kind of message, and the colour reinforces it: a round sign acts on behaviour, a triangle warns, and a square or rectangle gives information such as where to go.
Prohibition
Round
Warning
Triangular
Mandatory
Round
Safe condition
Square or rectangular
Fire-fighting equipment
Square or rectangular
Prohibition signs
Round · Red ring and red diagonal bar on a white background, black symbol
A prohibition sign is round, with a red ring and a red diagonal bar running over a black symbol on a white background. It tells you that an action is not allowed because it would create a risk. The red bar always sits over the symbol, so the message reads as a firm stop.
No smoking
No access for pedestrians
No naked flames
Warning signs
Triangular · Yellow background with a black border and a black symbol
A warning sign is a yellow triangle with a black border and a black symbol. It does not ban anything; it alerts you to a hazard nearby so you can take care and check what to do. The triangle shape is deliberately eye-catching.
General hazard
Risk of electric shock
Slippery surface
Mandatory signs
Round · Solid blue background with a white symbol
A mandatory sign is a solid blue circle with a white symbol. It tells you about an action you must take, most often wearing a specific piece of personal protective equipment. Treat it as an instruction you have to follow, not a suggestion.
Wear head protection
Wear eye protection
Wear ear protection
Wear foot protection
Safe condition signs
Square or rectangular · Solid green background with a white symbol
A safe condition sign is a green square or rectangle with a white symbol. It points the way to safety: escape routes, emergency exits, first-aid points and assembly areas. Green here means safe and where to go, not permission to start work.
Fire exit
First-aid point
Fire-fighting equipment signs
Square or rectangular · Solid red background with a white symbol
A fire-fighting equipment sign is a red square or rectangle with a white symbol. It marks where fire equipment is kept, such as extinguishers, alarm call points and hose reels. The red here is about fire equipment, so do not confuse it with a round red prohibition sign.
Fire extinguisher
Fire alarm call point
How to read any safety sign
If you cannot read the wording, the shape and colour still tell you what to do. A red round sign with a bar means do not. A blue round sign means you must. A yellow triangle means take care. A green square shows the way to safety, and a red square locates fire equipment. Learn that pattern and the test becomes far easier.
Three mistakes people make
- Treating green as a traffic light. Green marks safe conditions, first aid and escape routes. It never means carry on with the task.
- Reading blue as information. A blue circle is an instruction to do something, usually to wear PPE. Ignoring it is ignoring a requirement, not a suggestion.
- Expecting warning signs to be red. Warnings are yellow triangles. Red is prohibition or fire equipment. Mixing the two up means missing a hazard.
Safety signs quiz, five questions
Five safety signs questions in the real CITB format. Most turn on the colour and shape rather than the pictogram, so read those first. Pick an answer and it is marked straight away, with the reason it is right.
0 of 5 answered
Score: 0 / 5
Q1. What color is used for fire equipment signs?
Reveal explanation
Correct answer: A. Red
Fire equipment signs are red because red is associated with danger and urgency.
Q2. What shape are prohibition signs usually?
Reveal explanation
Correct answer: A. Circular with a line through it
Prohibition signs are circular with a red border and red line indicating an action is not allowed.
Q3. Which symbol would typically be found on a mandatory sign?
Reveal explanation
Correct answer: B. White pictogram
Mandatory signs contain a white pictogram on a blue background, instructing mandatory actions.
Q4. What symbol might you see on a mandatory sign?
Reveal explanation
Correct answer: C. A blue circle
A blue circle is used on mandatory signs to indicate specific actions that must be performed.
Q5. Which of these signs would you expect to find near a high noise area?
Reveal explanation
Correct answer: A. Wear ear protection
In high noise areas, a mandatory sign requiring ear protection will typically be displayed.
Answer all five to see how you did on safety signs
The real CITB test is 50 questions in 45 minutes, with a 45 out of 50 pass mark. Our free mock test uses the same format and needs no account.
Keep revising the rest of the syllabus
Safety signs are one topic of the CITB Health, Safety and Environment test. When you are confident here, use our free CSCS mock tests to cover the rest, then take a full 50-question mock test to check you are ready. Closely related topics include fire prevention and emergency procedures.