COLOURS OF SAFETY SIGNS AND THEIR MEANINGS

When you’re on site, safety comes first. So, how do you make sure you and your team stay safe? 

The answer is safety signs.

They tell everyone what to do and where to go, helping to prevent accidents and injuries.

With so many shapes, colours, and categories, it can get confusing. 

We’ll keep it simple for you with this guide, so you know:

• How to choose site signage.
• Why safety sign shapes matter.
• When and where to use warning signs.
• What the colours of safety signs mean.

Read on for everything you need to know about safety sign colours.

WHAT THE LAW SAYS ABOUT SAFETY SIGNS

In the UK, site signage isn’t just a good idea - it’s the law.

The Health and Safety (Safety Signs and Signals) Regulations 1996 make it clear. If there’s a real risk to people on site, safety signs must be used, even when there are other safety measures in place.

In short, employers must:

• Use clear and easy-to-read signage
• Avoid creating confusion with excessive signage
• Ensure every sign tells people what they need to do or avoid

In short, clear and well-placed signs reduce the chances of accidents and injuries. Without them, you can face legal trouble, fines, or worse.

WHAT COLOUR SIGN IDENTIFIES A HAZARD?

When there’s danger, workers need to act fast.

Safety signs use colour, shape and symbols to deliver messages instantly.

Site signage is the visual shorthand every workplace needs to stay safe. Colours especially show you whether there’s a risk to avoid or a rule to follow.

Want to know what colours are mandatory for signs?

Here’s a breakdown:

WHAT DO RED SAFETY SIGNS MEAN? 

Red means stop, danger, or prohibition. It’s also the colour used for fire safety signs.

Red signs catch the eye and clearly warn of hazards.

They are usually circular with a red border and white background. A black icon often shows what is prohibited, and a red line through the symbol means ‘do not’. 

Fire equipment signs are usually rectangular or square with a red background and white symbols.

Examples include:

• No entry - Red circle with a white background and a horizontal bar through it
• No smoking - Red circle with a white background, cigarette symbol, and a red line
• Fire extinguisher - Red rectangle with a white extinguisher icon and optional flames

WHAT DO YELLOW SAFETY SIGNS MEAN?

Yellow means caution, or in other words, ‘watch out.’

Basically, yellow signs are warning signs. They alert people to potential hazards or health and safety risks in the area.

They’re always a yellow triangle with a black border and a black hazard symbol inside.

Examples include:

• Wet floor - Yellow triangle with a slipping person icon
• Warning: forklift - Yellow triangle with a black forklift icon
• Electrical hazard - Yellow triangle with a black lightning bolt

WHAT DO BLUE SAFETY SIGNS MEAN?

Blue safety signs tell everyone what to do to stay safe. Follow them. It’s not optional - they're mandatory.

They’re always circular, with a white symbol on a blue background.

Examples include:

• Wear eye protection - White goggles icon on a blue circle
• Hard hats must be worn - White hard hat icon on a blue circle
• Wash your hands - White hands icon under running water on a blue circle

WHAT DO GREEN SAFETY SIGNS MEAN?

Green signs point you towards safety. 

They guide people to emergency exits, first aid points, and assembly areas. Green signs are usually square or rectangular with white symbols on a green background.

Examples include:

• Emergency exit - Green rectangle with white running person and arrow icon
• First aid - Green rectangle with a white cross or first aid kit, and the words ‘first aid’
• Fire assembly point - Green square or rectangle with a white people gathering icon

ARE THERE ANY OTHER SAFETY SIGNS?

Not every sign fits into one category. Some combine elements to make the message clearer for high-risk areas.

You might notice:

• Signs with extra text - like a ‘no entry’ symbol with wording underneath
• Multi-message signs - they combine colours, shapes and symbols to warn of multiple risks

Find examples in our full range of multi-message signs.

WHY DOES THE SHAPE OF A SIGN MATTER?

With safety signs, it’s not just colour that counts - shape matters too.

Sign shape gives an instant visual cue about what it means, even before you read the text or symbol. 

For example:

• Triangular signs warn of hazards.
• Circular signs usually show mandatory actions or prohibitions.
• Rectangular or square signs give information about safe conditions or fire safety.

So, shape, symbol and colour work to catch your eye and get the message across - fast. 

This lets workers react quickly and efficiently, which is essential for busy, high-risk sites. 

UNDERSTANDING HEALTH AND SAFETY SYMBOLS

Warning signs are essential for every workplace. Even offices and shops need them.

Safety symbols guide your team to avoid risks and stay safe. They inform your staff about the danger, what to do, and how to reach safety quickly.

Here’s how to get it right:

1. Start with a risk assessment to identify all hazards on site.
2. Choose the right sign type for the risk. 
3. Order and install clear signage from a trusted supplier.
4. Train your team. Everyone should be aware of the signs and know what to do.

Ready to get started? Find the safety signs and workplace products that can keep your business safe.

Need something customised? We also offer custom site signage, depending on your brand.

Call or send us a message to chat with our friendly team.

HOW TO DISPLAY SAFETY SIGNS

It’s not just about what signs you use - it’s how you use them that matters.

A badly placed sign can lead to confusion, accidents and injury.

Your warning signs should be:

• Easy to see and read
• Positioned at eye level
• Placed in well-lit areas
• Glow-in-the-dark if visibility is low
• Not blocked by doors, equipment, or stock

TOP TIP: Keep your signs clean and clear. If a sign is faded, damaged, or covered, replace it immediately.

Other must-dos:

• Use trusted suppliers, like SMI
• Avoid putting up unnecessary signs
• Match the colour and shape to the message
• Educate new staff and all the colours, shapes and symbols

FAQs

WHAT ARE THE 5 MAIN SAFETY SIGNS? 

There are five main types of safety signs, each one classified by its colour:

• Prohibition (Red)
• Warning (Yellow)
• Mandatory (Blue)
• Fire Equipment (Red)
• Safe Condition (Green)

WHAT ARE THE 9 SAFETY SYMBOLS? 

There’s no set list of health and safety symbols. ISO 7010 includes hundreds of standard pictograms that can be used for all sign types.

WHAT DO THE FOUR COLOURS ON SAFETY SIGNS MEAN? 

The four main colours of safety signs are red, yellow, blue and green.

They mean:

• Yellow for warning or caution
• Green for safe routes or first aid
• Blue for mandatory action or rules
• Red for stop, danger, or fire safety

GET HELP WITH SITE SIGNAGE FROM SMI

Choosing site signage doesn’t need to be stressful.

At SMI, we’ve got a full range of UK-compliant safety signs and labels to keep your workplace safe.

We can also customise your signs to fit your brand and site requirements.

Need advice or want to learn more about our custom branding? Just ask.

Drop us a message, or give us a call on 0330 441 3500.