16th April, 2025

Understanding Construction Site Safety Signs

Construction site safety signs are displayed to deliver a clear health and safety message. Failing to understand the meaning of a health and safety sign on site might mean you lose your life - or your job. In this post, we look at the different types of construction safety signs.

Understanding Construction Site Safety Signs header image

Health and safety signs are displayed everywhere on construction sites, from the site hoarding and entrance points to various locations throughout the site.

If you work on construction sites or have just walked past one, you are likely to have spotted some of these health and safety signs.

Construction site safety signs come in bright colours, like red, green, blue and yellow.

What are these signs there for, and what do they mean?

The 5 health and safety signs you will find on construction sites are the same types of signs you will find in other workplaces. But because construction sites are dangerous places, you will probably see more health and safety signs in this type of workplace, and because construction sites are often changing, with new activities and dangers happening all the time, it's even more important that you can understand and follow the signs displayed for your safety.

Construction site safety signs are not put up for decoration, and the colours haven't been chosen because they look pretty. Each sign has a meaning, and each colour represents a different message.

Knowing what construction health and safety signs mean is important because they could be warning you about a danger, or telling you to do something. And if you don't understand the sign, and fail to follow the message, you could get hurt, or worse.

Construction site safety signs are there for a reason. They deliver important bits of information to you, letting you know about the hazards to watch out for or requirements that you must obey.

All safety signs have to conform to the The Health and Safety (Safety Signs and Signals) Regulations.

Being familiar with the different types of signs means we will be able to spot:

So what do the different types of signs look like, and what do they mean? Let's take a look at some examples of each construction site safety sign.

asbestos do not disturb sign

Prohibition Signs

The first sign you might be familiar with is the prohibition sign, although you might just recognise it as a red danger sign. You will see this type of sign on the entrance to nearly every construction site, usually with the text 'No unauthorised access'.

Prohibition signs have a red circle with a crossbar on a white background. Any lettering is black.

prohibition safety sign

Examples:

Meaning:

Mandatory Signs

Mandatory signs are the opposite of prohibition signs. Instead of telling you not to do something, they tell you what you must do.

You can spot this type of sign throughout most construction sites, telling you what you need to do, for example, 'Safety helmets must be worn' or even 'Keep out'.

Mandatory signs have a solid blue circle with a white symbol and/or lettering.

mandatory safety sign

Examples:

Meaning:

danger excavations warning sign

Warning Signs

Warning signs don't tell you what to do, or what not to do, but they are used to make you aware of a danger or a hazard. They are literally warning you about something. The first sign you might see on a construction site is a warning sign, with the text 'Warning Construction Site' or 'Danger Construction Site'.

Warning signs have a solid yellow triangle (pointing up) with a black border. Any symbol or lettering is also black on yellow.

warning safety sign

Examples:

Meaning:

fire exit sign

Safe Condition Signs

Safe conditions signs can be considered the opposite of a warning sign. Instead of warning you about danger, they are alerting you to a safe place. You might see this type of sign on a construction site to let you know where the first aid kit is, where the fire exits are, or who to report to.

Safe condition signs have a solid green square or oblong, with a white symbol or symbol and text.

safe condition safety sign

Examples:

Meaning:

Fire Equipment Signs

Fire equipment signs let you know where fire equipment is. And like fire extinguishers, they are red. That might seem confusing because prohibition signs are also red. Fire equipment signs are square or rectangular so that you can tell them apart from prohibition signs.

You will find this type of sign on construction sites where the fire extinguishers are located, or at fire call points.

Fire equipment signs have a solid red rectangle with white symbols and/or lettering.

fire equipment safety sign

Examples:

Meaning:


Now you should be able to understand construction site safety signs, and importantly, make sure that when you see one, you can follow the health and safety message and comply with the instructions.

Help your team understand construction site safety signs by downloading our free toolbox talk for safety signs and check out the infographic below as a visual reminder.

safety signs meaning infographic
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This article was written by Emma at HASpod. Emma has over 10 years experience in health and safety and BSc (Hons) Construction Management. She is NEBOSH qualified and Tech IOSH.

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