Safe Digging Practices And Avoiding Danger Near Underground Services

There's a saying "out of sight, out of mind". But failure to keep underground services in mind when carrying out construction work, particularly when that work involves digging, can be fatal.

You may not be able to see services that are hidden away under the ground - buried out of sight. That doesn't mean you can forget about them.

Because the ground is often where construction work starts, and those services might be in the way. Whether you are laying new pipes or cables, checking the ground conditions for a new structure, or excavating for foundations.

Underground services can be a hazard anytime you excavate or go into the ground, and should always be a consideration on your excavation risk assessment.

Contact with underground services can be deadly (and expensive).

Unintentional disturbance of live underground cables or pipes can cause:

• electrocution
• fires
• electrical ark
• gas release
• explosions
• contamination
• flooding

None of these things are good news - for your team or your project. And that's why you need to know about safe digging practices.

If you have read our guide on finding underground services, you will have a good idea of how to locate services on your sites. But what should you do if services are present? Controlling the risks involves keeping services protected, and your team safe.

The following precautions and safe digging practices can help you to avoid danger from underground services before and during excavation work.

1. Visual checks

Buried services are a major construction site hazard, particularly in excavation work. And you might be thinking you need fancy tools and equipment to locate them.

And we will get to that in number 3.

But it's amazing how much information you can gather from a simple visual check - no tools or equipment required!

Visit the site and visually check the site for obvious signs of services including patching of road surfaces, valve covers and manholes.

These visual clues are all indications of what lies beneath. They might not tell you all you need to know, but it's a good starting point for finding out what hidden services are on the site.

Find out more in underground services colours UK (and what they mean)

2. Check plans

Along with visual checks, there's another way you can find out about underground services without digging - and there's no safer digging practice than not digging at all!

You can get plans from utility providers and service operators to see what services are known to be present.

Plans from utility or service providers will help to establish if there are underground services within the work area, and give you an indication of the location of those services.

Service plans should be available on-site and used to help locate underground services. However, remember that service plans may not be 100% accurate.

3. Cable location devices

There is often uncertainty regarding the location of underground services, as they may have been in place for many years.

Even when markers, plans, and records show the location of underground services, there can be inaccuracies.

Plans give only an indication of the location and number of underground services on your site. Maybe services have been moved during repair works, or maybe the ground has moved. Perhaps some services were shown on different plans or missing, or the plans were incorrect in the first place.

Since plans are not always accurate in giving the exact position of services, cable and pipe locating devices should be used to develop plans that you know are accurate - and to mark services on site.

Cable locators can be used to trace services and get an accurate picture of where services are laid under the site. The locator eg. CAT scan is used to trace the line of any live pipe or cable and to confirm the location and depth.

4. Eliminate the hazard

Many health and safety hazards can be eliminated during the planning and design process, and the same is true when dealing with underground services.

Planning your project with underground services in mind can prevent or greatly reduce the risk of problems during the project.

It's not always possible, but if you can eliminate the hazard by preventing the need to work near underground services entirely, you can remove the risk.

When planning your project, see if the positioning of foundations and other structural elements can be designed to avoid any underground services already present. Or, check if existing services can be repositioned before works start.

5. Marking ground

Once identified ground marking should be used to mark up the services that have been identified on-site. This allows the workforce to easily located the position of services, and to take precautions when working nearby.

6. Make dead

Where you can't completely move services out of the way, you may need to make underground services dead for the work to proceed safely.

Contact the electricity company or service provider, as it may be possible to isolate the services during work to minimise the risk should accidental disturbance happen.

7. Assume live

Unless confirmed otherwise, always assume services are live.

If plans and other information cannot be found (or until you have fully located all of the underground services yourself), carry out work as though there are live buried services in the area.

It is better to assume a cable is live and play it safe than to assume it is dead and potentially put your life and the lives of others at risk.

8. Trial holes

We're at item 8 on our list and finally ready to do some digging! But not to get to work just yet, you still need to locate these sneaky hidden services.

You can't protect yourself from underground services or dig with confidence until you know exactly where they all are. You should have a pretty accurate picture from your visual checks, plans and scans, now you just need to confirm it.

A series of trial holes will confirm the exact position and depth of underground pipes and cables.

9. Safe digging

Whether tools or machines are used to excavate ground, cables and pipes can easily be cut with sharp tools or crushed with heavy machinery, causing serious damage to services below ground.

Any digging carried out close to services must be safe. Where there is a reason to believe there may be underground services present, hand digging with insulated tools should be used. Power tools or machinery should not be used within 0.5m of pipes or cables.

And safe digging practices are not just about the tools and equipment you use but also how you dig.

It is safer to excavate alongside services rather than on top of them. You can then dig horizontally with less force to expose services, reducing the risk of damage from downward pressure.

You may have a permit to work system, like a permit to dig, in place to control digging in high-risk areas such as near underground services.

10. Tool choice

Your choice of tool can reduce the risk to yourself and minimise the risk of damage to installed services.

• Spades and shovels are less likely to pierce cables than picks, forks or other sharp tools.
• Always use insulated tools and equipment when digging close to underground electrical services.

11. Support exposed services

Underground services are usually buried and supported by the ground around them.

Once exposed, underground services are no longer supported by the ground, so you may need to provide additional support.

Exposed underground services may also need extra protection if their location means they are at risk of damage. Never use exposed services as hand or footholds.

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Excavation work is a high-risk activity that needs to be planned, managed, and monitored on-site to be carried out safely. Download the excavation permit to work and control the excavation risks on your sites. Raise awareness of the risks with the underground services toolbox talk, and make sure your team know how to dig safely.