What is the HSG47 Guidance for Underground Services?

By Wade Lewis

You’ve probably seen HSG47 referenced before or may have even been told you need to use it as guidance. But what is it? You’re not alone in wondering this. In fact, I get this question a lot when working with clients who are unsure what protection they need or if they are even affected by the HSG47 guidelines. 

As Director of Business Development (North) at Lion Safety, it is my job to walk clients through the legislation and industry jargon and guide them towards a better understanding of what products they need to protect their staff. I know how important it is to be able to break down the guidance and find where it applies to you.
In this article we will cover the following areas:

• What is HSG47?
• Who does HSG47 affect?
• How can I mitigate health and safety risks to employees?
• What are the dangers of non-compliance?
• What are the risks of underground services I need to worry about?
• What are my duties in HSG47?
• What protective clothing do I need to provide?
• How can I follow HSG47?

What is HSG47?

HSG47 is a set of guidelines that outlines the potential dangers of working near underground services. This guidance advises how to reduce risks to health and safety.

Who does HSG47 affect?

HSG47 is for all people involved in commissioning, planning, managing and carrying out work on or near underground services. It is also relevant to the owners and operators of the services.

You will need to apply the HSG47 guidance to your practices if you work in:

• Street works
• Road works
• Excavation, drilling and piling
• Demolition and site remediation
• Site investigation surveys
• Any other work that involves penetrating the ground at or below surface level

If you are unsure if this affects you, the guidance in the standard is to assume that, due to their widespread nature, underground services are present unless shown otherwise.

How can I mitigate health and safety risks to employees?

That is the million-pound question. Ensuring that you mitigate risks to your employees is tricky; how can you cover all bases? It does not have to be difficult. The following points are great places to start:

• Do your research on services in the area
• Conduct risk assessments
• Ensure adequate PPE is provided
• Consult with an established PPE or safety supplier who is technically knowledgeable 
• You may want to speak with your external health and safety advisory company (if you have one)
• Ensure you follow legislation and guidance like HSG47!
• Consult with your employees through
  1. Working groups
  2. Surveys 
  3. Staff training on the risks associated with their role and how they can mitigate them

What are the dangers of non-compliance?

When you are working with or around underground services, you run the risk of damaging them. Damage to underground services can cause severe injury or death. If you need any further reasons for caution, it could also cause disruption and environmental change, which will delay your project and incur considerable costs. 

Costs to you aren’t just from project delays; in the event of an accident you could be required to pay 6+ figure sums in compensation should a worker become injured or die on-site or from their injuries. 

Examples of this:

• BAS Castings Ltd was fined £60K + £1.3K in costs over burns requiring surgery and two weeks of hospitalisation.
• Amey was fined £600K + £15.5K in costs after a worker’s clothing caught fire. He sustained serious burns to his face, chest, arms, hands, legs and stomach. 

What are the risks of underground services I need to worry about?

There are 5 key risks here that you need to assess:

1. Electricity Cables
2. Gas Pipes
3. Water Pipes and Sewers
4. Other Pipelines
5. Telecommunication cables

Electricity cables

Why this is a risk to workers: 

Ever heard of an arc flash? These explosive events can kill a person instantly, or leave them with life-changing burns. When working with any kind of live electric cabling, there is a risk of arc flash when there is a chance that a cable could become damaged by a sharp object (like a tool) or crushed. This can also happen when cables have been damaged and left unreported and unrepaired, usually due to age deterioration.

Why this is an environmental risk:

Arc flash and the fire that can result from one can affect other services like gas pipes, which could lead to an even bigger explosion and more fire. 

Gas Pipes

Why this is a risk to workers:

A damaged gas pipe will leak. A gas leak has the potential for fire and explosion. This damage might happen while work is proceeding, or through age or poor maintenance. Gas leaks can suffocate you, with an even greater risk of suffocation from liquified petroleum gas (LPG), as it has a greater density than air and therefore struggles to disperse quickly. 

Why this is an environmental risk:

The risk of explosion and fire here is, as above, a risk to the environment and other services too. The other risk with gas leaks is that gases such as LPG also can travel long distances and accumulate at low levels, such as in basements and cellars.

Water Pipes and Sewers

Why this is a risk to workers:

The risk to pipes and sewers poses less of a risk of injury to people, however, the risk is still there. The risks listed in the standard are:

• Jets of significant pressure and intensity injure a person, which can also contain stones or hard objects from the ground and from around the pipe. 
• Leaks from underground pipes affect adjacent services and reduce support for other structures. 
• Damage to mains pipes resulting in flooding and leading to subsequent risks of drowning or rapid collapse of support to sides of an excavation. 

Why this is an environmental risk:

Water can and will enter gas pipes if the gas pipes are damaged.

Environmental contamination due to leaking sewage water carries its own set of risks. 

Other Pipelines

Why this is a risk to workers:

This depends on what type of fluid/gas the pipelines are conveying, but risks include:

• Fire and explosion
• Injury from the sudden release of the pipe’s contents
• Poisoning (if the pipe is carrying toxic liquid or gas)
• Asphyxiation (from inert gases like nitrogen and argon

Why this is an environmental risk:

The risks to the environment also depend on the contents of the pipe.

Often, a liquid will pose multiple risks; such as being both toxic and flammable. 

Telecommunication cables

Why this is a risk to workers:

The risk of personal injury to workers is stated in HSG47 as being ‘normally very low’. The reason for that is that there should be enough due diligence carried out before a project takes place to mitigate that. The telecommunications cable itself is not likely to cause an arc flash or a fire. However, this becomes a risk when other cables or pipes that were not known about get disturbed.

Why this is an environmental risk:

Damaged telecommunications cables can cause massive disruptions to the general public who rely on these systems, and they can require lengthy repairs.

What are my duties in HSG47?

Duties as a Client

You must:

• Make reasonable enquiries about underground services
• Pass any information you find out about this to both the designer and contractor.
• Supply only the most up-to-date information.
• Consider how contractors will or have addressed the risks from underground services

If you are unwilling to obtain this information, you must allow the contractor enough time to do so instead.

If you have had any previous work done, you may already have documents that contain relevant information that you can pass on to the other service teams involved.

Duties as a Designer

You must:

• Reduce or ‘design out’ the risks that may arise from damage to underground services. For this, you must know if there are underground services present so that you can reduce the risks where possible. 
• Provide information to those doing the work about the risks you’ve reduced as well as the ones that remain.
• Provide drawings detailing risks (if you feel this would better illustrate your point)

You may have to re-site the services as a way to avoid risk. If this is an option you want to take, you need to ask the service owners and operators to do this and provide adequate notice. 

If the work poses risk to electric cables, you may need to ensure these cables are not live before the work begins. You must contact the electricity companies as early as possible so that they can make arrangements. In some instances, this will not be possible, and you will need to find an alternative way of carrying out the work.

Duties as a Contractor

You must prepare safe systems of work for your employees by:

• Identifying hazards they are likely to encounter
• Assess the risks posed by these hazards
• Outlining what underground services are there and what tools, equipment and practices will be required to avoid damage to the services.
• Ensuring all workers have been fully briefed and have adequate training to work safely in the environment
• Provide information about the risks from underground services before your team arrives on site. 
• Provide information on underground services to the client and owners of other services you’ve encountered on completion of work. 

What protective clothing do I need to provide?

If your workers will be working or excavating near electricity cables, you must consider whether or not they need arc flash protection or flame-retardant clothing. 

PPE is always the last line of defence. Even when all the correct due diligence is carried out, there is always the chance that something may have changed that is not in the maps or plans you have. There are instances every year of people dying or becoming seriously injured because they hit a cable they did not know was there. 

When do my workers need Arc Flash protection?

Any time that a person is breaking ground, whether, for cables or pipe work, we would advise they wear arc flash protection. If you are simply resurfacing, it is highly unlikely that you will need arc flash protection, as the risk of a cable strike at that level is very low. However, if you are going to be working any further than the surface, there is a higher risk of a cable strike or discovery of a damaged line you did not anticipate being there. In these instances, it is safer to have additional protection for arc flash than not, even if you don’t anticipate needing it. 

When do my workers need flame-retardant clothing?

Flame retardant (FR) clothing versus arc protection clothing: what’s the difference? 

There are instances where flame retardant clothing is suitable, like when dealing with flammable liquids or chemicals, without the risk of high energy discharge or electrical discharge from either machinery or cabling. 

As soon as you are around the risks of electricity, FR clothing (often is also anti-static or AS) may not be enough. Some FR clothing might offer some level of arc protection, however, if it’s not tested to the arc standards, it should be treated as though it offers no arc protection. This is because FR clothing is manufactured to a standard that dictates it prevents flames from spreading across the surface of a garment, with anti-static properties reducing the build-up of static that is generated in a garment, thereby reducing the risk of a spark that could start a fire. An arc flash is an instant release of high energy with high-intensity heat, and it can vaporise anything that is not specifically created for arc flash protection (including your standard FRAS garments). The temperature of an arc flash is circa 19,000 degrees celsius, which is hotter than the surface of the sun. 

With that in mind, it is questionable whether your workers need FR clothing on its own when they are in an environment with the potential for an arc flash. You would have to be able to prove beyond reasonable doubt that the task they are carrying out does not merit arc flash protection. 

PPE for excavating

For a safe excavation, it is advisable to provide head-to-toe protection from arc flash due to the risk that an employee may come into contact with cabling (whether anticipated or not). 

Sample Kit List for full Arc Protection

With the understanding that it is advisable to provide arc-rated protection for any workers who may interact with underground cabling, the below is a full and comprehensive kit list for a worker in these circumstances who requires arc flash protection. To properly protect from an arc flash, all of the below items (aside from the footwear) would need to be arc-rated. Footwear does not necessarily need to be arc rated when breaking ground. Here, your risk assessment is very important, as that will dictate what other features you need your footwear to have even if you don’t need it to have arc-rated protection.

Head Protection

• Helmet (including full-face tinted visor and chin strap)
• Ear defenders
• Neck protector/neck tube/snood/balaclava

Upper Body Protection

Outer Garments

• Waterproof jacket with hood
• Softshell 

Mid-layers

• Sweatshirt/hooded sweatshirt

Under Garments

• Long sleeve t-shirt/polo shirt
• Bra (if required)

Lower Body Protection

Outer Garments

• Waterproof Salopettes/Trousers/Bib and brace

Midlayers

• Cargo trousers

Under Garments

• Long johns/base-layer leggings
• Boxer briefs
• General boot or compression socks

Hand Protection

• General handling gloves
• Full weather-proof leather gloves (if required)

Foot Protection

As per your risk assessment.

How can I follow HSG47?

Understanding HSG47 is the biggest hurdle. Once you understand the guidance, you will know more about the risks associated and will therefore be able to mitigate them better in your projects.

Your risks are posed when interacting with these services and especially when encountering them when plans have changed and the services moved, or if you were unaware that they were present at all. The services you risk disturbing are:

• Electricity Cables
• Gas Pipes
• Water Pipes and Sewers
• Other Pipelines
• Telecommunications Cables 

When following HSG47 guidance it is important to assess your role in mitigating risks as well as assessing the risks themselves.

Responsibilities are easily digested in three categories:

• Client – enquire about underground services to pass any information about them to the designer and contractor. 
• Designer – reduce and ‘design out’ risks where necessary. To do this you will need to have a good knowledge of the present underground services and may need to do your research. Supply any information about the services and risks found to the contractor. 
• Contractor – From the information you have gathered, identify hazards and make a detailed risk assessment. Brief and train all workers on safety practices specific to the underground services present before they arrive on site. Inform the client and owners of other services you encounter once you have completed the work.

Aside from fielding the risks, it is important to consider the correct safety PPE for your workers. PPE is the last line of defence, and therefore even more important to get right. The main question you need to consider when dealing with underground services is:

“Is there any chance my workers will come into contact with any cabling or equipment that could result in an arc flash?”

If the answer to that question is anything more than a certain, 100% ‘no’; consider arc flash protection. 

Now you’re familiar with HSG47, your next steps are:

• Do your research.

Make sure you gather as much up-to-date information about the underground services under, near and around where you will be working. This is your first step to mitigating risk.

• Make your risk assessment.

Once you’ve done your research, you can create a well-informed risk assessment and zero in on what you need to do to mitigate these risks through practice, tools, equipment and PPE.

• Start thinking about PPE.

If you have identified the PPE you need to provide for your staff; great! If you are still unsure; also great! In both cases, it is now time to speak to some reputable suppliers about your requirements. If you can show them your risk assessment, even better! 

If you want to speak to somebody about your PPE requirements, book a call with LION today.