Safe excavation training

All Acorn Gardening staff must complete this training. Please read all the information and complete the questions at the end.

Estimated time: 5 to 10 minutes

As a landscaper your job sometimes involves excavation of areas which could house utilities such as gas, electricity, water and telecoms.

Damage to utilities can be extremely dangerous and costly. It is a legal requirement that all staff participating in excavation understand how to avoid damage to these services.

This short course is designed to teach you the basics of staying safe when carrying out excavation work. Practical training will follow this session.

These safety practices are to be used on all work. Responsibility lies with all members of the team, not just the manager or supervisor.

Definitions

Excavation: Anything which penetrates the ground or goes below surface level
Utilities: Cables, tubes, pipes and other things which are part of the electric, gas, water, sewerage or telecommunications systems.

What you need to know

The risks and dangers of damaging utilities
How to detect, identify and avoid utilities
Safe working practices

Section 1: Dangers

Damaging utilities can be extremely dangerous and is sometimes fatal. Despite the best detection practices it is never guaranteed that all utilities have been identified.

Electricity

Electricity is the most dangerous of all the utilities when damaged. Electrical injuries are usually severe and cause burns which are sometimes fatal.

Damage to electricity cables is usually caused by penetrating or crushing the cable but can also be caused by old cables which have deteriorated. Contact with a cable or arcing or the current can cause explosions and fires.

Gas

Damage to gas pipes can release flammable gasses which can catch fire and cause explosions.

Others

Other utilities such as telecoms, water and sewerage are not as dangerous but all are extremely expensive and can result in loss of essential services to customers, neighbours or more.

The cost

Damages to utilities are extremely expensive to repair. Where due diligence is not taken, you and your employer could be liable to pay the bill. This could result in financial difficulties.

Section 2: Detect – Mark – Avoid

To reduce the risk of damaging utilities we follow a process called DMA which stands for Detect Mark Avoid.

Detect is when we find the cables, pipes and other utilities under the ground. Marking them helps everyone to know where they are or could be. We make sure everyone Avoids them using the safe practices below.

Detect

When planning work which involves any excavation, a risk assessment and risk management plan should be created before any work can begin. This should include detection of any utilities. Below is a three stage process for detecting underground utilities.

1.Planning

Plans from various utility providers should be acquired prior to planning the works.

This responsibility is primarily on the customer who should be informed of their obligation and that failure provide plans could make them liable for any damages or injuries which come about as a result.

2.Site check and identification

Look for visible signs in the excavation area and surroundings which could indicate the existence of a utility. This includes:

Drains
Boxes
Scar marks
Telecoms boxes
Hatches
Street lights

It is likely that the utility will run in a straight line over the shortest distance between two points however this is not always the case. Do not dig based on this assumption.

3.Physical identification

When the likely paths of the utilities have been identified you have to confirm that you are correct physically. You can do this in two ways:

1. Use a cable detector. You must be properly trained to use this method/

2. Dig trial holes. This is where you use hand tools to uncover the utility at different points along its assumed route to make sure you are correct.

Mark

When utilities have been identified in or near the excavation area they should be marked to make sure everyone knows where they are. Utilities should be marked:

on the site plan
on the plans you received from the utility company
on the ground

Use an identifying marker such as red spray to indicate safe digging zones. Inside these zones the safe digging practices below must be used.

Unless a detector has been used, include a 500mm safety margin around the assumed path of the utility as shown in the image below.

Avoid

After the utilities have been detected and marked we need to make sure we avoid damaging them. Sometimes we will have to work near them or next to them. Here is the guidance we expect everyone to follow when working near utilities:

The site manager or supervisor is responsible for the initial briefing on locations and markings of utilities. Everyone should be physically shown where they are.
Everyone working near utilities needs to be familiar with safe digging practices.
When using an excavator (digger) near an area which is suspected to have a any utilities under it a spotter should assist the driver by observing the excavation for any signs of pipes, cables or tubes.

Only hand tools should be used when digging close to utilities.
Spades and shovels can be used but should not be thrown or spiked into the ground. They should be eased into the ground with gentle foot pressure.
Picks should only be used with care to remove lumps of stone etc. Do not use pics in soft clay near utilities.
Excavate alongside any cables rather than on top, final exposure of the cable should be with horizontal digging so that the force is controlled more accurately.

Take extra care when working in close proximity to utilities
When using hand held power tools to break up surfaces you should leave at least a 500mm (50cm) safety gap if a detector has not been used. Cables sometimes snake underground rather than sit in a straight line.

If a cable detector has been used this safety area may be reduced appropriately
To locate the utility under a hard surface like concrete without a detector you should carefully dig under the hard surface before removing it in sections.
Where it is not possible to leave a safety margin, other precautions should be taken to prevent damage before excavation is carried out.

Using cable location devices

Before work begins all cables should be located and marked
During excavation detectors should be used every 300mm depth to ensure accuracy.
People using the locator devices should have received proper training
Location becomes more accurate as cover is removed so locators should be used frequently during the process.

When risk of damage cannot be avoided

Where the risk of damage cannot be avoided the cable should be deadened by the owner/ provided for the appropriate amount of time.

What to do if you hit something?

Gas, if there is a gas leak or suspected gas leak:

Get away from the area, and tell everyone to evacuate
Evacuate nearby buildings and clear nearby areas in case of explosion
Call the emergency services

Electricity, if a cable is cut or damaged in any way:

If you are driving an excavator do not get out. You are more likely to get electrocuted outside the vehicle
Do not attempt to fix it
Get everyone to a safe distance
Call the local electrical damage line

Other utilities

Get to a safe distance
Mark off the area to prevent further damage
Inform the relevant authorities of the damage

Other important points

Don’t allow others to dig on our site without locating utilities or being briefed on where the no-dig zones are. If it’s our site and they hit something we may be liable.

This is only a general overview of the risks and how to manage them. If there is something out of the ordinary, ask your manager or request information from the office on how to proceed.

Test questions

You need to get then all correct to pass