Damage to underground utilities from excavation and trenching activities is more common than is generally believed. Many construction projects require some degree of excavation or trenching and it is critical that all efforts are made to prevent damage to these utilities.
Underground utilities can include, but are not limited to the following: communication lines, power lines, natural gas pipes, sewers and water pipes, and alarm systems. Each type of underground utility presents its own hazards and protection problem. There is a significant injury exposure to workers from explosion, fire, asphyxiation, and electrocution. Equipment can also be damaged and business interruption can occur.
There should be a written procedure for conducting utility locates. The procedure should include written documentation that the utility locate has been completed. Simply receiving verbal confirmation is not sufficient. Documentation confirming all necessary precautions have been taken is very important in the event a utility is damaged. Whenever excavation or trenching is performed, or heavy equipment is moved, the necessary precautions must be taken to identify utilities and minimize the potential for damage.
Here are items to consider adding to your checklist to address activities before and during any excavation or underground construction project.
Before you dig
1. Utility locate requests
Each province has a designated hotline that deals with underground service locate requests. For example, in Ontario there is a toll-free number called On1Call. In your request, be sure to provide information about who will be conducting the dig, when and where it will be occurring, the maximum depth that will be reached, the type of work, and your method. You will need to wait until your area has been cleared for digging. A locate request helps prevent damage to buried utilities and lowers the risk of unforeseen costs.
When you receive a response to your request, you will be notified of locations of all underground services. This may include utilities related to gas, water, electrical, cable TV, telephone, and pipelines. You may also be provided with a diagram of locate information which you should keep a record of.
Before beginning the dig, determine the potential hazards of any utilities you may be in contact with and methods of controlling them. Make a list of utility services that must be contacted before you start work.
It is important to keep reports of your entire excavation. If possible, use a standardized form to collect data, such as an underground utility checklist. You should also keep documentation of locate reports, and clearance and utility supporting methods. In the event of an emergency or any damage, have a plan ready to respond as quickly as possible.
If you identify a utility that was inaccurately marked or not previously known of, indicate this in your reporting. You should also keep a record of contact information for all facility owners. For more information on best practices regarding documentation, refer to the CCGA’s damage prevention guide.
1. Be aware of markings
All buried utilities are marked using paint, stakes, or flags that follow the Universal Colour Code for Underground Utility Lines:
White: Proposed excavation
Pink: Temporary survey markings
Red: Electric power lines, cables, conduit, and lighting cables
Yellow: Gas, oil, petroleum, or gaseous materials
Orange: Communication, alarm or signal lines, cables, or conduit
Blue: Potable water
Purple: Reclaimed water, irrigation, and slurry lines
Green: Sewers and drain lines
If there are no markings visible, report this to your provincial underground utility authority as well as facility owners. The work zone will need to be re-marked using the codes above.
2. Damage prevention
A minimum of two workers should be present during the dig including the machine operator. There should be a buffer zone on each side of a utility marking – for example, during a soft excavation (hand-digging), there needs to be a one-meter buffer zone.
Avoid using sharp tools, which can puncture and damage underground services. Instead, use hydrovac equipment. A hydrovac truck, for example, has a high-pressure water and vacuum system. This helps wash away dirt to safely expose piping and other utilities such as underground irrigation systems, the insured’s gas lines, and landscape electrical wiring. In some cases, these are not identified in preliminary locate diagrams because they are not part of a building’s main incoming services.
If you come across any line breaks or damage, immediately stop excavation work, call 911 or emergency services, and close the site. For more information, refer to Info-Excavation’s safety checklist.
Take care of your business, your workers, and your bottom line
Using a good underground utility checklist and other standardized documents for all excavation work can help protect you from many safety risks. As an added safety net, consider investing in construction insurance to address builder’s risk and wrap up liability. For more information, browse our construction & contractors insurance page today!
This blog is provided for information only and is not a substitute for professional advice. We make no representations or warranties regarding the accuracy or completeness of the information and will not be responsible for any loss arising out of reliance on the information. Terms, conditions and exclusions apply to coverage. See policy for details.