Trenching Controls: A Guide to Safe Trenching Practices

Why Proper Trenching Controls Are Critical for Site Safety

Not using the appropriate trenching controls can be fatal. WorkSafe is urging employers and workers to take trenching safety seriously.

Since 2017, four fatalities occurred in trenching incidents at Victorian construction worksites. To reduce the risk of incidents occurring during trenching work, employers and self-employed persons must be adequately prepared, have the right controls in place, and adhere to OHS rules and regulations.

Use our guide to safe trenching controls.

Before the trenching work begins

Employers and self-employed workers should create a documented safe system of work identifying the hazards and risks. They should:

• Notify WorkSafe at least three days before starting construction excavation work: https://www.worksafe.vic.gov. au/construction-excavation-notification
• Develop a safe work method statement (SWMS) prior to work commencing
• For all trenches where the depth exceeds 1.5 metres
• Where powered mobile plant is involved.

Preparation for trenching work is of utmost importance. Regardless of the depth of a trench, employers must:

• Have an emergency procedure is in place if there is a risk of a worker becoming engulfed
• Determine appropriate engulfment control measures
• Ensure the site can be secured

During the trenching work, engulfment control measures must be in place where workers are at risk of potential engulfment. Examples of such controls are:

• Benching or battering the walls to prevent collapse
• Shoring systems to support the sides
• Trench shields

Appropriate supervision by a competent person, experienced in trenching works should be provided focusing on factors such as:

• Workers remaining within engulfment control measures, including where protection is being progressively installed
• Materials, spoil and plant are kept away from the trench edge
• The trench and work area is secure and will prevent unauthorised access
• Any changes to the work or soil conditions.

Fall prevention tips

Falls into trenches can also lead to serious or fatal injuries. Not only do you need to protect workers entering and exiting trenches, but also anyone working nearby from falling into trenches. Fall protection controls may include, but are not limited to:

• Extending trench shield at least 900mm above the trench
• Fitting trench shield systems with an attachable guardrail system. Where possible, be fitted before installing the trench shields
• Appropriate fall protection in place during access/egress
• Exclusion zones of at least 2 meters where possible, around excavation works
• Securing the work area to prevent unauthorised access.

More information

Visit worksafe.vic.gov.au/trenching for further information on safe trenching works.

Download WorkSafe’s simplified guidance for trenching safety here.

Listen to more construction top tip videos from inspector Brian Chamberlin on reducing the risk of incidents while carrying out excavation works.