Are Your Trenches Safe?

Trenching and Excavation Safety 

During March, WorkSafe inspectors will be out on construction sites across Victoria where trenching and excavation work is underway. Site visits will focus on: 

• Notifying WorkSafe three days before construction excavation work involving a trench (if the excavation depth is more than 1.5 metres) 

• Underground and overhead assets 

• Collapse and engulfment controls 

• Ground conditions 

• Safe access and egress into trenches 

• Falls risks (live edges and installing trench shields) 

• Safe work method statements (SWMS) 

• Plant, including lifting equipment  

• Emergency procedures. 

In the last decade, 7 workers have died in trenching-related incidents on Victorian construction sites. The risks are real and deadly, which is why trenching safety is critical.  
 
To keep people safe during trenching work, employers and self-employed trades must:  

• Be properly prepared 

• Have the right controls in place 

• Follow OHS rules and regulations.  

Check out WorkSafe’s practical guide to trenching safety: 

Watch here.

Before you start any trenching work 

Make sure you: 

• Identify hazards and risks associated with construction excavation work 

• Choose the safest control measures, including preventing ground collapse 

• Complete a Worksafe excavation notification 3 days before work starts for trenches and shafts over 1.5 meters deep (where no building permit is issued) 

• Prepare a SWMS for all high-risk construction work (HRCW) before work starts 

• Develop an emergency procedure regardless of how shallow the excavation is. 

HRCW includes: 

• Trenches or shafts deeper than 1.5 metres 

• Where someone could fall more than 2 metres 

• Where a powered mobile plant is operating 

• Work in a confined space 

• On or near: 

• pressurised gas distribution mains or piping 

• energised electrical installations or services. 

Trenching risk controls 

To prevent ground collapse during trenching:   

• Bench or batter trench walls to prevent collapse 

• Use shoring systems to support the sides 

• Use trench shields  

• Keep materials, soil, and plant outside of the zone of influence or more than 500mm away from the trench edge. 

To prevent falls:  

• Extend trench shield at least 900mm above the trench 

• Fit trench shield systems with an attachable guardrail system before installing 

• Use fall prevention controls during access/egress 

• Keep exclusion zones of at least 2 metres around excavation works. 

Provide supervision to make sure:  

• Controls are in place before HRCW starts 

• Work follows the SWMS 

• Workers remain in engulfment control measures, including where protection is being progressively installed 

• The trench and work areas are secured from unauthorised access 

• Conditions are monitored continuously.  

Visit excavation and trenching on the WorkSafe website for more information on safe trenching practice.