White Card Update: Managing Excavation Risks


Elliott Brown

One of the most dangerous construction activities that can occur on a building site is Excavation. Each year workers are injured and some killed because of incidents resulting from excavation work. Most these incidents are a result of the side walls of the excavation collapsing or machinery tipping over into the trench or people being struck by the excavator bucket.

When engaging in any construction activity as dangerous as excavation, work must be properly planned, managed, supervised and executed.

Workers involved in excavation work as well as those working in the vicinity must be aware of the hazards that this type of work presents and should also be trained about the procedures that are implemented to control the risks associated with excavation work

Because excavation activities can involve significant hazards a high degree ofmanagement commitment is required which should involve a hazard identification, risk assessment and development of a safe system of work.

Workers involved in excavation work should be protected using shoring support for the excavation, battering sloping the excavation or other suitable methods.

A risk assessment must be carried out depending on the activities that will be undertaken and a safe system of work should be prepared and implemented toprotect workers.

  • Some of the most common hazards related to excavation work are:
    contact with underground services
  • contact with overhead lines
  • collapse of the excavation’s sides
  • materials falling onto people working in the excavation
  • people and vehicles falling into the excavation
  • people being struck by plant
  • undermining of nearby structures
  • ground water
  • soil
  • access to the excavation
  • fumes
  • accidents involving members of the public.

Remember the following basic tips when working with trenches:

  • Ensure that adequate personal protective equipment be utilised correctly. Workers should have received training on the relevant PPE because if not used correctly, their effectiveness is reduced. The risk assessment stage of construction safety should determine which PPE are to be utilised depending on the hazard present.
  • Ensure the appropriate signage to warn workers not involved with trench work of the hazard and others visiting the site of the hazard.
  • Avoid solitary work because of the possibility of collapse. It is simply not safe to work alone in a trench or excavation. If the trench should collapse or an accident should happen you may only be found much later when it is too late to get help or medical assistance.
  • Erect the proper barricades to keep workers separated from the hazard as much as possible.
  • Never try to gain entry into a confined space unless you are trained to do so because these spaces present a unique hazard that can be deadly if you are not sufficiently trained.
  • Tunnels, shafts and trenches should have entry and exit openings that are large enough for a properly equipped person to pass through without danger of it collapsing. The size and number of openings also have an impact on the ventilation which needs to be kept in mind.