Media

Vacuum Excavation - August 9, 2004

Vacuum excavation has gained acceptance in Australia, but is already widely used in the US. This involves using jets of air or water to loosen soil, which is then picked up through a vacuum hose . The primary application is potholing - the use of exploratory digging to locate services prior to major works.

Vacuum excavation is part of a conbined approach to safely identify and expose underground services, which starts with a call to Dial Before You Dig (DBYD) to obtain a map of the services, and can include electronic technologies such as ground probing radar.

DBYD provides a service to assist contractors to locate underground services prior to excavation, but there are still a number of contractors who do not avail themselves of this, despite a requirement under Workplace Health & Safety (WH&S) legislation to do so, and potential liabilities that could bankrupt a company, as insurance companies may not cover the liability for damage to services (this should be checked with the insurer). Under WH&S a company owner, site foreman and machine operator could all share duty of care responsibilities for a service interruption.

Brian Zeller, Queensland manager of DBYD, also highlighted the possibility of civil or even criminal negligence suits, citing a case in late 1999 where the final bill exceeded $120 million, with much of the liability falling on the operator of the machine. There is also the possibility of environmental damage and injury or loss of life in these incidents: each with their own additional liabilities.

Zeller advises contractors to follow the five "P's":

1) Plan - Such jobs are dangerous. Take time to plan the work in advance.

2) Prepare - Collect all utility plans, conduct site inspections and note hazards.

3) Pothole - Verify underground pipes and cables by potholing the area by hand, Electronic location services can also assist.

4) Protect - Brief all site personnel about the services likely to be encountered. Ensure that appropriate safety equipment is on site, and emergency numbers are known. Take all reasonable steps to secure the assess of other utilities near the proposed excavation.

5) Proceed - Proceed with caution AFTER all other steps have been taken. There can never be 100 per cent assurance that all underground assets have been located.

There is considerable scope for wider use of vacuum excavation.