Costly “excavation disasters” in NZ

April 18th 2005

Action needed to solve costly “excavation disasters” in NZ

An engineering specialist has called for an end to sloppy road works practices that are damaging underground cables and pipes in New Zealand.

Trevor Lord, of the Christchurch-based firm LORD Civil says his plan could take two years to achieve, but he believes if a start is not made now on achieving change, the cost of continuing under the present “hit and miss” system will escalate further from an already unacceptable level.

“Unfortunately, in many cases it is the ratepayer and the consumer who end up paying the cost of a lack of co-ordinated planning and co-operation between ‘utility’ companies and local and central government agencies that need to lay cables, pipes and other infrastructure,” he says.

The problem lies in contractors digging up streets and roads without being aware of exactly where existing pipes and cable have been laid. Trevor Lord says hardly a month goes by without media coverage of a serious “excavation mishap” somewhere in the country. Most often these mishaps will cut power or water supplies, and require expensive and time-consuming rectification work that inconveniences the public and the business sector.

“And those are just the incidents that make the pages of the newspaper or on radio bulletins,” he says. “It has reached a stage where there’s now minimal tolerance for this sort of mishap, but unfortunately there is not an effective system in place to stop the sort of collateral damage that is regularly occurring. A response that will stop these excavation disasters is called for – now.”

Mr Lord is lobbying for a solution in both New Zealand and Australia to what he says is an international problem. He says the problem New Zealand faces is complicated by the fact that underground infrastructure – power cables and water, gas, and drainage pipes – are made of differing materials, are buried in widely different ground conditions ranging from soil to concrete, and are laid at various depths. A “total package” of systems is needed to properly locate the underground infrastructure, including the traditional electromagnetic, radio-frequency based locators for metal pipes and cables, ground penetrating radar to find metallic and non-metallic pipes and cables, and vacuum excavation or potholing to “prove” that underground utilities are where they are supposed to be before full-scale digging begins.

Mr Lord says more than 65% of new cable and pipe infrastructure being buried these days is non-metallic. “Most often they are made of plastic. Unfortunately the types of ‘location technologies’ used in the past have assumed that underground pipe and cable infrastructure would mostly be metallic. In addition, the as-built records for these services – the ‘maps’ that show where pipes have been laid - have never been accurate enough.

“The amount of damage done has now reached a level where there is major collateral damage occurring regularly. This has implications for the integrity and long-term viability of underground systems, the health and safety of workers on site, and inconvenience and cost to the assets’ owners, contractors, and stakeholders alike,” he says. Also, contractors are now facing serious consequences of getting things wrong on the job – including Health and Safety penalties, risk of prosecution and financial problems arising from downtime, contract over-runs and loss of commercial reputation.

Trevor Lord is calling for a new level of “best practice” in managing the positional recording and re-location process for underground pipes and cables. He is following a plan that involves direct lobbying of local councils, industry groups on both sides of the Tasman and direct lobbying of key Industry asset owners who have been affected by accidental damage to underground infrastructure. Trevor Lord acknowledges it will not be easy making major change to established practices, but he says it can be done – to the benefit of the whole of New Zealand.

ENDS

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