I wrote an article for the 2019 special edition of the Damage Prevention Professional Magazine entitled ROI on Making Underground Facilities Locatable in which I discuss the economic cost of not making underground assets traceable.
The article focused on the impact of poor traceability of non-conductive buried assets like plastic gas pipes and fibre optic cables or ducts.
At a rough guess, difficult service locates are costing the New Zealand economy hundreds of thousands of dollars annually. While that sounds like a bold statement, I'm confident that if we added up the unnecessary time and resources required to locate poorly recorded and installed underground assets, we would be astounded at the economic impact.
As a professional Locator, I see the consequences of poor traceability every day, and I know first-hand the unnecessary cost involved.
A classic example of a ULS client made me so angry I felt compelled to comment.
Engaged to do a seemingly straightforward residential underground gas line locate, I spent a ludicrous amount of time trying to find and mark it. The job sounded simple enough, and many clients would rightly expect that in engaging a certified Locator, it wouldn't be a big deal.
In the end, the outcome was a successful locate for my client, but not without considerable effort and leaving my client's lawn looking like they had a severe rabbit problem.
Unfortunately, the client paid for the additional time on something that should have been a simple task.
Why did it take so long?
Modern distribution gas lines are made of non-conductive polyethylene (PE) and can't be "energised" with electrical current for tracing. To make PE gas lines traceable, they are buried with a tracer wire. Tracer wire is a small conductive wire that helps in locating and tracing the gas line.
It's annoying to arrive for a gas pipe locate to find no tracer wire or worse, a wire that is broken or has been improperly installed, and doesn't work.
When laid by the gas company contractor's, this gas line had no tracer wire.
A professional Utility Locator has other options like Ground Penetrating Radar (GPR) to help locate non-conductive services. If you're not familiar with GPR, think "fish finder" for underground pipes and cables. This method is less effective than tracer wire and more time-consuming.
In this particular case, even GPR didn't immediately provide the outcome I was after.
The gas company asset plan showed two pipes crossing the property boundary from the road, one a steel pipe, indicated as disused, and the other a live 10 mm plastic (PE) gas line.
The metal pipe was easy to find with GPR. Done in just a few minutes, but that was only half the answer needed. The asset plan showed a second pipe 0.2 m away from the disused line. Despite careful scanning with GPR, it wasn't evident.
A Locator's last resort is to carefully hand dig to find a service. Not always easy and often very time-consuming.
In this particular situation, at the property boundary, there was no evidence of the second pipe despite plenty of digging. At the gas riser next to the house, two gas lines were present.
With two gas lines shown on the asset plan, there was the possibility the live gas line took a different path to the street, but there was no evidence of this. I even considered the live gas pipe might be underneath the disused pipe, which it turned out to be at least in one small section.
Finally, after careful hand excavation every meter starting at the house, all was revealed. Halfway across the lawn, the installers had run the new plastic (PE) gas line through the older disused gas pipe to the front boundary.
At the gas meter there were two pipes, but at the boundary, only one. Mystery solved!
So how could all this extra effort and cost have been avoided? Pretty simple really.
If the contractor had installed tracer wire, as they were required to do, locating the new gas line would have been a simple job, done in a few minutes. Even in doing such a poor job of the installation, had they at least documented the as-laid plan correctly the situation at the boundary would have been instantly clear.
Inevitably the cost burden of poor workmanship is transferred to someone else, namely my client.
It could just as easily have been the local city council with ratepayers picking up the tab, a local utility with costs coming out of operational budget, or a state entity with the taxpayer footing the bill.
The cost difference between an easy and challenging locate is not insignificant. Incurring the same unnecessary costs every time a buried service is traced, over the full lifetime of the asset could be in the thousands of dollars.
In my ROI article, I introduced the concept of a Lifetime Service Locate Cost (LSLC for short) which is a way to quantify the costs of easy versus difficult locates and highlight the return on investing in simple traceability techniques like tracer wire.
Economic costs aside, easier tracing reduces the risk of accidental service damage.
In the case I outlined above, a contractor who took the gas company plans at face value and decided to remove the old pipe would have cut a live gas line, with potentially serious consequences.
In my opinion,
- Higher standards of asset installation,
- less focus on short-term cost-saving,
- mandatory traceability elements with non-conductive utilities,
- proper consideration for future health and safety risks, and
- quality assurance in sub-contracted underground asset installation civil works,
would go a long way toward eliminating the situation I've outlined above.
All these practices would potentially save the New Zealand economy millions of dollars over the coming decades.
Innes Fisher is the founder and Managing Director of Utility Location Services New Zealand. He is a professional certified Locator active in the field and the New Zealand damage prevention community. Past President of Nulca New Zealand, international speaker and author.