Knowing what is under your feet

By Goldie Walker, the geophysics team leader at Geotechnics who has been involved in the inception of the National Utility Locating Contractors Association of New Zealand (Nulca NZ) and holds the position of its secretary alongside her day job

There are several moving parts to a civil or geotechnical project with many considerations to take into account.

Service locating is one such factor. However, it is unfortunately a consideration that is often dismissed. Nah, we don’t need a Service Locator – she’ll be right!

Most of the time, dismissals are fair and reasonable. A site  location may be greenfield with no known historical infrastructure or development, for example.

However, it is common  for project managers to gather all known service plans (a crucial step that should never be missed) and assume that all services are as shown.

And assuming can prove to be a glaring and costly oversight.

There may be services underground removed from plans. Some services haven’t even been drawn on plans at all; they are often removed from plans when they are deemed to be ‘abandoned’.

A number of utility owners keep abandoned services on their plans, but it is important to note that there is no way to tell if services have been kept or removed when the plans are digitised or re-drawn.

Occasionally (and most worryingly) a project manager may deem the services as ‘non-critical’, therefore taking the risk that if they damage them, it’s an easy and cheap fix. The assumption that service plans are accurate and that some services are ‘non-critical’ can cost a lot more than a service locator fee.

The term ‘cost’ goes beyond just the financial implications. There’s the repair technician time plus the cost to repair the damage; project cost by way of contractor down-time; potentially damaged equipment; potentially injured contractors (at worst, fatalities); lost time on the project; project deadlines pushed back (potentially impacting other projects); other flow-on costs for insurances; and damage to company reputation.

A real life case study

A client asked us to complete a geotechnical site investigation on a residential property and peg out locations for a drilling rig to complete Cone Penetration Testing (CPT).

The client provided us with service plans, clearly showing a low-pressure gas line at one end of the section with a stormwater and a sewer pipe running parallel along the length of the section.

The client said a representative from the gas company had marked the gas line and suggested we ‘eyeball’ any manhole lids to identify where the stormwater and sewer pipes go, before placing the CPT locations between those two pipes.

Service locating was proposed but quickly dismissed by the client as they considered the stormwater and sewer pipes ‘non-critical’, said they’d be easy to see any manholes, and said the locations can be moved – if the CPT strikes them.

After a lot of to-ing and fro-ing, we went ahead with the investigation and placed the CPT pegs.

We made it absolutely clear that we had placed the pegs as per the client-provided location plan and that we take no responsibility for any underground services, as we were not engaged to complete a Service Location.

The client was happy with this and the CPT team completed the drilling with no incidences.

We weren’t happy with the way things played out, however.

With this particular example, there was a lot more admin time spent than needed to be. Thankfully, this was the only additional cost.

Reducing incidences

Geotechnics has been working on producing a set of clear guidelines that enable our project managers to confidently assess the risks involved with underground services and to apply the appropriate measures where need be.

All known service plans must be gathered when planning a project. These must be understood, and we have Subject Matter Experts (SMEs) available to help with this. We have a table of distances from particular underground services where additional controls must be implemented, depending on the type of ground investigation being undertaken.

All these distances take into account the minimum approach distances provided by every utility owner (which is readily available on their websites or in the documentation received from beforeUdig). With this information at our fingertips, we can follow the Five Ps of Safe Excavation.

Plan: Request all service plans for your site (be aware that they are to be used as a guide only).

Prepare: Review the plans and engage a qualified locator to electronically locate the underground services/utilities.

Pothole: Asset owners may require you to pothole and identify their assets prior to excavation.

Protect: The exposed infrastructure by way of communication around the worksite with appropriate barriers

Proceed: Only once all previous P’s are satisfied and protective measures are in place

Within Geotechnics we have Nulca-affiliated Service Locators and an efficient hydro-excavation team that can help plan and prepare by providing assistance with understanding service plans, guidance in applying for the appropriate permits, on-site locating to a recognised standard (AS5488:1.2019), and safe hydro-excavation to expose particular assets as per asset-owner guidelines.

What is the industry doing?

Nulca NZ is a relatively new association in this country and it represents underground service Locators and those involved in locating and protecting New Zealand’s underground infrastructure.

Our mission is to build a utility locating industry that sets a global benchmark for capability, best practice, and innovation.

Nulca has been working closely with beforeUdig and fully support the roll-out of the Certified Locator Program. The professional training provided by Nulca equips locators with the highly technical skill and robust background knowledge necessary to work to the professional standard of AS5488:1.2019.

While Nulca works to a NZ-specific standard, we are putting together a set of best-practice guidelines. The aim is to have all locators producing the same high-quality work, communicating the appropriate information as needed, and educating anyone involved in projects where breaking ground is involved.

With communication and education, Geotechnics aims to have service locating as critical a consideration as engaging a drilling company to complete the work.

With the right communication and education, from project managers, site teams, locators, contractors, and anyone else involved with breaking ground, we shouldn’t run into too many of these projects as described above.

We need to squash that ‘She’ll be right’ attitude and remind people that we want everyone to go home safe at the end of the day.

If you want to get a project off the ground, you need to pay attention to what’s beneath it.



Related posts

Parting words from Jeremy Sole- a final column

Contrafed PUblishing

Smoko antics

Contrafed PUblishing

Nelmac’s water woman

Contrafed PUblishing