Utility Surveys

UPC Classification

In 2010 Locaters devised, and delivered to our clients, a unique Utility Positioning Classification (UPC) system to communicate the certainty in field markings and utility plans. This simple language for conveying the precision of a utility’s position ensures designers, engineers and field personnel can be confident of the level of accuracy.

In 2013 the Australian Standard AS5488, Classification of Subsurface Utility Information (SUI), was published. Locaters’ UPC system is aligned to the SUI standard.

The Locaters UPC system uses four levels of classification to depict the varying certainty of utility positioning.

A = Validated Measured directly to utility
B = Traced Electronic detection of utility
C = Aligned To utility surface features (pit to pit)
D = Indicative As per utility plan or “best guess”

 

As the certainty of a utility’s position increases the risk of conflict decreases however it cannot be eliminated. Below are images we have developed for our clients to explain the UPC system and the levels of implied accuracy and corresponding risk.

explaining risk and certainty of utility locating mark up

 

Moving from D to A
With Class D indicating low-level certainty, this classification can be used to quickly capture all the utility information for an initial design. Selective spending on subsequent investigations will progress the quality of the utility information in targeted areas.

Retained Value
Unlike conventional plans, Locaters utility plans clearly communicate the UPC information allowing the recipient to understand exactly how successful the investigation was or, what limitations may have existed making them a more effective tool for future use.

Sample Survey
Below is a preliminary investigation using the Locaters’ UPC system. Areas of potential utility conflict would be brought to Class A before final design, construction or excavation.

sample utility survey

Class A - Validation

“Seeing is believing” – The positive identification of a utility is the highest class of the utility positioning classification, ‘Class A’.

Pit lids and exposed utilities rarely line up precisely with your point of excavation or construction. A cost effective approach to obtaining Class A utility information is using non-destructive/pipe safe vacuum excavation to expose a utility followed by survey to capture its X, Y, Z and other attribute data.

Locaters Pty Ltd are able to contract and coordinate vacuum excavation specialists on behalf of our clients. By outsourcing this additional service you will benefit from our un-biased ‘as needed’ management of their personnel and equipment within your project.

Level of Certainty
Subsurface utility information obtained through the positive identification of a utility is designated ‘Class A’.

A survey plan can have a mix of ‘Class A’,’ B’, ‘C’ and ‘D’ positions. Our clients benefit from a targeted approach where we consider “where we need to spend now and how can we prepare for the future?”

Once a ‘Class A’ classification is made its values are good for the life of that utility.

Class B - Locating

To determine the presence of subsurface utilities we use a variety of surface geophysical methods including electromagnetic detection, ground penetrating radar (GPR) and acoustic wave techniques. The depth, type of material and type of utilities influence the choice of locating equipment used.

Once we have located the subsurface utilities we provide corresponding field markings, in coloured paint for different services.

Level of Certainty
Subsurface utility information obtained through geophysical locating is ‘Class B’, meaning it has been traced electronically using an appropriate method of detection with any number of tools such as transmitters, sondes, trace reels and CCTV cameras.

The designated utility locations can then be surveyed and incorporated into plans to depict the alignment of the utility.

Class C - Detail Surveys

Locaters Pty Ltd have a number of qualified surveyors to provide full 3-dimensional topographical surface and subsurface feature surveys.

When it comes to utilities, we can improve on a ‘Class D’ position by simply aligning a known utility to a surface feature associated with that utility eg. stop valve or pit lid. This ‘Class C’ alignment can be made in the field, or overlayed on the detail survey CAD model produced by our team or supplied by you.

The advantage of having us produce the detail survey is both full surface and subsurface surveys can be undertaken in one visit.

Level of Certainty
When using survey to provide subsurface utility information the survey data reflects the level of certainty conveyed by the source ie. ‘Class B’ if it was located, ‘Class A’ if we could survey it directly and even ‘Class D’ if there is enough evidence.

When a utility is known to exist and has not been traced or exposed it can be incorporated into the report based on the alignment to a related feature. This is known as ‘Class C’ positioning.

Class D - Desktop Reviews

Utility management begins with analysing and consolidating utility records from Dial Before You Dig (DBYD), utility operators and other sources. At Locaters we know the right people to talk to, and we have good working relationships with asset owners, asset managers, designers and contractors engaged on major infrastructure and civil projects.

Level of Certainty
Subsurface utility information obtained through a simple desktop review has a low-level of certainty, (Class D); it is “best guess” information.

The desktop review quickly captures utility information for initial design. Desktop reviews indicate where utilities are supposed to have been built, not necessarily where they have been built. Locaters can then undertake further investigations to improve the quality of the information.

Utility Avoidance

Locating for ‘Utility Avoidance’ or ‘clearing’ is an important consideration for any surface penetration like geotechnical and environmental ground testing. Locaters’ multidisciplinary team can provide locating and surveying services in a single site visit offering an advantage over locate-only or survey-only companies.

Properly planned penetrations, well installation and follow-up survey reports can ultimately reduce your project costs which is vital when you are operating within tight margins.

Contact us to discuss your locating and surveying requirements.