An underground utility survey is a crucial step in any construction or excavation project.
Utility
survey or underground services survey allows for the identification and mapping
of underground utilities. These utilities can include electrical cables,
drainage, water pipes, gas lines, telecommunications infrastructure, and
more.
By
accurately detecting and mapping utilities, potential conflicts and hazards can
be avoided, ensuring the smooth progress of your project.
At KB
Surveys we specialize in providing comprehensive underground utility survey utilizing
advanced technologies such as Ground Penetrating Radar (GPR) and
Electromagnetic Locator (EML). Our priority is to ensure accurate detection and
mapping of underground utilities for a wide range of projects, adhering to
industry standards like PAS 128.
Use of Electromagnetic Locator (EML) in PAS 128 utility survey
Another powerful technology we employ when performing utility
detection survey is EML (Electromagnetic Locator). It is one of the primary
tools used if conducing utilities survey. It operates by detecting and tracing
the electromagnetic signals emitted by underground utilities. Our surveyors use
advanced EML equipment to precisely locate buried utility lines, enabling us to
provide you with accurate information about their depth, alignment, and type.
Please note that not all utility surveys must meet level A of
PAS 128 industry standards (the most precise survey involving trial pits) if
you choose to keep the cost of utility survey down.
What is a utility survey?
A
utility survey is a crucial step in any construction or excavation project, as
it allows for the identification and mapping of underground utilities. These
utilities can include electrical cables, drainage, water pipes, gas lines,
telecommunications infrastructure, and more. By accurately detecting and
mapping these utilities, potential conflicts and hazards can be avoided,
ensuring the smooth progress of your project.
Having
utility survey completed in an early stage of the development might allow your
company to extend the boundary of the project. That is especially important
nowadays with the ongoing shortages of developable land.
Another
important aspect of utility survey is increased site safety. Utility strikes
during construction or excavation projects are serious risk. Damaging existing
underground infrastructure can have substantial financial repercussions on your
business, not to mention injuries to the workers and public or in the
worst-case scenario on site fatalities.
According
to UK DIRT Report, in 2023 there were 4 million holes and excavation dug across
United Kingdom every single day with 60,000 utility strikes which costed UK
economy £2.4 billion. The report observed that utility strike numbers over the
recent years show increasing tendency.
Utility
survey performed by trusted surveying company will greatly mitigate that risk
and should be considered in your utility damage prevention plan.
Using Ground Penetrating Radar (GPR) in PAS128 utility survey
Ground Penetrating Radar (GPR) is one of the primary tools used
if conducing utilities survey. By sending high-frequency electromagnetic waves
into the ground and analysing their reflections, GPR allows us to create
detailed subsurface images. This helps us identify not only the location of
utilities but also detect additional features such as voids, rebar, and
geological anomalies. By combining EML and GPR data, we deliver comprehensive
utility survey that leaves no room for uncertainty.
Utilities located with geophysical methods, such as Ground
Penetrating Radar (GPR) meet category B at PAS 128 accuracy levels. That means
you will know horizontal and vertical position (depth) of any detected object.
Ground Penetrating Radar (GPR) vs. Electromagnetic Locator
As already mentioned, Ground Penetrating Radar (GPR) and
Electromagnetic Location (EML) are totally different technologies:
GPR works by sending a signal into the ground and listening
for reflections from that signal and contains its own transmitter and receiver
within the unit.
EML works by detecting the electromagnetic signal that may
be emitted by power cables, or the energy from low frequency communications
signals which has ‘coupled’ onto metal services. Alternatively, in the case of
a metal service which is not a power cable, it can be induced to emit a signal
by accessing the service and clamping a separate transmitter onto it.
Let us explore the main differences between those two
techniques as when conducting a survey, they need to be approached in a logical
way and require training and experience to produce the best results.
Based on our experience and controlled experiments, Ground Penetrating Radar will recover the locations of more underground features compared to Electromagnetic Location methods (within the penetration and resolution limitations of a GPR) in a like for like test with no manhole access.
What is PAS 128?
PAS 128 refers to the Publicly Available Specification 128,
which is a widely recognized standard developed by the British Standards
Institution (BSI) for all utilities survey providers. PAS 128 provides
guidelines and recommendations for conducting utility surveys and determining
the accuracy level of utility information. It aims to improve the quality and
consistency of utility data collection and mapping processes.
Key features of PAS 128 specification
PAS128 defines four survey levels (D, C, B, and A), each
representing different levels of accuracy and data quality. These levels guide
utility survey practitioners in selecting the appropriate survey method based
on project requirements.
Level D: Desk-based utility records and historical information
are used for preliminary identification of utilities.
Level C: Site reconnaissance and visual inspection are conducted
to verify the existence of utilities.
Level B: Detection technologies, such as Ground Penetrating
Radar (GPR), are used to locate and map utilities.
Level A: Precise, high-accuracy methods, such as trial pits or
vacuum excavation, are employed to expose and verify the location and
attributes of utilities.
How is utility survey performed?
Our utility survey processes are strict and follow the steps below:
Desk-based research
The
first step in a utility survey is to conduct a desk-based study to gather
information about an area. This can include obtaining utility records and
plans, site history, photographs, and any previous survey data.
If
you cannot provide records information (STATS) we can obtain them ourselves.
STATS records offer us valuable insight into which utilities and services are
supposed to be present in the ground and roughly where they may be. The STATS
information is also very helpful for ruling out what is not expected within a
given area. Finally, having access to STATS records can help to identify
services which would otherwise be classified as unknown.
Site reconnaissance
We begin by understanding your project requirements and objectives. Our team assesses the site and reviews available plans and records to gather essential information about existing utilities.
How much does utility survey cost?
Utility
survey cost is estimated on the project-to-project basis.
When
requesting a quotation, it would be helpful if you could include a clear survey
boundary (something like a google maps image or a topographic survey, with a clear
line showing the extents of the area), in addition it would be helpful if you
can specify what kind of survey you would like (if you know).
If you
are unsure exactly what you need, contact us and we can discuss your
requirements in more detail.
For
more information about utility surveys, or to request a quote. Please contact
us at info@kbgprsurveys.co.uk or
fill in the contact form below.
Benefits of utility survey
Why choose us?
Our utility surveyors have extensive expertise and experience | |
Our utility surveyors were involved in major airport and highways infrastructure projects | |
We are trusted by large construction companies and local councils | |
We are honest and reliable in dealing with all our clients |