The Essential Guide to Utility Survey Mapping
At Technics, we have been at the forefront of delivering precise and reliable underground utility surveys across the UK for over 25 years. Our commitment and expertise in underground utility mapping ensure clients across various sectors receive accurate, detailed, and reliable results tailored to their project needs.
What is Underground Utility Mapping?
Underground utility mapping is an essential process in modern construction and infrastructure development, involving the accurate detection and mapping of the subsurface environment, such as:
- Gas pipelines
- Water mains
- Electrical cables
- Telecommunications lines
- Sewer systems.
Utilising technologies like Ground Penetrating Radar (GPR) and Electromagnetic Location (EML) systems can provide a clear and comprehensive view of the assets beneath the surface. This information is crucial for planning, design, and excavation activities, ensuring safety and efficiency throughout the entire project lifecycle.
Our Vacuum Excavation service further enhances our capabilities by safely exposing utilities to fulfil the PAS 128:2022 specification quality level Quality Level A (QL-A).
The Importance of PAS 123:2022 Compliance
The PAS 128:2022 specification, developed by the British Standards Institution (BSI), provides comprehensive guidelines for underground utility detection, verification, and location of underground utilities. It includes updates on training and qualifications for practitioners, post-processing in detecting surveys, and controls for the accuracy of detection methods. This standard sets a benchmark for all practitioners, ensuring high-quality and reliable survey data for clients.
PAS 128:2022 outlines four survey types:
- Type D: Desktop utility records search
- Type C: Site reconnaissance
- Type B: Detection using geophysical techniques
- Type A: Verification through exposure (e.g., vacuum excavation)
Each type corresponds to a different quality level, with Type A (QL-A) providing the highest level of accuracy.
What Does Underground Utility Mapping Entail?
Underground utility mapping involves the detection, verification, and accurate recording of buried services using a combination of desktop research, advanced geophysical survey techniques, and on-site verification methods. The aim of this process is to provide a full and comprehensive picture of the subsurface environment before any ground is broken.
A full utility mapping survey typically includes the following:
- Gathering existing records and statutory utility plans from providers.
- On-site reconnaissance or visual inspection to assess and confirm surface features.
- Non-invasive geophysical detection, such as electromagnetic and radar-based methods.
- Direct utility verification through safe exposure techniques like vacuum excavation.
- Delivering data in CAD or GIS formats for integration into planning and design processes.
This approach helps project teams avoid costly surprises, manage risk, and plan with greater certainty.
How Is Underground Utility Mapping Carried Out?
At Technics, we use a wide range of industry-approved technologies and methodologies to deliver accurate, reliable utility mapping surveys in line with PAS 128:2022.
The main techniques include:
- Ground Penetrating Radar (GPR):
GPR is a non-invasive method that uses radar pulses to image the subsurface. It’s effective at detecting both metallic and non-metallic utilities and provides a cross-sectional view of buried features and utilities.
Ideal for: Plastic pipes, ducts, voids, and concrete-encased utilities.
Benefits: Works in areas where EML fails, such as concrete slabs or plastic utility pipes.
- Acoustic Location Methods:
Acoustic techniques involve transmitting sound waves into the ground and listening for reflections or changes. These are sometimes used to pinpoint pressurised water leaks or trace difficult-to-locate utilities and buried services.
Ideal for: Water pipe tracing, leak detection.
Limitations: Less commonly used and more situational.
- Electromagnetic Locators (EML):
Electromagnetic location is one of the most widely used techniques for detecting utilities such as electric cables and metal pipes. A signal is applied using a transmitter, and a receiver is used to trace the path and depth.
Ideal for: Metal pipes, electrical cables, telecom lines.
Limitations: Cannot detect non-metallic or poorly conductive utilities (e.g. plastic water pipes).
- Vacuum Excavation
Vacuum excavation (also known as suction excavation) is used to verify the exact position and depth of utilities. This method safely exposes underground services by removing soil through a suction hose without damaging the utility.
Ideal for: Achieving PAS 128 QL-A accuracy level.
Benefits: Minimises the risk of a utility strike during verification.
- Topographical Integration:
Utility data is typically combined with a topographical survey to accurately show the position of utilities relative to ground-level features, site boundaries, and structures. This integration is essential for planning and BIM (Building Information Modelling).
What Are the Benefits of Underground Utility Surveys?
Conducting an underground utility survey offers numerous advantages, especially before breaking ground. Here are some key benefits:
- Reduced project planning time: Streamline your project timeline by clearly understanding subsurface utilities.
- Minimised risk: Reduce the chances of unforeseen issues during excavation.
- Health and safety compliance: Ensure adherence to health and safety regulations, safeguarding your team and the public.
- Confidence in excavation: Gain assurance in identifying ‘safe’ areas for excavation or the safest route for proposed utilities.
- Cost Efficiency: Prevents unexpected delays and costly repairs by identifying potential issues before construction begins.
- PAS 128:2022 compliance: Meet industry standards, avoid surprises and make better-informed decisions.
The Consequences of Not Using Utility Mapping Survey Data
Not obtaining accurate utility mapping data when commissioning, planning, managing, and carrying out works on or near underground services poses a significant risk.
- Injury or fatalities – striking underground utilities, such as electrical cables, gas pipelines, or water mains, can result in serious injuries or fatalities to workers and bystanders.
- Fire and explosions – damaging gas pipes can lead to leaks that may cause fires or explosions.
- Utility outages – Damaging water, gas, or electrical lines can disrupt services for many people, potentially impacting residential, commercial, and industrial operations. Cutting through telecommunication lines can lead to disruptions in phone and internet services, affecting businesses and emergency services.
- Project delays – Repairing damaged utilities can cause significant delays to the construction project, leading to increased labour and equipment costs.
- Contamination: Damaging sewer or chemical pipelines can lead to environmental contamination, affecting soil and water quality. Leaks from damaged pipelines can harm local wildlife and disrupt ecosystems.
To mitigate these risks, it is crucial to conduct thorough utility surveys using methods such as ground penetrating radar, and electromagnetic location devices, and procuring utility reports before commencing any excavation work.
Why Choose Technics for Your Utility Survey Needs?
At Technics, we recognise the critical importance of understanding the purpose of your survey from the outset. This understanding enables our team of experts to tailor methodologies in line with industry specifications, including PAS 128:2022, ensuring cost-effective solutions within your budget. With over two decades of experience, our team is adept at overcoming limitations to deliver thorough and precise results.
By choosing Technics, you can proceed with confidence, knowing that your project is supported by accurate and reliable subsurface data which will help you to minimise risks.
For more information on our services and to discuss your project needs, please contact the Technics team today at enquiries@technicsgroup.com.
