Abstract
Buried utilities (e.g. gas, water, electricity, drainage), many installed decades ago, are vital urban support systems. Their locations are often not well documented, yet accurate location greatly helps replacement, rehabilitation and maintenance of existing services and is crucial for installation of new utilities: it minimises utility strikes / third party damage and the huge associated costs of delayed / additional streetworks. Several international standards and specifications aim to provide guidance on utility surveys to increase client confidence in their accuracy and repeatability. The most recent specification is PAS (Publicly Available Specification) 128 in the UK for underground utility detection, verification and location. This paper investigates the impact of PAS128 by comparing trial site survey results from different utility survey specialists with each other and with the vertical and horizontal accuracies at trial excavations. While the overall detection level was very good for all companies, the research revealed that the definition of quality level QLB1 needs to be reconsidered as it was not achieved in many places with respect to the vertical accuracy. It is recommended that future revisions of PAS128 differentiate between accuracy and confidence since detection by multiple sensing technologies increases the confidence, but not the accuracy as suggested by PAS128.
Highlights
A vast network of buried utilities exists underneath roads and pedestrian areas around the world, which need maintenance, rehabilitation and/or replacement. Najafi (2005) stated that more than 480 000 km of utility pipelines and cables are laid globally each year
Four geophysical survey companies provided comprehensive datasets resulting from a trial during a 9 d period in March 2015 to detect all buried assets on a small car park at the University of Southampton
Compliance with the PAS128 quality levels (QL) was assessed for the excavated assets
Summary
A vast network of buried utilities exists underneath roads and pedestrian areas around the world, which need maintenance, rehabilitation and/or replacement. Najafi (2005) stated that more than 480 000 km of utility pipelines and cables are laid globally each year. In contrast to the guidelines/standards in other countries, PAS128 goes further by requiring a minimum of two different techniques – usually ground penetrating radar (GPR) and electromagnetic locators (EML) – to be used for QLB (geophysical survey) and stating the horizontal and vertical accuracies for QLA and QLB. It introduced subQLs for QLB (see Table 1) depending on the number of different sensing technologies that detected the asset as well as the received signal strength. It is believed to be the first research of its type evaluating any of the survey standards across the world
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call