The British standard PAS 128 which defines quality levels for the location of underground utilities was released in 2014. It is now up for revision. At Geo Business 2018 in London, Ian Bush of Black and Veatch, provided background to the PAS128 standard and identified the issues that have motivated the revision initiative.
The PAS process is a sponsored fast track specification managed and produced by the British Standards Institution (BSI). The PAS process requires 12 to 16 months from initiation to publication and follows rigorous rules specified by the BSI.
PAS128 is entirely the work of volunteers, but using BSI requires support. Historically, the development of the PAS128 standard for locating underground utilities was sponsored by many organizations in the UK including the Institution of Civil Engineers (ICE), Heathrow Airport Holdings, Highways Agency, Transport for London, National Joint Utilities Group, Ordnance Survey, University of Birmingham - School of Civil Engineering, the Utility Mapping Association and others.
PAS 128, which was aimed at practitioners not clients, was initiated in 2012 and went through 3 drafts. There was a high level of participation in the industry. The first draft got 508 and the second 685 comments. The final draft was published in 2014.It describes a hierarchy of quality levels similar to the American Society of Civil Engineers (ASCE) standard
- D Desktop utility record search - compiling and reviewing as-builts from utility anc telecom companies.
- C Site reconnaissance - visiting the site and indentifying relevant surface feature.
- B Detection - using ground penetrating radar and electromagnetic detection and possibly other remote sensing technologies. It also included an absolute precision B1 to B3.
- A Verification - using safe excavation tools on site to dig and find the utilities.
Ian said that the PAS128 standard has been very successful. Over 400 copies have been sold, which is exceptional for BSI publications which typically sell on the order of 200. It has been adopted by Hong Kong, El Salvador, and countries in the Middle East. But it needs updating to take advantage of new research such as the Mapping the Underworld and Assessing the Underworld projects and new detection and survey methods such as gyroscopic mapping.
It also needs to address some serious issues. It needs to provide guidelines for clients, the current standard is addressed to practitioners. The current standard assumed a 2D world. The revision needs to focus more on 3D and BIM. One of the major issues, whether to include post-processing of GPR scans, needs to be revisited. There are inconsistencies between the recently released PAS256 and PAS128.
To support the revision, which will again be performed by volunteers, Ian is looking for sponsors to fund the use of BSI and people to join the review panel.