PAS 128 Survey

With a constant demand for sustainable infrastructure in the UK, the BSI PAS 128 survey has been developed to provide greater confidence to clients in underground utility detection, maintenance and replacement.

What is the PAS 128 survey?

The PAS 128 specification is the result of a collaboration between industry experts, including the Chartered Institute of Civil Engineering Surveyors, HAHL, the Highways Agency and Transport for London. The aim isΒ to develop a robusPAS128_Front_covert specification for underground utility detection, verification and location.

The PAS 128 survey provides support to the client when conducting a specific survey type for increased accuracy and certainty, to enable them to plan effectively in all utility-based activities. Benefits include application to active, redundant or unknown utilities in both rural or urban areas, and utilities buried no deeper than three meters.

The following survey definitions will be used under PAS 128:

Level D – Desktop utility locating services

  • Identification of underground utilities via the collation and analysis of existing utility records
  • Both a stand-alone service and a pre-requisite for Levels C, B and A

Level C – Site reconnaissance

  • Supporting and validating existing records via visual inspection of physical evidence observed during a site visit

Level B – Utility detection using EML and GPR

  • Detection and utility location services using geophysical techniques, including high density array

Level A – Verification via intrusive inspection

  • Observation and location of underground utilities, using either a manhole/inspection chamber or physical excavation and exposure

How is PAS 128Β different from other specifications?

With a menu of survey types, detection methods, quality levels and geospatial locations, the PAS 128 survey provides detailed selection criteria to facilitate confidence in the data provided. It covers the project planning and scoping process, classification system for quality levels, desktop utility records search and detection, verification and location.

Previous utility mapping specifications have been subject to the interpretation of the practitioner. Whilst PAS 128 is voluntary, Technics has experienced a greater demand for transparency when planning for infrastructure projects. Therefore, our clients have welcomed the higher standards set by this underground utilities specification.

Technics can provide support

With collaboration in mind, it’s important to agree on the scoping of works at the planning phase of any project. With Technics’ suite of services and over 25 years’ experience, we can fulfil every element of PAS 128.


If you require any support on this process or you need a greater understanding of how to tailor your project to PAS 128, then please call our offices or email to discuss the survey further.