Green and brown field site redevelopment PAS:128 Survey

Green and brown field site redevelopment PAS:128 Survey

About This Project

Our client gained planning permission to redevelop a plot of land consisting of an old factory off a main road with fields at the back of the site. The project would entail building two tower blocks of flats, new access roads and significant landscaping. In order to begin construction, the client needed to know the location of the below ground services to safeguard teams digging onsite and to prevent unnecessary damage to existing infrastructure.


The client had been advised they needed a M4 PAS:128 survey, typically the most expensive of survey types, but they didn’t have the knowledge or understanding of the methods involved to undertake the survey, so they turned to Murphy Surveys.


Following a review of the site and consultation with the client, we devised a survey plan conforming to PAS:128 2014 with different levels of survey for different areas for the site.


  • A full M4 survey wasn’t required of the whole site so we proposed an M4P survey of the main road, where services were likely to be the most complex, and M3P and M2P survey around the old factory, with the former being used in key areas where required.


  • For the fields at the back of the site, we proposed to survey a 2m wide strip around the perimeter of the site, to locate services entering in line with an M1P survey, with additional GPR scans undertaken where existing records indicate services running through the fields, rather than a full survey.


All GPR survey works were to be undertaken using a massive array antenna and post processed in our offices by qualified geophysicists. This approach allows for a reduction in site time, due to the speed of collection and not needing to process the data onsite. Furthermore, the post processing of the data improves its interpretation, by resolving weak and intermittent signals, and analysing multiple targets. This allows us to gain a better understanding of areas of complex or more obscure utility networks. In addition, there is the added advantage of acquiring a digital record of what work was carried out in the field. The GPR data was analysed and, 2D and 3D CAD drawings were produced showing the locations of all detected services on site, their depths and key asset information.


By working closely with the client and fully assessing the site, we were able to provide a solution that would save the client money and safeguard the safety of their site teams during construction.


For more information on this project, please contact Andy Kitson at




  • Property
  • New build
  • Re-development of land

  • Survey Type

    Utility Survey


  • RD8000 Electro Magnetic Locator
  • TX10 transmitter and associated accessories
  • IDS Stream C - A massive array GPR with 34 antennas in two polarisations

  • Project Duration

    1 week


    2D and 3D CAD drawings


    Case Studies, Subsurface Mapping