Underground Utility Surveys

 PAS128:2014 is a publicly available specification issued by the British Standards Institution to provide guidance for: Underground Utility Detection, Verification and Location. 

 In short, PAS128 allows a buyer/Client to specify the type of survey they would like and the methodology by which it should be performed.

 There are four utility survey types specified within PAS128:2014 which are ordered by letter from D to A, with A being the highest quality.

Desktop Utility Records Search  

This survey is provided in the form of a report using record information obtained from utility service providers. 

This report shows their assets within the survey area identified (usually in a drawing format). This data is presented in the report in the from of drawings and relevant PDF documents. 

 Site Reconnaissance

This survey is in conjunction with a type D in which it also involves a site reconnaissance visit to identify physical features that support the existence of utilities within the requested area.

This is usually in presence of manholes, inspection covers, street furniture (i.e Lamp posts) and any previous excavation scar lines. 

This data is then presented as a record overlay onto a topographical survey or Ordnance Survey plan. 

Detection

Also accompanying a standard Desktop Search,  two geophysical techniques as a minimum are to be used when detecting utilities: EML (Electro Magnetic Location) and GPR (Ground Penetrating Radar). 

 The results obtained using geophysical techniques should be recorded and compiled with the data from the records search and the on-site reconnaissance. Results obtained using geophysical techniques should then be labelled as quality level: B.

Verification

This specification of Survey is the process of exposing a utility and subsequently measuring its accurate location, this can be achieved by lifting manhole covers or by excavating the utility through a trial pit.

Any service which has been verified in this way can be afforded the highest level of confidence 

verified and positioned by physical identification. 

 This page provides only a brief overview of PAS128:2014.

For more details, a copy of PAS128 is available to purchase from BSI at the following link: https://shop.bsigroup.com/ProductDetail/?pid=000000000030267400