What is a PAS 128 survey?

The PAS 128 specification was the result of a collaboration between industry experts and defines four survey categories that cover different quality levels. The aim is to develop a robust specification for underground utility detection, verification and location.

Listed below are the different level of surveys covered under PAS128:

Desktop utility records search (Type D)
Identification of underground utilities via the collation and analysis of existing utility records. Both a stand-alone service and a prerequisite for Levels C, B and A.
Supplied as a PDF document.

Site reconnaissance (Type C)
Supporting and validating existing records via visual inspection of physical evidence observed during a site visit to identify features that may indicate the presence of a service such as; manholes, valves, utility markers, street furniture and historic excavation scars. The deliverable will be in the form of a records overlay onto an existing topographical survey or OS base plan.

Utility detection using EML and GPR (Type B)
This survey is accompanied by a desktop utility report (survey type D). The detection survey is a non-penetrative survey conducted using at least two geophysical survey techniques. A consultation with the client during the quotation phase will identify the methodology used to conduct the survey. This is supplied as an AutoCAD file with a quality/confidence level assigned to all located services.

Verification via intrusive inspection (Type A)
This type of survey can complement a detection survey (survey type B). By visual inspection we can obtain further information to improve the confidence level about a particular service. Visual inspection of a service can be via access points such as manhole / inspection chamber or by its excavation and exposure.

If you are unsure of what level is required, please contact us to discuss your project.