PAS128 setouts a robust methodology for Clients and Practitioners  to better inform on the location and and confidence of underground utility apparatus for any given project. PAS128 sets out the accuracy and expected confidence levels of the data captured for a PAS128 utility mapping survey.

Below are the Four Category types for a PAS128 Utility mapping survey, These range from CAT D – CAT A.

PAS128 – Desktop Utility Record Search
A complete search of all of the Utility asset owners whom may have utility assets with a specified search area. These are sometimes referred to as a C2 search

PAS128 Category C – Reconnaissance Search
Post collation of the Desktop utility search, the Utility record search data is compiled along with on site reconnaissance where utility street furniture and onsite observations are plotted to a best fit.

PAS128 Category B – Utility mapping Detection Survey
An on site Utility mapping survey utilizing multiple geophysical instruments to assess the Horizontal and vertical accuracy of the detected utilities. Quality levels 1 – 4 (QL1-4) would be assigned to each of the utilities detected.

PAS128 Category A – Verification Survey
Trial pits are completed to both verify the position and depth of utilities at predetermined positions along and/or around the site. Multiple techniques can be used including pot holing, hand dug trial pits, vacuum excavation and/or lifting of Utility apparatus to verify the the required data.

All PAS128 utility mapping surveys shall conform to the robust standards setout in BSI PAS128 2014 Specification for underground utility detection, verification and location