What is a PAS128 Survey Type B (Detection)?
As defined in PAS128 it is “The remote detection of underground utilities uses geophysical techniques. As the survey area is scanned, signals are received and analysed for anomalous responses. If the positions of these anomalies form linear strings they can be interpreted as features, such as utilities.”
This means that, unlike Survey Type D & C, Survey Type B can identify the location of utilities both horizontally and vertically within clearly defined accuracies based on methods of location used.
Why would I consider requesting a PAS128 Survey Type B?
Some of the main reasons for undertaking Survey Type B are:
A utility survey team will visit site; they will have with them all owner provided utility information (Survey Type D) and equipment to carry out a full site utility detection. PAS128 specifies that there are two minimum techniques for geophysical locating of utilities. These are:
Both techniques (when used on their own) have limitations but combined they give a far greater chance of accurately locating any utilities within site area.
All traced utilities are marked up on site and recorded using GNSS and total station for accurate mapping of utilities.
All detected utility segments will be given a quality level up to QL-B1P following PAS128 format.
All utility survey data will be presented in digital model format to clients specified requirements and will have a supporting utility survey report which will include methods of detection used, any concerns about individual utilities that may require further investigation, overall summary of all site findings and where possible photographic site evidence to support survey findings.