The new Publicly Available Standard from the British Standards Institute specifies the minimum that should be done in respect to underground utility detection, verification and location, and also provides guidance and pointers to best practice.
It sets out 4 types of survey: Desktop Study (Type D), site reconnaissance (Type C), detection (Type B), and verification (Type A).
The PAS supports both the practitioner and the client throughout the project cycle. At tender stage It is required for the practitioner to submit:
a) The survey type(s) to be deployed, including the extent for each type
b) For survey type B, detection methods to be deployed as specified in Table 2, including estimated extent for each method
c) Comment on these survey type(s) and, for survey type B, detection methods, with regard for satisfying the client’s requirements
d) Comments on the expected achievable quality level
e) Names and experience of the project team
f) How the survey area is to be managed to maximise the area available for survey and ensure the safe execution of the works
The client should then be able to compare apples with apples when seeking multiple quotes.
Following the work, the practitioner should submit a detailed report including:
• detailed survey outcomes including how successful each detection methodology proved to be and a plan showing any areas where these detection methodologies were not successful
• Utility segments identified with the quality level achieved
• Recommendation for any further survey work required to meet the client’s requirements
All recorded and processed data, site notes, metadata, and intermediate stage processing files shall be retained, and shall be available to the client on request
It is recommended as best practice for all data to be recorded as evidence of detections and of work undertaken. This is required where post processing has been specified. This is optional for other detection surveys – unless the client chooses to make it a requirement.
The practitioner needs to set out what they did and where, what the outcome was, i.e. what accuracy and confidence was achieved and what areas of uncertainty and risk remain. The practitioner should then stand by their deliverables.
If used properly by the client, the practitioner can no longer hide behind the ‘black box’ of complex geophysical equipment to explain away why something was missed or inaccurate in their survey output.
If adopted by the industry the PAS could enable:
• Clear definition for a minimum standard of utility verification and location
• More control to the client
• More comeback for the client when issues arise
• Fewer incidents related to service strikes
• Fewer delays caused by unknown buried services
Dr George Tuckwell