Introduction: A review of available hand held laser scanning technologies has previously been undertaken by National Grid Gas Distribution reported in DNV GL technical note 14232.  This review identified that the hand held laser scanners may be of use for measuring and  recording damage to pipelines. This proposed scope of work is a follow on to this literature review to assess the identified devices fitness for purpose for the National Grid Transmission System.

Pipeline damage in National Grid Gas specification T/SP/P/11 is currently undertaken using a number of manual measurement tools by trained technicians.  For complex areas of damage it is time consuming to carry out the detailed measurements required to enable  the mechanical damage assessor to perform the required calculations.  In addition obtaining accurate measurements is made even more difficult due to access for example damage to the bottom of the pipe.  The damage is then recorded by means of taking  photographs and a rubbing of the damage and hand written results.

Fixed laser scanners (terrestrial laser scanners) have been used in the past to produce 3D models of pipework.  However, their use is  limited due to their accuracy and the required setup of the systems onsite.  Hand held laser scanners have been developed which  reportedly require minimum setup and provide greater accuracy than the terrestrial laser scanners.  The damage is recorded in a 3- diensionsal model which includes relevant measurements required to make an assessment of the damage. The use of these types of scanners has not previously been assessed to determine the suitability for assessing pipeline damage.

Objectives:

Assess the performance of hand held laser scanners for measuring damage to pipelines when compared to methods currently used in T/SP/P/11 and T/SP/P/20. If the assessment is successful, update of T/SP/P/11 and T/SP/P/20 to include hand held laser scanning methods for measurement of pipeline damage.

Expected Benefits: Complete assessment of hand held laser scanners to determine whether they are capable of measuring the damage within the tolerances specified in National Grid Gas specification for traditional measurement methods. The use of the hand held laser scanners reduce the time taken to carry out measurement of the damage and the accuracy.  In addition, if successful, this would reduce the exposure to risk of the P/11 technician with reduced time required in excavations to obtain the required measurements.