The avoidance of buried utilities for construction utilising ground penetrating radar - GPR Training

Duration

Minimum 6 hours learning.

GPR standard to be a minimum of 70% practical content.

Purpose/scope

The purpose of this standard is to provide the delegate with the theoretical and practical knowledge to locate buried utilities safely and effectively for the purpose of avoidance, preventing utility damage and increasing safety during excavation for the construction industry by utilising ground penetrating radar (GPR).

Scope:

• understand the need/requirement to avoid buried utilities prior to safe excavation using GPR and Electromagnetic Location (EML) technologies
• utilise recorded data and visual identification of buried services relevant to the proposed work/practical training area
• adhere to current guidance and in house or customer RAMS prior to safe excavation when using GPR
• have a sound understanding of ground penetrating radar data gathering theory and the possible limitations to data interpretation that differing ground conditions can create
• inspect, test, and calibrate the radar to the manufacturers required parameters
• complete an assisted and unassisted survey of the work area using grids, multiple and single scans
• interpret the data to successfully identify and highlight on the ground the presence and location of underground utilities for avoidance

Occupational relevance

Training delivered against this standard would be relevant to the following occupational group(s):

• Operative
• Supervision

Delegate pre-requisites

It is recommended that delegates have previously successfully completed the existing EML detection of buried services for construction training standard. If attended within 6 months of attending the GPR training standard, then the pre work training criteria need not be repeated.

Instruction/supervision

As a minimum, course trainers must be able to demonstrate that, in relation to this standard, they have:

• proven occupational experience and competence in using ground penetrating radar for utility location verification or utility surveying gained within the last 5 years
• successfully completed relevant manufacturers competence vetting process if available
• a verifiable CV
• a valid office of communications (Ofcom) OFW350 licence

Delivery

Delivery may be in an on or off the job environment.

All materials and equipment must be of an appropriate quality and quantity (minimum equipment 1:3) for delegates to achieve learning outcomes and must comply with relevant legislation.

The class size and delegate/trainer ratio (maximum 6:1 ratio) must allow training to be delivered in a safe manner and enable delegates to achieve the learning outcomes.

The following delivery methods may be used in the delivery of this standard:

• classroom
• external practical

This standard is considered to contain 70% or more practical training time.

This standard is set at a basic level.

Assessment

For the successful completion of training, delegates must complete an end of course practical assessment and knowledge test that measures all learning outcomes and has a pass or fail percentage.

Where this training is assessed using multiple-choice questions, a minimum of 20 questions must be asked and delegates are required to achieve an overall pass mark of at least 70% on both practical and written assessment combined.

Quality assurance

Assured

Quality assurance against this standard will require initial approval of the training organisation and their content mapped to the standard.

CITB will also conduct an approval intervention, either desk-based or centre visit, to ensure the training organisation can meet the requirements of the training standard.

Approved training organisations (ATOs) will be required to present information on records of training and assessment upon request to CITB for desk-based analysis. They will also be visited annually by the CITB quality assurance team

Renewal 

Refresher every 3 years

Buffer/ grace period

3 months

Classification

Mandatory Renewal

Approval date

September 2022

Review cycle

On request or 3 years from approval date

Learning outcomes

The delegate will be able to:

• explain the need/requirement of conducting utility avoidance surveys for construction
• delivery to include:
  • a brief overview of why there is a requirement to locate utilities prior and during excavation work. The prerequisite for this course is that the attendees must have completed the Detection for Buried Services for Construction course (EML)
  • GPR differences and benefits over EML and which technology is best suited for specific tasks, discuss which would be the best to be used
• assessment requirements:
  • demonstrate knowledge on above delivery aspects

• explain the need to obtain and use recorded and visual information about the proposed work area
• delivery to include:
  
  • origins of GPR
  • Ofcom licence and its requirements
  • utilising utility plans and visual reconnaissance of the proposed work area
• assessment requirements:
  • demonstrate knowledge on above delivery aspects

• operate within existing legislation and internal guidance/RAMS to work effectively and safely
• delivery to include:
  • an overview of the HSG47 and in House RAMS in relation to GPR
  • Ofcom licence and its requirements, to include the logging of use for Ofcom purposes
• assessment requirements:
  • check the work area for risks, utilities, possible issues for gathering data (restricted access, changing or challenging terrain). Confirm verbally and visually or by recorded tasks
  • cross reference utility drawings to the work area. Confirm verbally and visually or by recorded tasks
  • complete a log of use, to include as a minimum; the model number of the radio equipment, details of all locations at which the radio equipment is used, the date and duration of use for the radio equipment used, the type of use, and the frequency band used to operate the radio equipment

• demonstrate a good understanding of GPR theory and how ground conditions may affect the gathered data
• delivery to include:
  • how GPR works and how it can be useful in aiding utility location verification
  • antenna polarisation and the requirement for specific application techniques to aid utility location verification
  • how ground conditions can affect signal attenuation (strength) and its overall effect on the data results, depth, reliability, and usefulness
  • dielectric values of materials and how they respond to radar
  • how antenna frequencies affect data interpretation, depth penetration and data clarity
• assessment requirements:
  • demonstrate knowledge on above delivery aspects

• demonstrate the use of GPR to gather data about the buried infrastructure, highlight the presence of buried utilities for avoidance purposes within the designated practical area working within the functions/ parameters and specification of the equipment at hand
• delivery to include:
  • product overview features and any manufacturer recommended pre checks how it works in relation to radar theory i.e., encoder activation, acquisition speed, scans per meter etc.
  • data gathering techniques including unassisted and assisted (grid and/or GPS) scans
  • analysing the data results to evaluate its reliability and effectiveness by using the strength and quality of the reflections, depth penetration, possible scatter of signal and repeat reflections
  • overview of the data acquisition software and how to gather data, perform hyperbola fits (if available), import layers such as plans, maps, search engine maps (if available).
• assessment requirements:
  • equipment set up and manufacturers recommended checks (encoder calibrations, antenna checks, antenna positions etc). Confirm verbally and visually or by recorded tasks
  • software set up and familiarisation by performing some single scans to gather data to interpret and position possible targets. Recorded project on software and visual inspection by assessor
  • create an assisted (grid) survey, draw reference lines on the ground, gather data, interpret, and identify the location of utilities, perform hyperbola fits (if applicable), highlight position on the software (manually or by using software features if applicable), and mark the ground. Repeat if required to enhance skill and confidence. Recorded project on software and visual/photograph inspection by assessor
  • repeat the last task using GNSS if required. Repeat if required to enhance skill and confidence.
  • survey an area using single scans to identify the location of utilities and mark the ground and highlight on software (manually or by utilising specific software features)
  • repeat if required to enhance skill and confidence. Recorded project on software and visual/photograph inspection by assessor

• demonstrate through practical and question-based assessments a good understanding of the technology, the application theory and application techniques
• assessment requirements:
  • demonstrate knowledge on all the above delivery aspects
  • final assessment is a 20 multiple choice question paper

Additional information about this standard

A refresher is recommended if the delegate is an infrequent user of the equipment or a time exceeding 12 months has passed since utilising the equipment and the knowledge gained from attending the original training

HSE HSG47 https://www.hse.gov.uk/pubns/books/hsg47.htm 

• HSG47 states that detecting devices are to be used prior to excavation and the operators must have received thorough training in its operation. It lists GPR as an example of detecting products.

BSI PAS128 https://www.bsigroup.com/en-GB/standards/pas-1282022/ 

HSE PUWER https://www.hse.gov.uk/work-equipment-machinery/puwer.htm 

HSE HSWA https://www.hse.gov.uk/legislation/hswa.htm 

Ofcom OFW350 https://www.ofcom.org.uk/__data/assets/pdf_file/0025/55960/ofw350.pdf