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Terms and conditions

UTILITY LOCATION SERVICES

 

  1. To establish the location of underground utility services Ground Scan NZ utilize Electromagnetic Location (EML) to identify conductive assets (and those laid with a tracer wire) and the latest Ground Penetrating Radar (GPR) technology to identify non-conductive assets.
  2. In keeping with our BeforeUDig Certification and training we utilise all available knowledge, resources, and best practise techniques to identify and trace all subsurface utilities within the area of works. We cannot however be responsible for obsolete/abandoned and therefore untraceable services.
  3. It is common for multiple services to be laid within a shared trench, duct or service corridor. While we will make every effort to identify and markout each utility, distinguishing individual services (particularly, but not limited to, non-conductive services using GPR) can be unachievable.
  4. In addition to the above, multiple conductive utilities laid in proximity can create a ‘masking’ effect, hiding one or cancelling out both signals. While our technicians are trained to look for and account for this anomaly, we cannot guarantee multiple services do not exist where only one has been marked. Therefore, we encourage all clients to exercise and maintain caution when performing any excavations. 
  5. While we aim to be as precise as possible, we work within the following industry accepted (AS4588) tolerance guidelines: +/- 300mm horizontal position, +/-500mm vertical position.
  6. Note the accuracy of depth measurement is subject to several factors outside of our control and is therefore meant as a guide only. Again, we encourage all clients to exercise and maintain caution when excavating. 
  7. Unless otherwise agreed, our standard Utility Location deliverables are colour coded surface spray markings of all services detected, alongside a PDF Field Report including an aerial/drone image of the site.
  8. Please note we will not know until we are on site what services we can detect with GPR. This will depend on the depth, material and diameter of the target line, plus ground conditions, all of which cannot be established until we are on site.
  9. Note that visual confirmation is the only method to guarantee positions of any underground utilities/assets/targets. Ground Scan NZ strongly suggest all located subsurface utilities are visually verified (to AS4588 standard QL-A) using safe excavation practises such as Hydro-Excavation.
  10. Unless otherwise stated, potholing and/or Hydro-Excavation to visually confirm service type and depth is not included in the stated pricing. If you require these services, please chat with our team as we would be happy to provide this service.
  11. Worksafe NZ has set minimum safe working practices for carrying out any work near underground utilities such as power, gas, water and telecommunications. You are encouraged to read this guide before performing any works. The guide can be downloaded for free by using the following link https://worksafe.govt.nz/topic-and-industry/excavation/excavation-safety-gpg/
  12. We apply for our own Utility Plans for planning purposes only, you will need to undertake your own checks prior to carrying out any excavation works. 
  13. Please note we are somewhat weather dependent – as heavy ground saturation can affect GPR.

 

UTILITY MAPPING (SURVEYING) SERVICES

 

  1. Ground Scan NZ will perform surveying services with reasonable skill and care.
  2. The Client must advise the required coordinate system and level datum prior to the survey. Changes requested after completion may incur additional costs.
  3. Ground Scan NZ’s surveyors are not licensed cadastral surveyors. While all care will be taken when surveying or locating boundaries, no liability is accepted for errors or inaccuracies.
  4. Survey data from located utilities is only as accurate as the quality level (QL) assigned to the utility location.
  5. Survey outputs will be provided in DWG and/or DXF formats (produced in Civil 3D). Other formats (e.g., 12d) remain the Client’s responsibility.
  6. Digital plans provided by the Client must be in DWG/DXF format. Ground Scan NZ will undertake reasonable checks but is not responsible for the accuracy of Client- supplied data.
  7. Machine control files prepared by Ground Scan NZ may only be installed under the supervision of Ground Scan NZ surveyors to confirm machine calibration. Ground Scan NZ is not responsible for machine calibration or for files created by others.
  8. RTK GPS generally achieves ±1–2 cm horizontal and vertical accuracy. Accuracy reduces with distance from the base station (approx. 0.5–1.0 mm per km) and may also be affected by obstructions or atmospheric conditions.
  9. Changes to plans/scope of the job take time to prepare and update in surveying equipment. Ground Scan NZ reserve the right to charge for this time.

LEAK DETECTION SERVICES

 

  1. We utilize the latest Acoustic Leak Detection Equipment. Though Acoustic Leak Detection is one of the most common and relied upon methods for detecting leaks in water supply pipes, detecting leaks acoustically is not without its limitations.
  2. There are several factors that can have an impact on the effectiveness of acoustic leak detection.
    • The material of the pipe and the diameter of it can have a big impact on how easily the leak can be detected. Leak signals travel the furthest in metal pipes and are weakened by plastic ones, making it difficult for vibrations to be picked up.
    • Additionally, larger pipes are much more difficult to detect leaks within than smaller ones are.
    • The soil around the ground can also impact the effectiveness of the system. Sandy soils tend to work better than clay soils or than on asphalt or concrete. Pipes that are below the water table can also be less easy to diagnose leaks.
    • Sometimes even the type of leak can have an impact on how easy it is to detect. Splits and corrosion pits in the walls of the pipes, for example, give stronger signals than leaks in joints or valves, making them easier to detect.
  3. While we endeavor to provide accurate Leak positioning, our conclusions and recommendations are intended as a guide only. 
  4. Note that visual confirmation is the only method to guarantee positions of any underground leaks.
  5. Our standard Leak Detection deliverables are colour coded surface spray markings of the line and leak location detected.
  6. Pot-holing and/or Hydro-Excavation to visually confirm leak location and depth is not included in our standard service. If you require these services please chat with us as we would be happy to arrange this for you.
  7. NZ Law & Regulations – Worksafe has set minimum safe working practices for carrying out any work near underground utilities such as power, gas, water and telecommunications. You are encouraged to read this guide before performing any works. The guide can be downloaded for free by using the following link https://worksafe.govt.nz/topic-and-industry/excavation/excavation-safety-gpg/
Ground Scan NZ

Waikato’s own Utility Location, Leak Detection and Subsurface Mapping service providers. Proudly offering complete coverage of the mighty Waikato!

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