Water Leak Detection Report

Transcription

1 Water Leak Detection Report Proof of Concept Client: Anglian Water Site 1: Somersham, Ipswich Site 2: Bramford, Ipswich Site 3: Caister, Great Yarmouth Engineer(s): J. Arnott, D. Williams, S. Welland Date of Survey(s): 28 th September 2017 & 3 rd October 2017 Date of Issue: 15 th November info@texodroneservices.co.uk Cert No

2 Contents 2 Contents 3 Summary 4 Methodology 4 Our Process 4 Health & Safety 4 Scope 4 Thermography 4 Personnel 5 Technical Specs & Environmental Information 6 Somersham, Ipswich 7 Image Set 2 8 Bramford, Ipswich 8 Image Set 1 9 Image Set 2 10 Image Set 3 11 Caister, Great Yarmouth 11 Image Set 1 12 Image Set 2 13 Image Set 3 14 Multispectral Capture 6 Image Set info@texodroneservices.co.uk 2

3 Summary It is almost inevitable that Proof of Concept investigations will produce both successes and failures. How these extremes are analysed and acted upon will ultimately determine the framework for moving this project forward. In this instance, both Anglian Water and Texo Drone Services found the site work to be very informative in understanding the needs, processes, limitations and aspirations for both sides. There is little doubt that remote sensing could have a vital role to play in the detection of mains water leaks. Certainly the advanced equipment and expertise that Texo Drone Services have available means that Anglian Water should be able to develop a realistic solution to such a costly problem. It is worth emphasising, that ongoing success should be measured in incremental steps as the refinement of technology and operational methods develop by the collaboration of both companies. Ray Faulkner PCN Category 3 ID No info@texodroneservices.co.uk 3

4 Methodology Our Process Scope Thermography The purpose of these trial days, was to provide Anglian Water and Texo Drone Services engineers the opportunity to combine their skills and experience to investigate the potential for using remote sensing equipment / drones to find mains pipe water leaks. Therefore, no prescribed process was adhered to, save for the normal H&S or SOP s followed in the deployment of drones. Several sites were identified by Anglian Water as either with the potential for water leaks or previously confirmed as a leak area. The aim of the exercise was to see if any correlation could be ascertained from the data gathered and known site conditions such that predictions for other leak sites could be confidently undertaken. Thus, at each site discussion would cover the most appropriate technique and how it should be implemented. Health & Safety In addition to the normal Risk Assessments and Method Statements (RAMS) prepared before a site visit, another process is also undertaken to ensure the safety, legality and appropriateness of using drones to facilitate the capture of aerial digital and thermal images. This process, undertaken as a desktop exercise, checks CAA Notams, flight-path restrictions and other potential hazards that may preclude the safe conduct of any flight. This procedure is then augmented on-site, where a visual inspection is combined with further assessment including radio frequency interference, kp index and GPS satellite locks. This survey and report combines images to provide a general thermographic and multispectral overview of three sites. Whilst care has been taken to record thermal images (thermograms) as accurately as possible, absolute temperature values obtained are of secondary value, as the qualitative relationship between different parts of the ground provides far more useful information regarding the potential for underground leaks. Variable environmental conditions, together with changes in camera angle, distance, material change and emissivity can all adversely affect the result. However, by combining images with equal parameters the relative change of temperature across selected areas will be accurate and therefore useful analysis can be made. From discussions prior to the survey, the following points have been incorporated into the methodology of data collection and presentation of findings: The survey is to include the general scanning and capturing of selected images that fairly represent the situation (qualitative survey). Anomalies noted to be identified either within the narrative or on the image. The survey is to be conducted in accordance with all CAA operator permissions, thermographic / multispectral camera specifications, environmental considerations and pre-agreed RAMS. Thermography (otherwise known as thermal imaging) is a specialist technique which uses thermal imaging cameras to capture infrared radiated wavelengths. When undertaking any survey, Texo Drone Services use specialist, purpose-built infrared camera cores with the highest detector sizes x available to the commercial market. In reference to digital cameras, this may initially be dismissed as a very low resolution, but it must be remembered that the data captured is equivalent to a thermometer in each cell; a total of 327,680 thermometers in every image. Several hundred individual images are often captured during the course of a survey, which can be stitched into panoramic thermograms or overlaid on a digital equivalent (orthomosiac). Personnel The following Texo Drone Survey & Inspection Ltd personnel were in attendance on-site: James Arnott Principal Systems Officer * Steve Welland Thermal Systems Manager (PCN Cat 1) * David Williams Principal Compliance Officer * * CAA Approved UAV pilots info@texodroneservices.co.uk 4

5 Technical Specs & Environmental Information These are recorded to ensure accurate data collection and an actionable final report. General Conditions (Somersham) General Conditions (Bramford) General Conditions (Caister) On-site risk assessment completed? Yes Survey Date: 28/09/2017 Survey Start: 10:30 Survey Date: 28/09/2017 Survey Start: 14:30 Survey Date: 03/10/2017 Survey Start: 10:00 Stabilized weather conditions and no cloud interruption during survey? Yes Survey End: 13:00 Air Temp. 18ºC Survey End: 16:00 Air Temp. 20ºC Survey End: 12:30 Air Temp. 12ºC Free from precipitation just prior to or during survey? Yes Wind Speed: 3.1 m/s Wind Speed: 4.1 m/s Wind Speed: 6.2 m/s Cloud Coverage: mostly cloudy Cloud Coverage: partly cloudy Cloud Coverage: scattered clouds Is the wind speed below 5m/s for thermal imaging? No* Long-wave Infrared Camera Specs Multispectral Camera Specs Short-wave Infrared Camera Specs Is the wind speed below 10m/s for UAV operations? Yes Spectral Range 7.5μm μm Spectral Bands B, G, R, RE, NIR Spectral Range 3.2μm - 3.4μm Resolution 640 x 512 (30Hz) Accuracy ±5 C Temperature Range -40ºC to 550ºC GSD Field of View Custom Bands 8cm - Pixel / 120m 47.2º HFOV 400nm - 900nm Resolution 320 x 240 Accuracy ±1 C Temperature Range -20ºC to 350ºC * As no temperature measurement was required, but rather the delta changes across a surface, this limitation was considered to be of minor consequence info@texodroneservices.co.uk 5

6 Somersham, Ipswich Image Set 1 Aerial Image Somersham Road Somersham Ipswich IP8 4NF Survey Image Grid Reference: TM X (Easting): Y (Northing): Latitude: Longitude: info@texodroneservices.co.uk 6

7 Image Set 2 Digital Image Raw Captured: 28/09/2017 It is very unusual to find naturally occurring straight lines within a thermographic image. The arrowed section above was noted during the flight and subsequently examined in more detail. The differential heating across the ground and trees is very small but continuous, thus confirming that no evidence existed to indicate any excess moisture in any part of this image. Thermal Image Raw Captured: 28/09/2017 Palette: Rainbow info@texodroneservices.co.uk 7

8 Bramford, Ipswich Image Set 1 Aerial Image Loraine Way Bramford Ipswich IP8 4JR Survey Image Grid Reference: TM X (Easting): Y (Northing): Latitude: Longitude: info@texodroneservices.co.uk 8

9 Image Set 2 Digital Image Thermal Image Thermal Image Raw Captured: 28/9/2017 Processed Captured: 28/9/2017 Palette: Inverted Rainbow info@texodroneservices.co.uk 9

10 Image Set 3 Enlarged Thermal Image Digital Image Zoomed Captured: 31/10/2017 Palette: Rainbow Visual Inspection Captured: 31/10/2017 The team were advised roughly where the mains water pipe should be running. This image represents a small area which appeared cooler and out of context to the surrounding vegetation. An inverted rainbow pallet was applied to the image and the span reduced to emphasise the anomalous area (circled above). The yellow pinpoints the centre of the leak with the effect extending into the red areas. This was indeed a known leak area and had previously been marked as such by Anglian Water, although not communicated to Texo Drone Services until after the survey info@texodroneservices.co.uk 10

11 Caister, Great Yarmouth Image Set 1 Aerial Image Pump Lane Great Yarmouth NR30 5BP Survey Image Grid Reference: TG X (Easting): Y (Northing): Latitude: Longitude: info@texodroneservices.co.uk 11

12 Image Set Digital Image Digital Image Thermal Image Zoomed ROI 1 : Area of thermally detected anomaly. Raw Captured: 31/10/2017 ROI 1 : Area of detected anomaly. Palette: Grey-scale info@texodroneservices.co.uk 12

13 Image Set 3 Thermal Image Thermal Image Raw Captured: 31/10/2017 Region of interest shown at a distance. Processed w/ Region of Interest Captured: 31/10/2017 Palette: Rainbow As part of the overhead scanning using thermal information, it was anticipated that mains water would appear as the coldest element within the image. However, other factors need to be considered such as the effect of shadowing. In the above image purple areas both below and to the right of the marked box show a similar temperature but equally are known to be dry. In this instance therefore, it can be concluded that no evidence exists to suggest a leak below ground info@texodroneservices.co.uk 13

14 Multispectral Capture This multispectral image has been processed using a standard NDVI formula originally devised to determine the health of vegetation. In this instance, it has been trialled to observe if localised excess water has contributed to plant growth. The red areas are roads, tracks or compacted ground where no green leaf (chlorophyll) matter exists. The green areas of the map highlight where there is healthy growth. The arrows indicate the areas of interest near the road, away from the influence of parked cars or other foreign objects, that ordinarily should have provided a consistent result. Despite the colour changes seen, there was no other evidence to substantiate any leaks and must be considered inconclusive info@texodroneservices.co.uk 14