Withybrook, England Project Date: 17-18 December 2013 Electro Scan Project Benchmark Presented to Severn Trent Services Birmingham, England Report Date: 14 January 2014 Soluons About CPS Environmental Tanker Jeng Surveys (cctv & electro scan) Cleaning Drain Repairs Planned Maintenance CPS Environmental (Nonghamshire, England) is a diversified sewer cleaning, inspec\on, and repair company. Working with Ant Hire Solu\ons LLC (Leeds, England), CPS Environmental is pleased to present this benchmark Electro Scan Project. CPS Environmental Head Office: Buckthorpe, Oxton Road, Southwell, Nonghamshire. NG25 0NH Tel: +44 0 1636 812161, Fax: +44 0 1636 691251 Website: www.cpsenvironmental.co.uk 1 About Withybrook Withybrook is a rural village and civil parish in the English county of Warwickshire with a populaon of roughly 230 people. The village is located in a valley just west of the old Fosse Way and forms part of the borough of Rugby. 2 Project Findings Soluons 3 Execu\ve Summary Project Objecve Withybrook is an area that has experienced persistent unexplained high flows. Having been televised on mul\ple occasions it was a good candidate to test the use of Electro Scan to see if the technology could add value to iden\ficaon and measurement of sources of infiltraon. Results • Electro Scan not only iden\fied a number of poten\al sources of infiltraon, not seen by CCTV, but provided an es\mated L/S defect flow, ±40% accuracy. • Electro Scan was able to inspect 100% of the lines (23 Sewer Mains + 1 Connec\on = 24). By comparison, prior CCTV inspec\on recorded six (6) Abandoned Surveys, unable to inspect an average of 29% of the pipe and missing 69% of the sources of infiltraon (p11). • Total Es\mated Leakage of the twenty-three (23) pipes inspected represents 791,187 34.66 l/s, with the seven (7) worst pipe contribu\ng 27.67 l/s eighty percent (80%) of the suspected infiltraon (p 9-10). Way Forward Given Electro Scan’s ability to rapidly (i.e. 10m/minute for ES-150 and 15m/minute for ES-300) iden\fy & quan\fy sources of infiltraon, it is recommended that Severn Trent considering the adop\on of Electro Scan for all pre- CCTV assessments and to require CCTV contractors to visually inspect all major Electro Scan defects as part of any subsequent CCTV survey. Furthermore, given Electro Scan’s ability to detect leaks to within 1 cm, a similar trial is recommended on post-rehabilitated lines, such as lining, point repair, and new pipe construc\on, where Severn Trent as previously relied on visual observaon to cer\fy project comple\on. 4 Findings & Conclusions 1. Quan4ta4ve InForma4on on Flow Poten4al – By Electro Scan – Provides Much More Accurate Conclusions Than Visual Observa4ons From CCTV Inspec4on • Total Es\mated Leakage of the twenty-three (23) pipes inspected represents 791,187 gallons per day or 34.66 liters per second (l/s), ±40% accuracy, assuming a 1foot (30.48cm) head and 1% or less pipe slope. • Seven (7) out of Twenty-Three (23) sewer mains are es\mated to contribute 631,504 gallons per day (27.67 liters per second) or eighty percent (80%) of suspected infiltraon into the survey area. • Two (2) Infiltraon Observaons on the same pipe segment were iden\fied (1-Infiltraon Dripping and 1-Infiltraon Seeping) on Pipe Segment From SP43843403 to SP43843301, with no observaons of Infiltraon Running or Infiltraon Gushing, represen\ng one (1) pipe of twenty- three (23) or 4% of the pilot area. • Electro Scan iden\fied 572 locaons of poten\al infiltraon totaling a leakage poten\al of 55.09 GPM (35.01 Liters Per Second). 2. CCTV Overlooked an Average oF 64% oF the DeFects in the Pipe Sec4ons Surveyed In extreme cases CCTV missed as much as 92.7% of the defects present in a pipe sec\on (Sec\on SP43845104 to SP43845103) 5 Findings & Conclusions Connued 3. Survey Abandonments Seriously Reduce Assessment Accuracy • Forty-two (42) Sewer Main Television Inspec\on Reports were Completed or Par\ally Completed. • Twenty-three (23) Main Line Segments and one (1) Service Lateral were 100% Completely by Electro Scan; ie. 100% of All Sewers Were Completely Surveyed, with Zero Abandoned Surveys. • Out of a total of Forty-Two (42) Television Reports, 23 of 42 - or 55% - of Televised Lines Were Reported as an Abandoned Survey. • Of the Twenty-Three (23) Lines Electro Scanned, CCTV Reported Six (6) - or 26% - Abandoned Surveys ranging from as limle as 1.24% to as much as 88% of pipe sec\on length len un-surveyed by CCTV due to abandonment. • For the six (6) lines that were televised and reported an ‘Abandoned Survey,’ reverse set-ups were aempted; i.e. CCTV aempted from both Upstream & Downstream Manholes, but 29% of the total pipe lengths were never evaluated. • Of the sec\ons of pipe NOT televised due to Abandoned Surveys, 26 Flow Defects (i.e. defects registering an es\mated resultant flow) were iden\fied by Electro Scan. • On average, those por\ons of the pipe sec\on NOT televised due to Abandoned Surveys contained 63% of the whole pipe length’s infiltraon poten\al, despite being only 29.44% of the pipe’s total length. 6 Findings & Conclusions Connued Those por\ons of the pipe which go 'un-surveyed' due to Abandoned Surveys, are cri\cal points of infiltraon poten\al and this a significant por\on of the assessment of a pipes cri\cality is missed when surveys are abandoned. By providing quan\tave data with 0 survey abandonments Electro Scan is much bemer suited to assess a pipe's cri\cality and infiltraon poten\al. Given that 55% of all CCTV surveys in this sub-basin reported abandoned surveys, a very significant amount of data is likely missing from the analysis of this por\on of the network. Electro Scan does not replace CCTV, as Electro Scan neither locates defects to a specific clock posi\on, or is able to iden\fy pipe sags or alignment problems. However, Electro Scan does confirm the limited use of television inspec\on to find sources of pathways to ground, i.e. infiltraon, automacally and without the drawbacks of visual observaons. By locang anomalies to the closest 1 cm (0.4 in) recording data at the rate of one (1) data point, every ¼ inch, i.e. every 14 milliseconds, Electro Scan can accurately locate and measure defects in non- conduc\ve pipes (e.g. asbestos cement, brick, clay, plas\c, reinforced concrete, resin, etc.) in accordance with ASTM F2550-13. Recommended uses of Electro Scan include the ability to: • Iden\fy and measure all sources of infiltraon from cracks, bad joints, and defec\ve service connec\ons, • Rank & priori\ze sewer mains and laterals that should be repaired, relined, or renewed, • Integrate with hydraulic modeling programs to re-calibrate model assump\ons based on its es\mated liters per second (l/s) of flow from defects, • Cer$fy point repairs, relining, and new construc$on to ensure that projects performed by third-party contractors are delivered without defects or leaks, prior to Acceptance. While Electro Scan may not be able to dis\nguish whether leaks are occurring at a service connec\on or internal to a service lateral, it will consistently iden\fy gaps allowing electrical current to pass from inside the sewer system to ground. 7 8 9 10 11 12 CCTV Surveys All CCTV Reports were completed in accordance with Severn Trent standards following the most recent published WRc guidelines for visual observaons. NOTE: Given the number of significant defects found by Electro Scan, it is recommended that all prior CCTV repor\ng for Withybrook be reviewed to determine consistency of observaons, and that Electro Scan defects be reviewed side- by-side with CCTV to determine whether observaons were either missed, obscured due to Debris or Fats, Oils, and Grease, or not able to be visually detected, i.e. at joints. 13 14 Electro Scan Surveys All Electro Scan Reports were completed in accordance with ASTM F2550-13 Standard Prac\ce for Locang Leaks in Sewer Pipes By Measuring the Variaon of Electric Current Flow Through the Pipe Wall. hmp://www.astm.org/Standards/F2550.htm 15 16 17 Withybrook Sewer Plan 18 Electro Scan Project Work Produc\vity What is Electro Scan? 1. What Does Electro Scan Do, That CCTV Cannot? Answer: Find sources of infiltraon and cracks. Infiltraon is a key factor causing Sanitary Sewer Overflows (SSOs) and Combined Sewer Overflows (CSO) caused by cracks & defects found in manholes, sewer mains, service connec\ons, and laterals. Given the limitaon of CCTV – i.e. not able to visually find leaks -- Electro Scan automacally finds , locates, and measures (i.e. in gallons per minute) the amount of infiltraon (i.e. in gallons per minute) caused by defects. Electro Scan can also cer\fy newly installed, recently repaired and rehabilitated pipe lining. 2. How Does It Work? Sewers are made of non-conduc\ve materials (e.g. asbestos concrete, brick, clay, cement, plas\c, reinforced concrete, etc.), so no electrical current should ever be able to “leak” or escape into the ground from inside the pipe – unless, of course, there is a crack or break in a pipe. Electro Scan’s patent-pending technology releases a focused array of low-voltage high- frequency electrical current that locates and quan\fies all defects. 3. Who Has Endorsed or Used Electro Scan? Electro Scan has been tested in Electric “Spikes” Show numerous U.S. EPA studies and found superior to CCTV in finding the locaon and Defect Locaons, Intensity & Es\mated quan\ficaon of defects that cause leaks.