Streamline - Spring 2013 - (Page 31)

Standard Operating Procedure for Using the Pressure Hold Method Leak Detection BY CHRISTOPHER B. CLARK, PE ALLEGHANY COUNTY DIRECTOR OF PUBLIC WORKS/ENGINEER As any water system operator will tell you, every system, no matter how old or new, will have its own particular considerations. OVER THE PAST few months, the Alleghany County Department of Public Works has been develop- ing a method to quickly locate water leaks. Using this technique, our department has been able to drastically reduce our water loss. The original idea came from discussions with Mr. Kenny Reynolds, a circuit rider for the Virginia Rural Water Association, who was aiding our leak detection efforts. The following is a step-by-step description of our method. Please be aware that this procedure is being refined as we continue to use it in the field. As any water system operator will tell you, every system, no matter how old or new, will have its own particular considerations. We offer this description as a framework only, and hope our experience will benefit other water systems. Please feel free to modify these procedures as you see fit. Using this method will require two employees who are familiar with the water system and have good maps. We recommend using two-way radios for communication instead of cell phones. Please notify us of any suggestions to make the process more efficient. Before starting a leak detection survey, you will need to locate all valves, hydrants, blowoffs, and meters in the area of interest. Study all available maps to make sure you understand, as best you can, how the system works. In Alleghany County, we have had to spend a significant amount of time (usually two-three days per area) using metal detectors, line locators, old maps, and other tools to find valves that have been paved over or buried, and, in some cases, have had to create new maps. Once you have located everything, you will need to decide how large or small an area you want to investigate. If you have a long section of waterline, you may be able test its entire length at once. A successful test may be achieved on a mile or less of pipe at one time, only if there are very few customers. However, if there are many customers, try to locate intermediate valves to perform the test on shorter sections of line. If no intermediate valves exist in such an area, consider placing new valves to facilitate this and future tests. This method also works well on short sections of waterline with variable line sizes (i.e. neighborhoods, dead end roads, under railroads, hard to access areas, etc.). If your testing area contains a hospital, large industrial and/or commercial customers, or schools, a successful test will only be achieved by good coordination with all affected parties. Those who perform the test need also to be aware of backflow preventers and fire service lines and systems in the area. Make sure that customers who have backflow preventers and fire systems know to check that their facilities are operating normally after the test. Failure to do so may result in a major loss of water, a flooded facility, activated alarms, and other complications. The best possible way to perform this test would be to turn off every meter; however, this is very time consuming and not practical for operators who have limited staff. The Pressure Hold Method: Locate all valves that affect your area of interest. 1 2 Locate a convenient fire hydrant. If no fire hydrant is available or has a problem such as a leak in the fittings or weep holes, use a meter setter by removing the meter and installing a pressure gauge in its place. See figures below for ideas on how to build your own. All testing 31

Table of Contents for the Digital Edition of Streamline - Spring 2013

From the President
From the Executive Director
What If?
Stormwater Management
Soapbox Farewell
Water and Wastewater Certifi cation Exam Test Taking Tips
Past 25 Years of VRWA
Proactive vs. Reactive
Asset Management and Drought Management
Is the Tank Contaminating the Water?
Committed to the Future of Rural Communities
Standard Operating Procedure For Leak Detection Using the Pressure Hold Method
The Virginia RATES Program is at Your Service
Ergs, Joules and Other Stuff
Employee Introductions
VRWA 25th Annual Exposition Agenda
Wastewater Math
eLearning Benefits
Do You Know What Your VRWA Benefi ts Are?
Membership Application
Throwing My Loop
VRWA Mailbag
Welcoming New Members
Training Calendar
Board Of Directors
VRWA Committees
Index To Advertisers/

Streamline - Spring 2013