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STP-MLD Line Leak Testing <br /> Note: To properly check a line leak detector the following is required: a graduated cylinder (usually graduated in <br /> milliliters) of approximately 300 ml volume, a test fixture which allows a leak of 3 GPH at 10 PSI (see Figure 1), <br /> and a stop watch or a watch with a seconds hand. <br /> 16. Turn the pump off at the load center, relieve the line <br /> pressure, and then remove the pipe plug in the <br /> shear-valve. Make adequate provision to trap any <br /> liquid that escapes to prevent environmental <br /> contamination. Install test fixture (pressure gage, <br /> leak valve and pressure valve) into the dispenser <br /> shear-valve port, see Figure 1. The test fixture will be <br /> used to introduce a 3 GPH leak @ 10 PSI. <br /> 17. With the leak valve closed, turn on the submersible <br /> pump at the load center and at the dispenser and <br /> look for leaks at the port of the shear-valve. <br /> Note: If there are any leaks, immediately shut the pump <br /> off at both the dispenser and at the load center, <br /> tag and lock out the breaker, and eliminate the <br /> leaks. Repeat step 17 to verify. <br /> 18. Turn the pump off at the dispenser and open both <br /> valves, draining the fluid into a suitable container, and <br /> observe the pressure dropping to zero. Continue <br /> draining until there is no more product coming out. <br /> Close the leak valve, turn the pump on at the <br /> dispenser and observe the pressure gauge. The <br /> pressure should increase quickly up to 20 to 26 PSI, <br /> and hesitate for 1-4 seconds or longer if there is air or <br /> vapor trapped in the system, and then increase to full <br /> Figure 1 pump pressure. <br /> 19. With the submersible pump on, adjust the leak valve and pressure valve simultaneously until 10 PSI and 3 gph or <br /> less are attained, while draining the fluid into a suitable container. To verify the leak, catch the output product into a <br /> graduated cylinder for 60 seconds (or the equivalent product measurement for a shorter time period, i.e., 94 <br /> milliliters at 30 seconds = 188 milliliters per 60 seconds). Turn off the pump and calculate the leak rate detected as <br /> follows: <br /> Leak Rate GPH = { (milliliters of fuel caught/ 60 seconds) x .95 } <br /> Note: The detected leak rate must be set to 3 GPH or less per EPA standards. If the leak rate needs to be adjusted, <br /> repeat step 19 while increasing or decreasing the leak rate and maintaining 10 PSI at the pressure gage. <br /> 20. Once the leak rate is established, do NOT adjust the leak valve. Open the pressure valve all the way and allow the <br /> line pressure to drop to zero. Leave the pressure valve open all the way. Continue to drain until there is no more <br /> product draining. Turn the submersible pump on at the dispenser and direct the fluid into a suitable container while <br /> observing the pressure gauge, which should not increase above 26 PSI. Turn the submersible pump off and wait at <br /> least one minute. Turn the submersible pump back on at the dispenser and observe that the pressure does not <br /> increase above 26 PSI. This step verifies the leak detector has detected a leak equivalent to approximately 3 GPH <br /> @ 10 PSI as required by the EPA. <br /> 21. Close the leak valve and observe the pressure increase to full pump pressure. Turn the submersible pump off and <br /> drain the pressure back to zero. <br /> 22. Turn the pump off at the load center, and remove the test fixture, and replace the pipe plug after applying UL- <br /> classified, non-hardening, non-toxic pipe thread sealant. <br /> 6 <br />