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Appendix B <br /> 71 SO Overfill Valve in Tank Shut off Level Worksheet <br /> Important: This is meant to be supplemental worksheet and not a substitute to following the installation <br /> manual instructions. All length measurements are in inches . Please contact the Authority Having Jurisdic- <br /> tion (AHJ ) and review local, state, and national codes to determine the regulatory requirements governing <br /> shut-off capacity in your region , as well as take into account other considerations such as extreme tank tilt . <br /> Take the following measurements with the valve mm <br /> stalled in the tank: <br /> Distance from the 71 SO inlet tube flange to the cast <br /> lug in the 71 SO body (see figures ), upper tube length . <br /> Note : the Upper Tube Length must be at least 16° to in- <br /> clude the protective bend in the tube . <br /> ( D) _ <br /> Distance from the 71 SO inlet tube flange to the top and <br /> bottom of lower tube, valve length . ( D) <br /> (W) = Upper <br /> (U ) = Tube <br /> Distance from the 71 SO inlet tube flange to the bottom _ <br /> of the tank. Note: If a tank bottom protector is present it <br /> may be necessary to add this thickness to dimension <br /> (OPW 6111 & 61 TP models add 0 .6") (W) Valve <br /> ( B ) = Length, <br /> bottom of <br /> From the tank calibration chart provided by tank manu - cut <br /> facturer find the dipstick number (Y) which corresponds <br /> to the 100% volume , ( B) <br /> (Y) = To Tank <br /> (Y) <br /> 1 . To determine shut-off percentage : Tank <br /> Subtract upper tube length ( D) from distance to tank (U) Valve Chart <br /> bottom ( B) Length, 100% <br /> (X) _ (B) — ( D ) - 2 " = top of cut Volume <br /> Dipstick <br /> Using the tank calibration chart provided by the tank <br /> manufacturer determine the tank capacity at the cal - <br /> culated (X) dimension and the 100% volume (Y) tank <br /> capacity. <br /> (X) tank capacity in gallons = <br /> (Y) tank capacity in gallons <br /> SO% _ (X) capacity / (Y) capacity x100 = <br /> Note: The overfill valve must be installed per AHJ require- <br /> ments and all applicable local, state, and national codes . If <br /> the overfill valve is set above the allowable shut-off percent- <br /> age the overfill valve must be removed and replaced . For <br /> reference 40 CFR part 280 Subpart B Section 280 . 20 overfill <br /> valves should be set to a maximum of 95%. <br /> L 21 <br />