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Appendix B 71 SO Overfill Valve in Tank Shut off Level Worksheet Important: This is meant to be supplemental worksheet and not a substitute to following the installation manual instructions. All length measurements are in inches. Please contact the Authority Having Jurisdic- tion (AHJ) and review local, state, and national codes to determine the regulatory requirements governing shut-off capacity in your region, as well as take into account other considerations such as extreme tank tilt. Take the following measurements with the valve in- stalled in the tank: Distance from the 71 SO inlet tube flange to the cast lug in the 71 SO body (see figures), upper tube length. Note: the Upper Tube Length must be at least 16" to in- clude the protective bend in the tube. WE Distance from the 71 SO inlet tube flange to the top and bottom of lower tube, valve length. W_ (U) _ Distance from the 71 SO inlet tube flange to the bottom of the tank. Note: If a tank bottom protector is present it may be necessary to add this thickness to dimension (OPW 6111 & 61 TP models add 0.6") (B) _ From the tank calibration chart provided by tank manu- facturer find the dipstick number (Y) which corresponds to the 100% volume. (Y) _ 1. To determine shut-off percentage: Subtract upper tube length (D) from distance to tank bottom (B) (X)=(B)—(D)-2"= Using the tank calibration chart provided by the tank manufacturer determine the tank capacity at the cal- culated (X) dimension and the 100% volume (Y) tank capacity. (X) tank capacity in gallons = (Y) tank capacity in gallons = SO% _ (X) capacity / (Y) capacity x100 = Note: The overfill valve must be installed per AHJ require- ments and all applicable local, state, and national codes. If the overfill valve is set above the allowable shut-off percent- age the overfill valve must be removed and replaced. For reference 40 CFR part 280 Subpart B Section 280.20 overfill valves should be set to a maximum of 95%. 21