20
(X)
(Y)
(Z)
2
(C)
Appendix A
71SO Overfill Valve Upper Tube Calculation 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.
Desired
tank
capacity
for
shut-off:
SO%= _______
Dipstick Number on Tank Chart that corresponds to 100% volume (Y) =
Dipstick Number on Tank Chart that corresponds to SO% (X) =
Upper Tube Reference Number Z=Y-X
Upper Tube Depth Inside Tank C = Z-2”
Distance from top sealing surface for 71SO Lip
1
to inside the
top of Storage Tank
2
A=___________
For Non-Testable 71SO models only
In all cases for non-testable 71SO models, the top of the valve body must protrude at least 6 ½” into the tank to
provide a minimal clearance for proper operation.
3
Additionally the total Upper Tube Length must be at least 16”
of length to include the protective bend in the tube.
Is C less than 6 ½”
Yes / No
If
NO, Upper Tube Length (D)
= C + A
If
YES, Upper Tube Length (D)
= 6 ½ “+ A
Upper Tube Length
= ___________
For Testable 71SO models only
In all cases for Testable 71SO models, the top of the valve body must protrude at least 6 ½” into the tank to provide
a minimal clearance for proper operation.
3
Additionally the total Upper Tube Length must be at least 14 ½” of
length to include the protective bend in the tube.
Is C less than 5”
Yes / No
If
NO, Upper Tube Length (D)
= C + A – 1 ½ “
If
YES, Upper Tube Length (D)
= 6 ½” + A – 1 ½ “
Upper Tube Length
= ___________
1
Sealing surface may be the top of the Face Seal Adaptor, the built in sealing ledge inside some spill containers, or on non-
vapor tight applications the top of the pipe nipple
2
Some Underground Storage tanks utilize a manway system at the top. Make sure to use the top of the storage tank for
measurement and not to top of the manway. Consult your underground tank manufacturer for height of the manway
3
This measurement is taken from the seam where the upper tube is attached to the valve body to the inside of the tank top.
