Hydrostatic DP Level Transmitter (Head to Level)

P = 0.433 x SG x H (0.433 psi/ft is water at ~60 F), so level H = P / (0.433 x SG). A tap reading 4.33 psi in water is 10 ft; the full-span (URV) pressure for a 20-ft tank is 8.66 psi, so 4.33 psi is 50% of span. A denser fluid gives more pressure per foot, so the same 4.33 psi in a 1.2-SG fluid is only 8.3 ft. Assumes an OPEN (vented) tank with the tap at zero level, no elevation/suppression: an elevated dry-leg tap needs zero suppression and a wet-leg (sealed) tank needs zero elevation, both set at calibration, and the SG is at operating temperature. The transmitter's configured range and calibration and the tank geometry govern.

level_ft = measured_pressure_psi / (0.433 x specific_gravity); span_psi (URV) = 0.433 x specific_gravity x max_level_ft; level_pct = 100 x level_ft / max_level_ft. 0.433 psi/ft is water at ~60 F.

Hydrostatic (differential-pressure) level measurement (P = 0.433 x SG x H), by name; the transmitter's configured range/calibration and the tank geometry govern.

The hydrostatic head relation is public physics; the 0.433 psi/ft is water's density (62.3 lb/ft^3 / 144), the specific gravity and levels come from the fluid and tank, and the pressure is the transmitter reading.

Estimate. AHJ and licensed professional govern.

Field names used by the API: measured_pressure_psi, specific_gravity, max_level_ft, level_ft, level_pct, span_psi

• Hydrostatic head level = P / (0.433 x SG); 0.433 psi/ft = water at ~60 F; span = 0.433 x SG x max levelhydrostatics
• Open tank, tap at zero assumes a vented tank, tap at zero level, no elevation/suppression; a dry-leg needs zero suppression, a wet leg zero elevation; SG at operating temperaturelevel-transmitter calibration practice