# Sruvey 123 - Hydrant Flow Testing

Discussion created by douglaswenning93 on Jan 29, 2018
Latest reply on Feb 1, 2018 by Philip.Wilson-esristaff

Hello.  I am new to Survey 123.  I would like to create a survey using the Collector app and Survey 123 for testing fire hydrant flows.  I would like to use Collector to select the hydrant, have it open Survey 123 so the inspector can add some information about the hydrant and the flow data (Static, Residual, and Pitot flow data) and then have the capacity calculated automatically by Survey 123.  This seems achievable but I am struggling getting the formulas to calculate the capacity and I fear it is something simple in the calculation that I am missing.

### HydGPM: Theoretical Discharge through Circular Orifices Formula

Computes a flow-rate in GPM given a psi and coefficient of the flow device.
Q = 29.84 x √P x D² x C or 29.84 x [(√Pitot) x (Diameter²) x (Coefficient)]
Q = flow-rate in GPM (Field = HydGRPM)
P = velocity pressure in psi (Pitot - measured at the hydrant in the field)

D = orifice diameter in inches (Diameter = 2.5 inches)
C = coefficient of flow device (Coefficient = 0.9)

### HydGPM_20: Equation for Determining Rated Capacity

Computes the flow-rate available at a specified residual
pressure (a.k.a. Rated Capacity). The example below enables
you to find the predicted flow-rate at 0 psi residual pressure.
Use this when fire flow testing hydrants.
QR(20) = QF x (HR0.54 / HF0.54) or QF x [(Static -20)0.54 / (Static - Residual)0.54]
QR(20) = Flow-rate predicted at the desired residual pressure in GPM
QF(20) = Total test flow-rate measured during test in GPM (QF = HydGPM calculated)
HR = Pressure drop from static pressure to desired residual pressure (Static – 20 psi) (Static measured in the field)
HF = Actual pressure drop measured during the test(Static – Actual Residual) (Static and Residual measured in the field)

I realize this is a big ask but I would truly appreciate any help with this.  I have attached several screen shots.

Thanks

Doug Wenning