Determine Meter K-Factor

for Flow Meter products

A meter K-factor is determined by dividing the total pulses generated by a flow meter by the known unit volume (e.g., gallons or liters) that passed through it during calibration, typically expressed as pulses/gallon or pulses/liter. This value is required to convert the pulses measured by the Eyedro Flow Meter into volumetric and flow rate units for presentation in the MyEyedro Cloud service.

Methods to Determine K-Factor

• Calibration Certificate (Recommended): The most accurate K-factor is provided by the manufacturer on the flow meter tag or calibration certificate, determined through factory testing. Occasionally these are marked on the meter register.
• On-Site Calibration (Volumetric/Gravimetric):
  1. Run a known volume of gas or fluid (V$$) through the meter.
  2. Count the total pulses (P) generated.
  3. Calculate K = Total Pulses (P) / Total Volume (V).

Key Considerations

• System Factors: Fluid viscosity, temperature, pressure, and pipe installation specifics can impact the K-factor.

K-Factor Calculation Procedure

1. Minimize flow of gas or water through the meter by turning off as many loads as possible. If possible, completely stop the flow.
   • Best accuracy is achieved if flow is zero (0) at the beginning of the process.
   • PRO TIP: If not possible to turn loads off, try starting at a period where there is naturally less volume.
2. Simultaneously:
   • Note the time
   • Take a photo of the gas/water meter register
   • Capture the cumulative pulse count from the Eyedro Flow meter.
3. Maximize flow of water or gas. Allow to run for a period of time.
   • Target between 400 and 1000 revolutions of the gas/water meter register. The higher the number the more accurate the calculation will be.
   • NOTE: Depending on the volume passing through the meter, this can be done over several days if necessary.
4. Minimize flow of gas or water through the meter by turning off as many loads as possible. If possible, completely stop the flow.
   • Best accuracy is achieved if flow is zero (0) at the end of the process.
   • PRO TIP: If not possible to turn loads off, try starting at a period where there is naturally less volume.
5. Simultaneously:
   • Note the time
   • Take a photo of the gas/water meter register
   • Capture the cumulative pulse count from the Eyedro Flow meter.
6. Compute the difference in meter register readings between photos 2 and 1. This is the total volume (V).
7. Compute the difference between pulse counts captured by the Eyedro Flow meter. This is the total number of pulses (P).
8. Calculate the K-Factor. K = P / V.
9. Enter the calculated K-Factor in the Pulse Monitor Settings plugin of MyEyedro.
   • K-Factor should be entered as the Units per Pulse parameter in MyEyedro.