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Below please find our Sample Volume Calculators for both our Dry Gas Meter (DGM) and Rotameter based Gaseous Fuels Sampling Systems. Please select the appropriate calculator, then click “read more” above each blue box for helpful hints. If you need additional biogas or Renewable Natural Gas (RNG) support, please let us know and we’d be happy to help. 

Ohio Lumex Volume Correction Calculators

Dry Gas Meter Calculator

STP defined by ASTM as 60 °F (15.55 °C) and 14.696 psia

Temperature

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Final Temperature
Average Temperature

°C
Initial Temperature

While sampling, measure the temperature of the dry gas meter (DGM) at the beginning and the end of the sample run. Use the included thermocouple connection (Ohio Lumex Systems). Record these values below

Temperature Instructions

Pressure

Final Pressure
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Average Pressure

inHg
Initial Pressure

When sampling please use a barometer to measure atmospheric pressure in the environment. Record pressure at the beginning and the end of the sample run, then record the values below. NOTE: The barometric pressure reading may be obtained from a nearby National Weather Service station. If the station value is given as an absolute pressure, an adjustment for the elevation difference between the Station and sampling point has a rate of -0.1 “Hg per 100’ increase or +0.1 “Hg per 100’ for decrease. If the station value is given as a relative pressure (corrected to sea level), use the correction factors above, taking the difference between sea level and the elevation of the sampling point.

Pressure Instructions

Calibration Factor

Volume

Initial Volume

L

Final Volume

L

Measured Volume

L

Before beginning the sample run, record the initial volume indicated on the DGM. After the sample run, record the final volume indicated on the DGM. The total uncorrected sample volume is the difference between these two values. Record these values below in liters. The Calibration Factor is identified on the front panel of the sampling system if using an Ohio Lumex sampler. Each DGM has a different Calibration Factor denoted by “CF”. Record the CF value for the appropriate sample train below.

Volume Instructions

Gaseous Fuels meter control panel panel

Corrected Volume

L

The Corrected Volume is calculated only after all other measurements have been inputted

Rotameter Calculator

STP defined by ASTM as 60 °F (15.55 °C) and 14.696 psia

Pressure

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Initial Pressure
Average Pressure
inHg
Final Pressure

When sampling please use a barometer to measure atmospheric pressure in the environment. Record pressure at the beginning and the end of the sample run, then calculate the average. NOTE: The barometric pressure reading may be obtained from a nearby National Weather Service station. If the station value is given as an absolute pressure, an adjustment for the elevation difference between the Station and sampling point has a rate of -0.1 “Hg per 100’ increase or +0.1 “Hg per 100’ for decrease. If the station value is given as a relative pressure (corrected to sea level), use the correction factors above, taking the difference between sea level and the elevation of the sampling point.

Pressure Instructions

Temperature

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Initial Ambient Temperature
Final Ambient Temperature
Average Ambient Temperature
°C

While sampling, Measure ambient temperature at the beginning and the end of the sample run. Record these values below. Use the included thermocouple connection (Ohio Lumex Systems). Record these values below and calculate the average.

Temperature Instructions

Volume

Sampling Period
min

Methane Concentration

%
Measured Flow Rate
Lpm
Composition Correction Factor

Volume Instructions

Flow Rate and Time – During the sample run, you must constantly monitor the rotameter flow rate and ensure it is stable. Record the average flow rate. You must also record the sample duration in minutes. Methane Concentration – You will need to know the approximate methane concentration in the gas being sampled. Record this value below.

Rotameter Control panel

The Corrected Volume is calculated only after all other measurements have been inputted

Corrected Volume

L
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