# Title 43

## SECTION 3175.10

### 3175.10 Definitions and acronyms.

§ 3175.10 Definitions and acronyms.(a) As used in this subpart, the term:

*AGA Report No. (followed by a number)* means a standard
prescribed by the American Gas Association, with the number
referring to the specific standard.

*Area ratio* means the smallest unrestricted area at the
primary device divided by the cross-sectional area of the meter
tube. For example, the area ratio (Ar) of an orifice plate is the
area of the orifice bore (Ad) divided by the area of the meter tube
(AD). For an orifice plate with a bore diameter (d) of 1.000 inches
in a meter tube with an inside diameter (D) of 2.000 inches the
area ratio is 0.25 and is calculated as follows:

*As-found* means the reading of a mechanical or electronic
transducer when compared to a certified test device, prior to
making any adjustments to the transducer.

*As-left* means the reading of a mechanical or electronic
transducer when compared to a certified test device, after making
adjustments to the transducer, but prior to returning the
transducer to service.

*Atmospheric pressure* means the pressure exerted by the
weight of the atmosphere at a specific location.

*Beta ratio* means the measured diameter of the orifice
bore divided by the measured inside diameter of the meter tube.
This is also referred to as a diameter ratio.

*Bias* means a systematic shift in the mean value of a set
of measurements away from the true value of what is being
measured.

*British thermal unit (Btu)* means the amount of heat
needed to raise the temperature of one pound of water by 1 °F.

*Component-type electronic gas measurement system* means an
electronic gas measurement system comprising transducers and a flow
computer, each identified by a separate make and model, from which
performance specifications are obtained.

*Configuration log* means a list of all fixed or
user-programmable parameters used by the flow computer that could
affect the calculation or verification of flow rate, volume, or
heating value.

*Discharge coefficient* means an empirically derived
correction factor that is applied to the theoretical differential
flow equation in order to calculate a flow rate that is within
stated uncertainty limits.

*Effective date of a spot or composite gas sample* means
the first day on which the relative density and heating value
determined from the sample are used in calculating the volume and
quality on which royalty is based.

*Electronic gas measurement (EGM)* means all of the
hardware and software necessary to convert the static pressure,
differential pressure, and flowing temperature developed as part of
a primary device, to a quantity, rate, or quality measurement that
is used to determine Federal royalty. For orifice meters, this
includes the differential-pressure transducer, static-pressure
transducer, flowing-temperature transducer, on-line gas
chromatograph (if used), flow computer, display, memory, and any
internal or external processes used to edit and present the data or
values measured.

*Element range* means the difference between the minimum
and maximum value that the element (differential-pressure bellows,
static-pressure element, and temperature element) of a mechanical
recorder is designed to measure.

*Event log* means an electronic record of all exceptions
and changes to the flow parameters contained within the
configuration log that occur and have an impact on a quantity
transaction record.

*GPA (followed by a number)* means a standard prescribed by
the Gas Processors Association, with the number referring to the
specific standard.

*Heating value* means the gross heat energy released by the
complete combustion of one standard cubic foot of gas at 14.73
pounds per square inch absolute (psia) and 60 °F.

*Heating value variability* means the deviation of previous
heating values over a given time period from the average heating
value over that same time period, calculated at a 95 percent
confidence level. Unless otherwise approved by the BLM, variability
is determined with the following equation:

*High-volume facility measurement point or high-volume FMP*
means any FMP that measures more than 200 Mcf/day, but less than or
equal to 1,000 Mcf/day over the averaging period.

*Hydrocarbon dew point* means the temperature at which
hydrocarbon liquids begin to form within a gas mixture. For the
purpose of this regulation, the hydrocarbon dew point is the
flowing temperature of the gas measured at the FMP, unless
otherwise approved by the AO.

*Integration* means a process by which the lines on a
circular chart (differential pressure, static pressure, and flowing
temperature) used in conjunction with a mechanical chart recorder
are re-traced or interpreted in order to determine the volume that
is represented by the area under the lines. An integration
statement documents the values determined from the integration.

*Live input variable* means a datum that is automatically
obtained in real time by an EGM system.

*Low-volume facility measurement point or low-volume FMP*
means any FMP that measures more than 35 Mcf/day, but less than or
equal to 200 Mcf/day, over the averaging period.

*Lower calibrated limit* means the minimum engineering
value for which a transducer was calibrated by certified equipment,
either in the factory or in the field.

*Mean* means the sum of all the values in a data set
divided by the number of values in the data set.

*Mole percent* means the number of molecules of a
particular type that are present in a gas mixture divided by the
total number of molecules in the gas mixture, expressed as a
percentage.

*Normal flowing point* means the differential pressure,
static pressure, and flowing temperature at which an FMP normally
operates when gas is flowing through it.

*Primary device* means the volume-measurement equipment
installed in a pipeline that creates a measureable and predictable
pressure drop in response to the flow rate of fluid through the
pipeline. It includes the pressure-drop device, device holder,
pressure taps, required lengths of pipe upstream and downstream of
the pressure-drop device, and any flow conditioners that may be
used to establish a fully developed symmetrical flow profile.

*Qualified test facility* means a facility with currently
certified measurement systems for mass, length, time, temperature,
and pressure traceable to the NIST primary standards or applicable
international standards approved by the BLM.

*Quantity transaction record (QTR)* means a report
generated by an EGM system that summarizes the daily and hourly
volumes calculated by the flow computer and the average or totals
of the dynamic data that is used in the calculation of volume.

*Reynolds number* means the ratio of the inertial forces to
the viscous forces of the fluid flow, and is defined as:

*Redundancy verification* means a process of verifying the
accuracy of an EGM system by comparing the readings of two sets of
transducers placed on the same primary device.

*Secondary device* means the differential-pressure,
static-pressure, and temperature transducers in an EGM system, or a
mechanical recorder, including the differential pressure, static
pressure, and temperature elements, and the clock, pens, pen
linkages, and circular chart.

*Self-contained EGM system* means an EGM system in which
the transducers and flow computer are identified by a single make
and model number from which the performance specifications for the
transducers and flow computer are obtained. Any change to the make
or model numbers of either a transducer or a flow computer within a
self-contained EGM system changes the system to a component-type
EGM system.

*Senior fitting* means a type of orifice plate holder that
allows the orifice plate to be removed, inspected, and replaced
without isolating and depressurizing the meter tube.

*Standard cubic foot (scf)* means a cubic foot of gas at
14.73 psia and 60 °F.

*Standard deviation* means a measure of the variation in a
distribution, and is equal to the square root of the arithmetic
mean of the squares of the deviations of each value in the
distribution from the arithmetic mean of the distribution.

*Tertiary device* means, for EGM systems, the flow computer
and associated memory, calculation, and display functions.

*Threshold of significance* means the maximum difference
between two data sets (a and b) that can be attributed to
uncertainty effects. The threshold of significance is determined as
follows:

*Transducer* means an electronic device that converts a
physical property such as pressure, temperature, or electrical
resistance into an electrical output signal that varies
proportionally with the magnitude of the physical property. Typical
output signals are in the form of electrical potential (volts),
current (milliamps), or digital pressure or temperature readings.
The term transducer includes devices commonly referred to as
transmitters.

*Turndown* means a reduction of the measurement range of a
transducer in order to improve measurement accuracy at the lower
end of its scale. It is typically expressed as the ratio of the
upper range limit to the upper calibrated limit.

*Type test* means a test on a representative number of a
specific make, model, and range of a device to determine its
performance over a range of operating conditions.

*Uncertainty* means the range of error that could occur
between a measured value and the true value being measured,
calculated at a 95 percent confidence level.

*Upper calibrated limit* means the maximum engineering
value for which a transducer was calibrated by certified equipment,
either in the factory or in the field.

*Upper range limit (URL)* means the maximum value that a
transducer is designed to measure.

*Verification* means the process of determining the amount
of error in a differential pressure, static pressure, or
temperature transducer or element by comparing the readings of the
transducer or element with the readings from a certified test
device with known accuracy.

*Very-low-volume facility measurement point or very-low-volume
FMP* means any FMP that measures 35 Mcf/day or less over the
averaging period.

*Very-high-volume facility measurement point or
very-high-volume FMP* means any FMP that measures more than
1,000 Mcf/day over the averaging period.

(b) As used in this subpart the following additional acronyms carry the meaning prescribed:

*GARVS* means the BLM's Gas Analysis Reporting and
Verification System.

*GC* means gas chromatograph.

*GPA* means the Gas Processors Association.

*Mcf* means 1,000 standard cubic feet.

*psia* means pounds per square inch - absolute.

*psig* means pounds per square inch - gauge.