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as there is a possibility of great pressure difference from this port.
Step six: Make sure the TE-5028A orifice is all the way open (turn the black knob counter clock-
wise). Record both manometer readings the one from the orifice and the other from the side of the
sampler. To read a manometer one side goes up and the other side goes down you add both sides, this
is your inches of water. Repeat this process for the other four points by adjusting
the knob on the variable orifice (just a slight turn) to four different positions and taking four different
readings. You should have five sets of numbers, ten numbers in all.
filter. Record the manometer reading from the side tap on the side of the sampler. This is used to
calculate the operational flow rate of the sampler.
Step eight: Record the ambient air temperature, the ambient barometric pressure, the sampler serial
number, the orifice serial number, the orifice Qactual slope and intercept with date last certified, today’s
date, site location and the operators initials.
An example of a Volumetric Flow Controlled Sampler Calibration Data Sheet has been attached with
data filled in from a typical calibration. This includes the transfer standard orifice calibration relationship
which was taken from the Orifice Calibration Worksheet that accompanies the calibrator orifice. The
slope and intercept are taken from the Qactual section of the Orifice Calibration Worksheet.
The five orifice manometer readings taken during the calibration have been recorded in the column on
the calibration worksheet titled Orifice H2O. The five manometer readings taken from the side pressure
tap have been recorded in the column titled Sampler "Hg.
The first step is to convert the orifice readings to the amount of actual air flow they represent using the
following equation:
Qa = 1/m[Sqrt((H2O)(Ta/Pa))-b]
where: Qa = actual flow rate as indicated by the calibrator orifice, m3/min
“H2O = orifice manometer reading during calibration, in. “H2O
Ta = ambient temperature during calibration, K ( K = 273 + C)
Pa = ambient barometric pressure during calibration, mm Hg
m = slope of Q actual orifice calibration relationship
b = intercept of Q actual orifice calibration relationship.
Once these actual flow rates have been determined for each of the five run points, they are recorded in
the column titled Qa, and are represented in cubic meters per minute. EPA guidelines state that at least