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Standard Operating Procedures (SOPs)
Verifying Ambient Pressure
1. Prepare the air sampler. Place your air sampler into Audit or Calibration
Mode following the instructions in the sampler's manual.
2. Prepare the FP-25.
2.1
Confirm that the FP-25 is displaying barometric pressure. When
the FP-25 is displaying barometric pressure, the word BARO will appear
above the pressure value at the top left of the screen in Standard Mode,
or to the right of the pressure value in Basic Mode. To view barometric
pressure, touch the button above the pressure
display in Standard Mode twice and select
Show baro pressure.
2.2
Confirm that mmHg is the displayed
engineering unit for barometric pressure. In
Standard Mode, you can verify the barometric
pressure units by pressing the button above
the pressure display just once to highlight
pressure in the center of the screen. The
engineering unit displayed to the right of the
pressure value should read mmHgA.
» To change the pressure engineering units, press the button above the
pressure display a second time to enter the unit selection menu. Select Set
button eng units to change the engineering unit on the display only. Select Set
device eng units to change the unit on the display and in the serial data frame.
Use the UP and DOWN keys to move the > cursor to mmHgA @ 0°C, and then
press SET.
Note: The FP-25 external temperature probe does not affect barometric
pressure measurements, so it may be either connected or disconnected
during ambient pressure verification procedures.
3. Verify the sampler's reported ambient pressure.
3.1
Verification or audit: Compare the sampler and FP-25 readings.
Is the sampler’s displayed ambient pressure reading within 10 mmHg of the
temperature displayed by the FP-25?
» If yes, perform the external leak check.
» If no, calibrate the sampler.
3.2
Calibration: Enter the FP-25 pressure value into the sampler.
3.3
Record your data.
mmHgA
Probe
Baro Press
+704.0
Instant
MENU
+0.000
SLPM
+0.000
LPM
START
AVG
#C
+24.38
BARO
+704.0