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63
Standard Operating Procedures (SOPs)
Verifying Flow Rates in Standard Mode
Note: This procedure is compatible with all air samplers.
Note: Perform all sampler temperature, pressure and leak checks
before verifying flow rates. Poor performance in any one of these areas
can be the root cause for bad flow readings during flow verification.
1. Prepare the FP-25.
1.1
Ensure that the external temperature
probe is connected to the FP-25. When
connected, the word Probe will flash on the
right side of the display, alternating with the
relative humidity value.
See "Connecting the
External Temperature Probe to Your FP-25" on
page 13 for details.
1.2
Confirm that LPM and SLPM are the displayed engineering units
for flow. If they are not, press the button
below the flow display you wish to change,
once to highlight flow in the center of the
screen, and then 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 LPM or SLPM, and then press SET.
Note: The FP-25 ships with a default STP
(standard temperature and pressure) of 25°C and 1 atm for
standardized (mass) flow readings, which matches the US EPA's
standard. This STP reference can be changed to correct to the IMPROVE
network mean temperature (15°C). To make this change, select
MENU >
SETUP > BASIC CONFIG > STP/NTP
. To use an NTP reference (normal
temperature and pressure, typically 0°C and 1 atm), simply select
NLPM as your engineering unit for mass flow.
1.3
If desired, set up the averaging timer. Select MENU > SETUP > BASIC
CONFIG > AVG TIME to set the duration of averaged measurements, from 1
second to as long as 10 hours. The FP-25 will add 1000 measurements to the
average for each second.
LPM
RH 38%
Vol Flow
+0.000
Instant
MENU
+0.000
SLPM
+0.000
LPM
START
AVG
#C
+24.38
BARO
+704.0