Alicat Scientific FP-25 User manual

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FP-25 Flow Calibrator
for Particulate Air Samplers
& FP-25BT with Bluetooth
Operating Manual
The Fastest Flow Controller Company in theWorld!

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Thank you for purchasing an Alicat FP-25 or FP-25BT.
You are about to use the most advanced instrument available for calibrating
particulate air sampler ow rates. We know you are going to love your new
FP-25. If you have any questions about operating it, or if something is not
working as you had expected, please let us know. We are eager to help you in
every way we can.
Alicat Scientic, Inc.
[email protected]om • alicat.com
7641 N Business Park Drive Tucson, AZ 85743 USA
1-520-290-6060
Serial Number: ____________________________
Next Calibration: ___________________________
Recalibrate your FP-25 every year, in just 10 days.
Your calibration date is labeled on the back of the FP-25. Write that date in
the space above. We complete most calibrations within 10 business days of
receiving your device. When it's time for your FP-25's annual recalibration,
contact us by phone, email or live chat to set it up. Or, ll out the Service
Request Form at alicat.com/service.
5/22/2018 Rev.2 DOC-FP25MAN
All Alicat devices come with a NIST traceable calibration
certicate.
The Alicat FP-25 conforms to the European Union’s
Restriction of Use of Hazardous Substances in Electrical and
Electronic Equipment (RoHS) Directive 2011/65/EU.
The Alicat FP-25 complies with the requirements of the
Low Voltage Directive 2014/35/EU and the EMC Directive
2014/30/EU and carries the CE Marking accordingly.
The Alicat FP-25 complies with the requirements of the
European Union's Waste Electrical & Electronic Equipment
(WEEE) Directive 2002/96/EC.

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Welcome to the Alicat way.
You're busy, and the last thing you want to do is waste time wrestling with
your ow calibrator. We're here to make your life a little easier so you can do
what you do best. It's our pleasure to introduce you to your new FP-25:
• Detailed default SOPs give you an easy starting point to incorporate FP-25
SOPs into your air monitoring agency's guidelines, page 50.
• Calibrate any low-volume sampler, period. Laminar ow technology
makes your FP-25 just as accurate at 1 lpm as it is at 25 lpm, page 20.
• Direct Mode puts the FP-25 in the middle of the action, literally. Monitor
the ow conditions under the PM10 inlet without interference, page 16.
• Climb ladders less. Run BAM and TEOM ow calibrations from the comfort
of your shelter via Bluetooth communications (FP-25BT only), page 45.
• 1000 readings per second reveal oscillating ow rates. Take timed
measurements to smooth these out, page 27.
• Use it in any weather, from Anchorage to Miami. We've tested your FP-25
from -30°C to +60°C, and we have the sunburns to prove it.
• External temperature probe responds to ambient temperature changes
faster so your actual volumetric ow readings are always accurate, page 13.
• Any humidity, at any temperature.Your FP-25 is the rst ow calibrator
built with live RH sensing, keeping it accurate in high humidity, page 20.
• Backlit display with adjustable contrast is easy to read in direct sunlight.
Up at the crack of dawn? Press the Alicat logo to turn on the backlight.
• Monitor pressure during sampler leak checks. Internal pressure sensors
let you validate leak check results or troubleshoot problems, page 56.
• Change your STP to match any standard temperature and pressure
reference, or easily convert data to IMPROVE network references, page 35.
• Accidents happen, like your ow calibrator falling o the roof. We've
designed your FP-25 to survive drops, and likely still be in calibration.
• Sing in the rain. IP67 weatherproof connectors protect your FP-25 if it
starts to rain during your calibration.
• Charge it anywhere. A full charge powers your FP-25 for up to 12 hours. To
recharge, plug the micro-USB cable into any PC or power supply, page 12.
• Log data to your PC. Talk to the FP-25 serially using the USB connector to
capture all ow data for logging and analysis, page 38.
• Pack it your way. Keep everything connected, or take it all apart. The FP-25
hard case lets you store the device any way you want, page 9.
• Nerdy?We are, too. Read all about the FP-25's theory of operation,
including humidity, temperature, pressure and ow readings, page 20.

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Table of Contents
Quick-Start Guide ________________________________________6
Setup...........................................................................................................................6
Operation: FlowVerication.........................................................................................7
Operation: Leak Check PressureVerication.................................................................7
Maintenance and Care.................................................................................................7
Getting Started__________________________________________8
UnboxingYour FP-25 or FP-25BT .................................................................................8
StoringYour FP-25.......................................................................................................9
Getting to KnowYour FP-25.......................................................................................10
Connectors andFittings ....................................................................................10
TheFP-25Display.............................................................................................11
ErrorCodes .......................................................................................................11
ChargingYour FP-25 ..................................................................................................12
Connecting the ExternalTemperature Probe toYour FP-25........................................13
ConnectingYour FP-25 to an Air Sampler...................................................................14
Standard Mode connections toair samplers via the barb tting........................15
DirectMode connections to air samplers with 1.25" downtubes........................16
DirectMode connections for leak checks............................................................17
Understanding How the FP-25 Works __________________________18
Overview and Function in EPA Reporting...................................................................18
Theory of Operation...................................................................................................20
Gas Viscosity andRelativeHumidity .................................................................20
Probe vs Stream Temperature Readings ............................................................21
Ambient vsInternalPressureReadings .............................................................22
Actualvs StandardizedFlow Readings..............................................................23
Navigating and Customizing Your FP-25 ________________________ 25
FP-25 Menu Map .......................................................................................................25
Collecting Data in Standard Mode..............................................................................26
InstantDatain StandardMode.........................................................................26
AveragedData inStandard Mode .....................................................................27
Choosing Engineering Units from Standard Mode......................................................29
Collecting Data in Basic Mode or Direct Mode............................................................30
Menu.........................................................................................................................31
TaringYour FP-25.............................................................................................31
Reviewing Averaged Measurements..........................................................................32

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About.........................................................................................................................33
Basic Conguration Menu..........................................................................................34
ChoosingDevice Engineering Units fromthe Basic Conguration Menu.............34
Dening STP/NTPReferenceValues...................................................................35
Advanced Setup.........................................................................................................36
Sensor Setup..............................................................................................................37
Setting up the Real-Time Clock..................................................................................38
Setting Up Serial or Bluetooth Communications........................................................38
Conguring the FP-25 for Serial Communications......................................................39
Serial Communications____________________________________40
Setting Up Serial Communications.............................................................................40
SettingTime and Date Serially...................................................................................40
Serial Streaming vs Polling ........................................................................................41
Collecting Live Flow Data Serially...............................................................................42
Taking Averaged Measurements Serially....................................................................43
Quick Serial Command Guide.....................................................................................44
Bluetooth Communications (FP-25BT Only) ______________________45
Setting Up Bluetooth Communications......................................................................45
Using Alicat Connect™ withYour FP-25BT..................................................................47
Connecting Alicat Connect toYourFP-25BT.......................................................47
MonitoringInstant Datawith Alicat Connect ....................................................49
Collecting AveragedData with Alicat Connect ...................................................49
Standard Operating Procedures (SOPs) _________________________ 50
Verifying Ambient AirTemperature............................................................................51
Verifying FilterTemperature.......................................................................................53
Verifying Ambient Pressure........................................................................................55
Verifying Internal Pressure during Leak Checks..........................................................56
Verifying Flow Rates in Direct Mode...........................................................................59
Verifying Flow Rates in Standard Mode......................................................................63
Alicat FP-25 Field Performance Check Sheet______________________ 67
Troubleshooting Your FP-25_________________________________68
Maintenance and Recalibration______________________________ 75
Specications __________________________________________76
Mechanical Drawings _____________________________________77
FP-25 Graphical Quick-Start_________________________________80

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Quick-Start Guide
The Alicat FP-25 is a NIST-traceable ow, pressure and temperature calibration
standard. It provides accurate readings of both actual volumetric ow and
standardized (mass) ow from 25 lpm/slpm down to 0.1 lpm/slpm. Your FP-25
is weatherproof and is designed to remain accurate in air temperatures from
-30°C (-22°F) to +60°C (+140°F) and at any humidity level, 0-100% RH.
Setup
We've fully charged your FP-25 at the factory, so you can use it right away.
• Tare your FP-25. Before you connect the calibrator to an air sampler,
ensure that no air is owing through the device and select MENU > TARE.
Note: The FP-25 is sensitive enough to measure the lightest of breezes,
so ensure that one end is plugged before selecting tare.
• Choose your engineering units. In Standard Mode, you can touch
the button above or below any parameter to enlarge it in the middle of
the display. If you touch that same item a second time, you can change
the engineering unit for that parameter. You can select units for all of the
parameters at once by selecting MENU > SETUP > BASIC CONFIG > DEVICE UNITS.
• Set up your averaging timer. Select MENU > SETUP > BASIC CONFIG > AVG TIME to
set the duration of averaged measurements, from 1 sec to as long as almost
10 hours. The FP-25 will add 1000 measurements to the average for each
second.
• Connect the external temperature probe to the FP-25. When possible,
we recommend using the external temp probe when capturing ow readings.
Whenever the FP-25 is using the probe to provide readings, the word Probe
will ash on the right side of the display. When the temperature sensor that is
in the ow stream is used, Stream will ash on the right side of the display.
• Connect the FP-25 to your air sampler. Each of the FP-25 ttings has an
embedded face seal, so there is no need to apply Teon tape to the threads.
» If you are using a sampler that has a standard 1.25" diameter downtube,
or an adapter for this size, we recommend using the Direct Mode ttings.
Rotate the FP-25 display by selecting MENU > BASIC MODE > ROTATE. Connect
the larger downtube adapter to the right (outlet) side of the FP-25, and the
smaller PM inlet adapter to the left (inlet) side. Connect the FP-25 to the top
of the sampler downtube, or the PM2.5 cyclone if you are using one.Then
replace the PM10 inlet on top of the FP-25.
» For all other samplers, connect the included barb tting to the right
(outlet) side of the FP-25. Attach the included length of silicone tubing to
the barb tting on the FP-25 and the barb on your sampler.
(See diagrams on back cover.)

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Operation: FlowVerication
• Monitor live ow readings. In both Standard Mode and Basic Mode, you
can monitor live readings of ow, pressure and temperature by viewing the
Instant screen. Readings are updated in real time.
• Capture an averaged reading. Select START AVG in either mode to begin a
timed average. The averages update in real-time until the measurement time
is complete. In Standard Mode, you can highlight any parameter in the middle
of the screen, just as you did on the Instant screen.
• Tare your FP-25 before calibrating the next sampler. For best results, get
a fresh tare when you move the FP-25 to a new sampler. Select MENU > TARE.
Operation: Leak Check PressureVerication
You can monitor the sub-atmospheric pressures inside an air sampler during a
leak check using the FP-25's ow stream pressure sensors.
• Rotate the FP-25 display. Select MENU > BASIC MODE > ROTATE.
• Mount the FP-25 beneath the leak check adapter. If you are already in
Direct Mode, simply replace the PM10 inlet with the leak check adapter.
• Monitor live pressure readings. Line pressure readings are presented in
both absolute (e.g., PSIA) and gauge (e.g., PSIG) pressure units. Readings are
updated in real time when viewing the Instant screen.
Maintenance and Care
• All connections and seals satisfy IP67 requirements for ingress protection,
so your FP-25 will not be damaged if it rains unexpectedly.
• We have designed the FP-25 to withstand drops onto concrete from shed
rooftops. If dropped, your FP-25 will likely retain its calibration, but the best
practice is to verify correct ow readings against a known-good FP-25.
• Calibrate your FP-25 annually. Request an Alicat factory calibration at
alicat.com/service or by calling Alicat at 1-888-290-6060.
Quick-Start Guide

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Getting Started
UnboxingYour FP-25 or FP-25BT
Your FP-25 was shipped to you in its custom hard case, containing the items in
the packing list below. Please contact Alicat immediately if you nd that any
item is missing from your FP-25 shipping box.
Receiving Inspection
• FP-25 battery-powered ow calibrator for particulate matter samplers (with
ow body caps and connector plugs)
• External temperature probe with 6 feet of cable and M8 connector
• Bluetooth antenna with threaded SMA connector (FP-25BT only)
• ¼”NPT Direct Mode PM inlet adapter (1.25" OD) with face seal
• ¼”NPT Direct Mode downtube adapter (1.25" ID) with face seal
• ¼”NPT barb tting for ¼”hoses
• 5-foot length of ¼”ID x 7/16”OD silicone tubing
• USB cable, micro-B to type A, for communications and charging
• Universal 2.0A 100-240 VAC to 5 Vdc wall adapter with USB type A
connector and international plug shapes
• NIST-traceable calibration certicate
• User manual with sample SOPs for commonly-used particulate samplers
• Waterproof hard case with custom foam insert
Note: The FP-25 case also accommodates (but does not include)
additional user-supplied items, such as ow audit/leak check adapters.

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Storing Your FP-25
We shipped your FP-25 to you with all ttings unconnected, but the FP-25
case allows you to keep as much or as little of it connected as you like.
Getting Started
FP-25 and accessories in hard case, shown in their
original unconnected arrangement when packed
at the factory.
FP-25 in hard case, shown packed in its Direct
Mode conguration with temp probe connected.
The user-supplied inlet adapter may remain
connected to the silicone tubing when stored.
Silicone tubing (5 feet)
Leak check adapter
(user-supplied)
External temp probe
with 6-foot cable
Barb tting
PM inlet adapter
Downtube adapter
FP-25 ow calibrator
Power supply, USB cable,
Bluetooth antenna

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Getting to KnowYour FP-25
The Alicat FP-25 is a NIST-traceable ow, pressure and temperature
calibration standard for particulate matter air samplers used in ambient air
monitoring. It provides accurate readings of both actual volumetric ow and
standardized (mass) ow from 25 lpm/slpm down to 0.1 lpm/slpm. Your FP-25
is weatherproof and is designed to remain accurate in air temperatures from
-30°C (-22°F) to +60°C (+140°F) and at any humidity level, 0-100% RH.
Getting Started
PM inlet adapter Downtube adapter Barb tting
Connectors and Fittings
Direct Mode Adapters
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520-290-6060 Ph. 520-290-0109 Fax
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Type 3 Class 2 Black
7641 N Business Park Dr. Tucson, AZ 85743
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Rev. No. Description Date
1 Change inner bore from 1.252 to 1.255 6/2/ 2016
Power button (IP67 rated)
Micro-USB jack for charging and communications (IP67 rated)
Bluetooth antenna connector (FP-25BT only)
1/4" NPT process ports
Backlight on/o button
IP67 equilibration vent
LCD display
Softkey buttons
4-pin M8 jack for temperature probe (IP67 rated)

11
Getting Started
The FP-25 Display
The gure below identies the various features of the FP-25 display when it is
in Standard Mode (upright orientation) and displaying live ow data. Press the
large button with the Alicat logo to toggle the backlight on and o.
For more details, see the Menu Map on page 25 and the menu-by-menu
descriptions that follow it.
Standard Mode | Instant Data
Temp
+24.38
#C
RH 38%

LPM
RH 38%
Vol Flow
+16.667
Instant
MENU
+15.442
SLPM
+16.667
LPM
START
AVG
#C
+24.38
BARO
+704.0
MENU Enters the menu system
(page 31).
START AVG Begins an averaged
measurement (page 27).
Engineering unit for the
highlighted parameter.
Alternating display of:
• Battery level indicator and
charging status (page 12)
• Error messages (see below)
Alternating display of:
• Relative humidity (RH%)
• Temperature source:
Probe = external
temperature probe
Stream = internal
temperature sensor
LPM
Stream
LPM
Probe
Std Flow
+15.442
SLPM
RH 38%
Highlights standard (mass)
ow rate in the center:
Vol Flow
+16.667
LPM
RH 38%
Highlights volumetric (actual)
ow rate in the center:
Highlights temperature in
the center:
Baro Press
+704.0
mmHgA
RH 38%
Gage Press
-0.12
psiG
RH 38%
Abs Press
+13.50
psiA
RH 38%
Highlights pressure in
the center. Push a second
time to choose pressure
parameter:
Internal absolute pressure:
Internal gauge pressure:
Barometric pressure:
Error Codes
Analog-digital converter error: ADC
Pressure over range of device: POV
Temperature over range of device: TOV
Volumetric ow over range of device: VOV
Mass ow over range of device: MOV
Totalizer missed out of range ow: TMF
Front display is locked: LCK

12
Getting Started
Charging Your FP-25
We've fully charged your FP-25 at the factory, so you can use it right away.
Expected battery life of a fully-charged battery is 12 hours of continuous
operation when the backlight is o, or 8 hours when the backlight is on.
The battery indicator on the right side of the Main screen in Standard Mode
reects the relative battery level. When the battery indicator is completely
empty, only about 15 minutes of battery life remains. Please charge the FP-25
as soon as possible to maintain full device performance.
Charge the FP-25 using the supplied USB cable (micro-B to type A) or any
similar cable. You may charge the FP-25 using any USB outlet on a computer
or portable power supply, but charging will be fastest (approximately 3.5
hours) when connected to the supplied 2.0A power supply.
Your FP-25 may be used while it is charging. A small lightning bolt symbol ()
will appear to the right of the battery symbol while the device is charging. If
the battery has been fully depleted, you may need to charge the FP-25 for a
full minute before the device can be turned on.
Warning: If the device is left on until the battery can no longer power
it, the charge indicator will fall out of sync with the actual charge. The
device can be re-synced by fully charging the battery once.
Warning: The safe charging temperature range is 0° to +45°C. If
internal sensors detect temperatures outside of this range, the battery
will not charge.

LPM
RH 38%
Vol Flow
+16.667
Instant
MENU
+15.442
SLPM
+16.667
LPM
START
AVG
#C
+24.38
BARO
+704.0
95 – 100%
80 – 95%
50 – 80%
20 – 50%
5 – 20%
0 – 5%
Charging Indicator


13
Getting Started
Connecting the ExternalTemperature Probe toYour FP-25
We recommend using the external temperature
probe when capturing ow readings. Whenever
the FP-25 is using the probe to provide readings,
the word Probe will ash on the right side of the
display. When the temperature sensor that is in
the ow stream is used, Stream will ash on the
right side of the display. See "Probe vs Stream
Temperature Readings" on page 21 for details.
Connect the external temperature probe to
the FP-25 by aligning its 4-pin M8 connector
with the 4-pin M8 receptacle on top of the
FP-25. When properly aligned, the cable of the
temperature probe will pass over the power button. Push the connector in all
the way, and then tighten the locking collar on the connector to secure it.
LPM
Probe
Vol Flow
+16.667
Instant
MENU
+15.442
SLPM
+16.667
LPM
START
AVG
#C
+24.38
BARO
+704.0
Note: The M8 connector on the FP-25BT is angled so the temperature
probe cable can pass in front of the Bluetooth antenna when it is
connected. This also allows the FP-25BT to be stored in its case with
both the temperature probe and Bluetooth antenna still connected.

14
Connecting Your FP-25 to an Air Sampler
Your FP-25 has 0.25" female NPT ports on each end of its ow body and comes
with three adapters for ease in connecting it to your air samplers. Each of
the supplied ttings has an embedded face seal, so there is no need to apply
Teon tape to the threads.
Caution: Do not use pipe dopes or sealants on the process connections.
These compounds can cause permanent damage to the FP-25 should
they get into the ow stream.
You can mount or hold the FP-25 in any position, because it is internally
compensated for any changes to its orientation during use. This makes
possible Alicat's exclusive Direct Mode connection for pass-through
calibration of FRM and FEM samplers. When mounting the FP-25 in Direct
Mode, you can rotate the FP-25 display by selecting MENU > BASIC MODE > ROTATE.
The FP-25 is also unaected by vibrations, so you can rest the base of the FP-
25 on top of even a badly vibrating sampler without sacricing measurement
accuracy.
Getting Started |ConnectingYourFP-25toan Air Sampler

15
Standard Mode connections to air samplers via the barb tting
The Standard Mode of your FP-25 shows live ow readings that are oriented
in the same direction as the logo on the front of the device. In this mode, you
can use the supplied barb adapter and silicone tubing to connect to any air
sampler, big or small. When using the FP-25 in Standard Mode, you can rest its
base on top of the sampler or hold it in your hand.
1. Thread the supplied barb tting into the right (outlet) side of the FP-25.
Then t one end of the supplied silicone tubing over the barb.
2. Attach the other end of the tubing according to your sampler type:
• FRM or FEM sampler with a standard
1.25" downtube: Remove the PM10 inlet
from the downtube. Then attach the
sampler's ow audit adapter (also called
a leak check adapter) to the top of the
downtube (or PM2.5 cyclone, if used). Fit
the other end of the tubing onto the end
of the ow audit adapter's barb tting.
• Sampler with a larger downtube
(IMPROVE or URG-3000): Remove the
sampling inlet from the downtube. Then
attach the sampler's 1.25" downtube
adapter and the standard 1.25" ow audit
adapter (also called a leak check adapter)
to the top of the downtube. Fit the other
end of the tubing onto the end of the ow
audit adapter's barb tting.
• SASS or SuperSASS: Fit the other end
of the tubing into the individual lter's
sampling inlet port. The outside diameter
of the supplied silicone tubing is just
the right size to create a seal against the
inside surface of the inlet port.
• Sampler with a low ow rate (1-5 lpm): You may need to adapt the
smaller inlet diameter of the downtube to accommodate a minimum 0.25"
standard barb tting. Remove any screen that surrounds the inlet, and then
connect the inlet adapter to the other end of the supplied silicone tubing.
Getting Started |ConnectingYourFP-25toan Air Sampler

16
Direct Mode connections to air samplers with 1.25" downtubes
If you are using a sampler that has a
standard 1.25" diameter downtube,
or a sampler that includes an adapter
for this standard downtube size,
we recommend using Direct Mode,
because it most closely reects the
ow conditions during normal sampler
operation.
1. Prepare the FP-25 for Direct Mode
by selecting MENU > BASIC MODE and then
selecting ROTATE to rotate the screen.
2. Mount the FP-25 beneath the PM10
inlet.
2.1 If the FP-25 is not already
connected in Direct Mode, remove
the PM10 inlet from the downtube.
» Connect the larger downtube
adapter to the right (outlet) side of
the FP-25, and the smaller PM inlet
adapter to the left (inlet) side.
» Mount the FP-25 to the top of
the sampler downtube, or to the
PM2.5 cyclone if you are using one.
The downtube adapter of the FP-25
should t snugly over the downtube.
» Place the PM10 inlet on top of the
FP-25, sliding it over the end of the
FP-25's PM inlet adapter.
2.2 If you are already in Direct
Mode, replace the leak check adapter
with the PM10 inlet, sliding it over the
end of the FP-25 PM inlet adapter.
Caution: The FP-25 is optimized for use at near-atmospheric pressures.
Using this device under positive pressure is not recommended.
Using the FP-25 above 45 psig of internal line pressure, or 15 psi
of dierential pressure between the inlet and outlet, will result in
permanent damage to the internal pressure sensors.
Getting Started |ConnectingYourFP-25toan Air Sampler

17
Direct Mode connections for leak checks
If you are using a sampler that has a standard 1.25" diameter downtube, or a
sampler that includes an adapter for this standard downtube size, you may
also use Direct Mode to monitor the sub-atmospheric pressures inside the air
sampler when conducting leak checks.
1. Prepare the FP-25 for Direct Mode by selecting MENU > BASIC MODE and then
selecting ROTATE to rotate the screen.
2. Mount the FP-25 beneath the leak check adapter.
2.1 If the FP-25 is not already connected in Direct Mode, remove the
PM10 inlet from the downtube.
» Connect the larger downtube adapter to the right (outlet) side of the FP-
25, and the smaller PM inlet adapter to the left (inlet) side.
» Mount the FP-25 to the top of the sampler downtube or PM2.5 cyclone,
if used. The downtube adapter of the FP-25 should t snugly over the
downtube.
» Place the leak check adapter (ow audit
adapter) on top of the FP-25, sliding it over
the end of the FP-25's PM inlet adapter.
2.2 If you are already in Direct Mode,
replace the PM10 inlet with the leak check
adapter, sliding it over the end of the FP-25
PM inlet adapter.
Note: During leak checks in Direct Mode,
the FP-25 will provide ow readings in
addition to pressure readings, but these
are not comparable to any ow
readings reported by the sampler, other
than conrming a no-ow condition. Whereas the sampler is
measuring ow at the end of the ow path, the FP-25's location right
after the closed valve on the leak check adapter prevents it from
providing meaningful ow measurements during leak checks.
Getting Started |ConnectingYourFP-25toan Air Sampler

18
Overview and Function in EPA Reporting
The Alicat FP-25 is a NIST-traceable ow, pressure and temperature calibration
standard for particulate matter air samplers used in ambient air monitoring.
Particulate samplers used in US Environmental Protection Agency (EPA)
reporting must maintain consistent ow rates in order to keep their reports of
atmospheric particulate matter concentrations standardized and accurate.
The US Code of Federal Regulations (CFR), Title 40, Part 50 denes the national
standards for ambient air quality and their measurement methods. The Alicat
FP-25 ow, pressure and temperature calibrator has been designed to exceed
all EPA requirements for calibration of both PM10 and PM2.5 federal reference
method (FRM) ambient air samplers and their equivalents (FEM).
40 CFR Part 50, Appendix J for PM10 air sampling
40 CFR Part 50, Appendix J (Reference Method for the Determination
of Particulate Matter as PM10 in the Atmosphere) denes PM10 ow rate
calibration and verication procedures.
Paragraph 8.2.2 requires that the ow rate standard be NIST-traceably
calibrated such that its reported actual ow rate (volumetric ow) be accurate
to within 2% of reading over the expected operational range of ambient
temperatures and pressures.
40 CFR Part 50, Appendix L for PM2.5 air sampling
40 CFR Part 50, Appendix L (Reference Method for the Determination of Fine
Particulate Matter as PM2.5 in the Atmosphere) denes the PM2.5 ow rate
calibration and verication procedures.
Paragraph 9.2.2 requires that the ow rate standard be NIST-traceably
calibrated such that its reported actual ow rate (volumetric ow) be accurate
to within 2% of reading over the expected operational range of ambient
temperatures and pressures.
Paragraph 7.4.7 denes the air sampler' range of operational conditions
as -30°C to +45°C, 0-100% RH and 600-800 mmHg. We have designed and
tested the FP-25 to achieve 1% of reading ow accuracy across all possible
combinations of these operating conditions.
Understanding How the FP-25Works

19
EPA Quality Assurance Handbook, Vol. II
The EPA's Quality Assurance Handbook, Volume II (Ambient Air Quality
Monitoring Program), Section 12.1.3 (Table 12-1), requires that the standards
used for calibration of the air sampler's sensors be accurate to within 2% of
the NIST-traceable standard for ow rate, 1 mmHg for barometric pressure
and 0.5°C for temperature. These requirements and the corresponding FP-25
performance specications are summarized below:
Criteria EPA Acceptable Range FP-25 Specication
Flow rate ±2% of NIST-traceable
standard ±1% of reading of NIST- traceable standard
Pressure ±1 mmHg resolution
±1 mmHg accuracy
±0.1 mmHg resolution
±1 mmHg accuracy
Temperature ±0.1°C resolution
±0.5°C accuracy
±0.01°C resolution
±0.2°C accuracy
In addition to the above EPA-dened performance criteria, the FP-25 has been
designed to maintain 1% of reading ow accuracy across the entire operating
range of ambient particulate matter air samplers, dened as -30°C (-22°F) to
+45°C (+113°F), 0-100% RH and 600-800 mmHg.
Including the FRM and FEM air samplers noted previously, the FP-25 can be
used with the following types of air samplers and their associated ow ranges:
» FRM and FEM air samplers nominally operating at 16.7 lpm
» FEM air samplers nominally operating at 16.7 lpm with split ows at
1.0/15.7 lpm, 1.7/15.0 lpm, 2.0/14.7 lpm, 3.0/13.7 lpm or 1.7/3.0/12.0 lpm
» Carbon speciation samplers nominally operating at 22 or 6.7 lpm
» IMPROVE network PM samplers nominally operating at 22.8 lpm
» PM or black carbon analyzers nominally operating at 1-5 lpm
The FP-25 provides accurate readings of both actual volumetric ow and
standardized (mass) ow from 25 lpm/slpm down to 0.1 lpm/slpm.
Note: The FP-25 ships with a default STP (standard temperature and
pressure) of 25°C and 1 atm for standardized (mass) ow readings,
which matches the US EPA's standard. This STP reference can be
changed to correct to the IMPROVE network mean temperature (15°C)
or to overseas NTP (normal temperature and pressure, typically 0°C
and 1 atm). To make this change, select MENU > SETUP > BASIC CONFIG >
STP/NTP. See page 35 of this manual for details.
Understanding How the FP-25Works

20
Theory of Operation
Flow is generated by pressure dierentials. At its heart, the FP-25 measures
ow by monitoring those dierential pressures across an internal restriction,
similar to a Venturi ow meter. What sets the FP-25 apart is that the restriction
is a laminar ow element (LFE), which forces all of the airow into a laminar
(non-turbulent) ow regime. This property transforms the Venturi's quadratic
relationship between ow and dierential pressure (pressure drop across the
LFE) into a linear one.This linearity gives the FP-25 great accuracy across a
much wider ow range than is achievable in a Venturi ow meter.
The mathematical equation that reects this linear relationship is the Hagen-
Poiseuille equation:
Q=K∆P
η
Where: Q = actual volumetric ow rate
K = a constant based on the restriction's internal geometry
ΔP = dierential pressure across the LFE
η = absolute viscosity of air
Gas Viscosity and Relative Humidity
The equation above demonstrates the important role that gas viscosity plays
in determining ow rates through the FP-25. Because the actual viscosity of
a gas varies with changes in temperature (and pressure to a small degree),
the FP-25 continuously updates the viscosity value with live readings of ow
stream temperature and pressure.
The presence of water vapor in the air also has a signicant impact on the air's
viscosity, and this aects the accuracy of ow measurement through LFEs and
Venturis both. Your FP-25 is the rst ow meter to incorporate a live relative
humidity sensor within the ow path. The FP-25 uses this humidity data to
continuously update the viscosity value to provide accurate ow readings all
the way to 100% RH, at temperatures as high as 60°C.
Understanding How the FP-25Works