Application Note

smaller space like an office or
bedroom. Higher counts probably
mean the air handling system
isn’t properly balanced.
If a duct system branch is an
8-inch flex, it’s supposed to be
moving in the neighborhood of
160 CFM, and that translates to a
fairly low level of positive pres-
sure into the room even if the
system
is balanced....which
means that in a typical system
that employs a single central
return, the requirement of the
free flow of air at low resistance
back to the return register from
that room can be compromised,
leaving an even higher level of
contaminants in that space.
If you can measure those
contaminants, you would be able
to classify them (pollen vs. soot)
track their flow through the
building, and identify the source
—that’s a much more specific
service, with farther reaching
solutions, that you can now offer
customers.
2 Fluke Corporation Growing your business through indoor air quality particulate profiling
Step 1: How IAQ analysis and particulate
profiling fits into HVAC systems
space due to leaks and other
HVAC system malfunctions. And—
it’s not just return ducts. Duct
systems within the conditioned
envelope are just as susceptible
to IAQ issues.
IAQ inspections are built
on exactly that kind of HVAC
knowledge. Using your knowl-
edge of how HVAC systems are
designed—and how the design
can be compromised on installa-
tion—as well as where those
systems can break, will help you
track down where air quality
pollutants may be coming from.
On the flip side, air quality data
gives you the means to track
whether the HVAC system is
working the way it should.
For example: to determine
whether the duct system is
responsible for introducing con-
taminants, you’d conduct a
particle assessment at the supply
registers. It’s very evident at the
register whether the particulate
count is higher, especially in a
We all remember our fundamen-
tal facts related to air flow:
standard air at 70 °F (at sea level)
and 50 % relative humidity has a
weight of .075 pounds per cubic
foot. That means a typical 5-ton
cooling system moves 9,000
pounds of air in one hour, or up
to 216,000 pounds in a 24-hour
period.
These are more than just
impressive numbers for customers.
Consider something as simple
as a 10 % leak rate in the return
duct system (not uncommon in
residential) in an attic crawl
space. Now, consider the dust and
other particulate levels in that
crawl space. And, finally, imagine
the amount of particulates being
distributed throughout the ducts
in your customer’s home.
So, it’s not just door openings,
or air seeping in around windows
and other small openings that
affect indoor air quality. Dust and
other contaminants can be con-
stantly introduced into the living
Step 2: What tools do you need?
tak
ing particle counts. Multi-
channel refers to how many
different sizes of particles the tool
can measure. K
now
ing the
breakdown of particle sizes is
essential for you to diagnose
what
’s polluting customers
’ air
(mold particles are different sizes
than dust, for example), to trace
particles to their sourc
e, or to
verify that a fix has really less-
ened the count of particles.
Handheld is also an important
distinction, since some higher-
end models are meant to be
installed, for long term monitor
-
ing. As an HVAC technician, you’ll
get the most value from a hand-
held tool meant for onsite
inspections.
To conduct a complete IAQ inves-
tigation, you need to measure
temperature, humidity and partic-
ulates, at a minimum. That’s
b
ecause temperature and humid
-
ity can take a regular particle
count and magnify it times ten,
by g
iv
ing c
ertain c
ontaminants
like mold a welcoming environ-
ment. That makes hand held
multi-function and multi-channel
particle counters, such as the
Fluke 983, the most practical tool
for the job.
A particle counter senses,
sizes, and counts the particles
passing through it
. Multi-function
means the tool measures temper-
ature and humidity along with
0.005 0.05 0.5 5 500.010.1 110100 500
0.005 0.05 0.5 5 500.010.1 11010 0 500
Particle size in µm
Particle size in µm
Pollen
Mold Spores
House Dust
Bacteria
Animal Dander
Viruses
Carbon Black
(Photocopier)
Heavy
Dust
Settling Dust
Cement Dust
Fly Ash
Smog
Tobacco Smoke
Soot
Cooking Oil Smoke/Grease
Suspended Atmospheric Dust
Hair
(Human)