Application Note

3 Fluke Corporation The multifunction Fluke 975 AirMeter™ tool is money in the bank for busy HVAC technicians
Percent outside air
The Fluke 975 can calculate
percentage of outside air using
either temperature or CO
2
differences between the return
air, mixed air, and outside air.
The Fluke 975 user selects “%
OUTSIDE AIR” and is prompted
for “CO
2
” or “Temp” calcula-
tions. The outside air value can
be measured by the AirMeter™,
or manually entered by the
user.
The greater the differential
between indoor and outdoor
temperature and CO
2
values,
the greater the accuracy
achieved. If the outdoor to
indoor temperature differential
is less than 20 °F, then a calcu-
lation based on CO
2
is likely
to be more accurate. ASHRAE
ventilation requirements for
most spaces at full occupancy
will result in a 700 ppm CO
2
differential between outdoors
and indoor occupied spaces.
(See ASHRAE standard 62.1
for commercial ventilation, or
AHSRAE standard 62.2 for
residential ventilation.)
Air velocity and volume
The Fluke 975 AirMeter™
tester’s velocity probe enables
the technician to measure air
speed and calculate the volume
of airflow. Air velocity and
volume are both key factors
that determine our ability to
condition, clean, heat, cool,
humidify, dehumidify, move
and otherwise handle and
control air quality.
The velocity probe contains
a thermal anemometer and
a compensating temperature
sensor that will telescope for
readings 33 inches beyond the
handle. Hot wire anemometers
are accurate through a wide
range of velocities, and are
especially preferred for low
velocity readings. The veloc-
ity range of the Fluke 975
AirMeter™ is 50 to 3000 fpm
(feet per minute) or 0.25 to 15
m/sec (meters per second). The
temperature sensor and the
absolute pressure determined
at meter startup compensate
the readings to actual condi-
tions.
“In a class of its own”
Added together, the capabili-
ties of the Fluke 975 AirMeter™
have placed the tool firmly on
Kevin Klockow’s must-have list.
“It’s kind of in a class of its
own,” says Klockow. “It reads
multiple things that no other
product out there really does.
Pricewise, you’re going to be
spending several thousand
dollars to duplicate those capa-
bilities, and you’re going to
have a bunch of tools to carry
around. This is one of those
tools that could take the place
of a lot of what you have.”
“Rest assured, I’ll be begging
for it. I would really like to
have one.”
Fluke Corporation
PO Box 9090, Everett, WA USA 98206
Fluke Europe B.V.
PO Box 1186, 5602 BD
Eindhoven, The Netherlands
For more information call:
In the U.S.A. [phone] or
Fax [phone]
In Europe/M-East/Africa [phone] or
Fax [phone]
In Canada (800)-36-FLUKE or
Fax [phone]
From other countries [phone] or
Fax [phone]
Web access: http://www.fluke.com
©2006 Fluke Corporation. All rights reserved.
Printed in U.S.A. 10/2006 2788393 A-EN-N Rev A
Fluke. Keeping your world
up and running.™