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975 AirMeter
Reference Guide Страница: 7

Fluke 975 AirMeter [7/32] Did you know

For more product information and detailed speciﬁcations, go to www.ﬂuke.com

Summary speciﬁcations

Feature Range Display

resolution

Accuracy

Measured speciﬁcations

Temperature -5 °F to 122 °F

(-20 °C to 50 °C)

0.1 °F

(0.1 °C)

± 0.9 °C/± 1.62 °F from 40 °C to 50 °C

± 0.5 °C/± 1.00 °F from 5 °C to 40 °C

± 1.1 °C/± 1.98 °F from -20 °C to 5 °C

Relative humidity 10 % to 90 % RH

non-condensing

1 % ± 2 % RH

(10 % RH to 90 % RH)

Air velocity 50 fpm to 3000 fpm

0.25 m/sec to

15 m/sec

1 fpm

0.001 m/sec

± 4 % or 4 fpm*

± 4 % or 0.02 m/sec* whichever is

greater

*Accuracy speciﬁcation only valid for

velocity readings above 50 fpm or

0.25 m/sec.

0 to 5000 ppm 1 ppm Warm up time 1 min (5 minutes for full

speciﬁcation)

2.75 % + 75 ppm

CO 0 to 500 ppm 1 ppm ± 5 % or ± 3 ppm, whichever is greater,

@ 20 °C and 50 % RH

Calculated speciﬁcations

Dew point

temperature

-44 °C to 50 °C

(-47 °F to 122 °F)

0.1 °C (0.1 °F) ± 1 °C when temp: -20 °C to 50 °C

RH: 40 % to 90 %

± 2 °C when temp: -20 °C to 50 °C

RH: 20 % to 40 %

± 4 °C when RH: 10 % to 20 %

Wet bulb

temperature

-16 °C to 50 °C

(3 °F to 122 °F)

0.1 °C (0.1 °F) ± 1.2 °C when RH: 20 % to 90 %

temp: -20 °C to 50 °C

± 2.1 °C when RH: 10 % to 20 %

Volume ﬂow rate

(in a duct)

0.01 M3/min

(1 cfm)

N/A

The volume ﬂow calculation will be a

simple average of the data points times

the duct area

% outside air

(based on

temperature)

0 to 100 % 0.1 % N/A

% outside air

(based on CO

)

0 to 100 % 0.1 % N/A

Making the numbers add up:

Understanding speciﬁcations

and performance of indoor air

quality test instruments

Air quality test

instruments must

deliver accurate

and verifiable per-

formance, both to

ensure precise and

reliable air quality

diagnosis, and to

provide credible

answers if results

or procedures are

challenged. The

air quality profes-

sional’s reputation

depends on the quality and perfor-

mance of the test tools in use, as well

as on their understanding of instrument

specifications, technologies, applications

and maintenance.

Read more about effectively measur-

ing airflow and other IAQ and HVAC

issues on www.fluke.com/iaq

Technician using the 975 AirMeter to

check for carbon monoxide leaks.

Odor (3%)

Too Dry (4%)

Too Humid (1%)

Noisy (3%)

Drafty (1%)

Too Hot (29%)

Too Cold (47%)

Smell (12%)

Adapted from: Federspiel, C.C. 1998. Statistical Analysis of Unsolicited Thermal

Sensation Complaints in Commercial Buildings. ASHRAE Transactions 104(1): 4, 8.

Just the facts:

•

77 % of occupant

complaints are due to

thermal conditions

•

Technicians will take

from 1.5 to 2 hours to

respond to and diag-

nose those complaints

Fluke 975 helps techni-

cians diagnose conditions

quickly and with fewer

tools. Do more. Carry less.

Common occupant complaints

Did You Know?

Application Note

Measuring air velocity with

the Fluke 975 AirMeter:

Using the velocity probe

F ro m t h e F lu k e D ig it a l L ib r ar y @ ww w .f l uk e .c o m/ li b ra r y

Air velocity is a key parameter in evaluating airflow sys-

tem performance. As part of basic testing, adjusting

and balancing of HVAC air distribution systems, most

HVAC technicians now use an anemometer to mea-

sure air velocity at grilles-registers-diffusers, within a

duct, or in open spaces.

Anemometers are typically very accurate tools,

especially at low velocities, but they must compensate

for air temperature, absolute pressure, and ambient

absolute pressure. The Fluke 975 AirMeter tool has an

accessory velocity probe that uses a thermal anemom-

eter to measure air velocity. A temperature sensor in

the probe tip compensates for air temperature, a sen-

sor in the meter reads absolute pressure, and ambient

absolute pressure is determined upon meter initializa-

tion. For users who prefer to calculate their own com-

pensation factors, the meter will also display air velocity

or volume at standard conditions.

This application note describes how to take accurate

air volume measurements within a duct, air measure-

ments at grilles-registers-diffusers, and other locations.

Air volumes within a duct

The ultimate goal of any duct

system is to move the required

air volume, while keeping all

other factors within acceptable

limits, and to deliver it in quanti-

ties and patterns that serve the

intended purpose: heating, cool-

ing, ventilating, exhausting, mix-

ing, humidifying, dehumidifying,

or otherwise conditioning the air

within a space. Velocity within

a duct is determined not only

by application, but also by how

the duct is designed. Key design

factors include: The level of

available static pressure that can

be overcome by the fan due to

friction losses and pressure drops

of devices within the air stream;

the cost of duct work; the space

available for duct work; and

acceptable noise levels.

To determine the air volume

delivered to all downstream ter-

minal devices, technicians use a

duct traverse. Duct traverses can

determine air volume in any duct

by multiplying average velocity

readings by the inside area of

the duct. Traverses in main ducts

measure total system air volume,

which is critical to HVAC system

performance, efficiency, and even

life expectancy. The difference

in air volumes between the main

supply duct traverse and the

main return duct traverse results

in outdoor air volume. A traverse

in run-outs is the most accurate

way to determine the air volume

delivered by the terminal device

(grille-register-diffuser). A tra-

verse in exhaust ducts reveals

exhaust air volume.

Measuring air velocity in a duct.

Fluke 975 AirMeter [7/32] Did you know

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