Air-Conditioning, Heating and
Refrigeration Institute
What is AHRI?
National trade association representing manufacturers of
more than 90% of North American produced central airconditioning, heating, and commercial refrigeration
equipment.
A major voice for the HVACR industry offering its members
a forum to solve common challenges and a variety of
services and benefits.
ARI merged with the Gas Appliance Manufacturers
Association (GAMA) in 2008 to form the Air-Conditioning,
Heating, and Refrigeration Institute (AHRI).
What does AHRI do?
Is one of the nation’s larger trade associations
– Representing 311 HVACR and water heating manufacturers
across 39 product sections
Promotes policies beneficial to industry
Represents the industry domestically &
globally
Establishes international standards
– Over 100 industry standards and guidelines
Administers rigorous certification programs
– 39 Certification Programs
Administers a comprehensive industry
statistics program
AHRI Member Profile
Our members manufacture:
– Central air conditioning and heating
equipment
– Water heating equipment
– Commercial and industrial air-conditioning,
heating, and ventilation equipment
– Commercial and industrial refrigeration
equipment
– Hydronic heating equipment
– Components for heating, air-conditioning,
and refrigeration systems
AHRI Technical Committee on Sound
The AHRI Technical Committee on Sound (TCoS) oversees the
development and maintenance of all AHRI sound testing, rating,
and application standards.
The TCoS establishes and administers all AHRI policies on
acoustical activities.
Its members participate in pertinent sound standards writing
activities of other organizations.
The TCoS provides assistance and advice to AHRI’s product
sections on all acoustical issues.
AHRI Technical Committee on Sound
AHRI test setup and calibration sound standards include:
– ANSI/AHRI Standard 220-2012, Reverberation Room Qualification and Testing
Procedures for Determining Sound Power of HVAC Equipment;
– AHRI Standard 230, Sound Intensity Testing Procedures for Determining Sound
Power of HVAC Equipment;
– ANSI/AHRI Standard 250-2008, Performance and Calibration of Reference Sound
Sources;
AHRI product specific sound standards include (15):
– ANSI/AHRI Standards 260 (I-P)-2012 and 261(SI)-2012, Sound Rating of Ducted Air
Moving and Conditioning Equipment;
– AHRI Standard 350-2008, Sound Performance Rating of Non-Ducted Indoor AirConditioning Equipment.
– ANSI/AHRI Standard 575-2008, Method of Measuring Machinery Sound Within an
Equipment Space Proposed;
– AHRI Standard 885-2008 with Addendum 1, Procedure for Estimating Occupied
Space Sound Levels in the Application of Air Terminals and Air Outlets;
– Proposed AHRI Standard 1280P, Sound Performance Rating of Water Cooled
Refrigerating and Air-Conditioning Equipment.
AHRI Standards
All AHRI standards are available
for free download at:
– www.AHRInet.org
Air Handler Acoustics
Stephen Lind – Acoustics Engineer
La Crosse, WI
12-11-13
Air handling equipment makes noise
• To ensure proper acoustics in the space, you need
o Sound power levels as starting point for ASHRAE
Applications Handbook calculations
o Data per:
AHRI Standard 260 for ducted equipment
AHRI Standard 350 for un-ducted equipment
Why AHRI 260?
Application related acoustical components
Return Duct
Supply Duct
through
return
ceiling
breakout
supply
breakout
supply
airborne
Directly through
building structure
supply
breakout
return
airborne
supply
airborne
Application related acoustical sources/paths
Multiple noise sources (e.g.
supply fan & return fan, or
exhaust fan, compressor …)
Ducted
Inlet
Casing
Ducted
Discharge
Multiple paths (discharge, inlet, casing). Different attenuation on each path
duct casing
breakout radiated
supply
airborne
supply
breakout
supply
airborne
Need sound power of unit with all sources and all options accounted for along
all relevant paths. return
airborne
Fans – The Primary Acoustical Source
Fan Map: Sound is a function of the operating point
1500 RPM
9.0
Static Pressure, in H2O
8.6
1200 RPM
8.1
105 105
7.7
104 105 105
7.2
103 104 104 105 105
6.8
102 103 103 104 105 106
6.3
101 102 102 103 104 104 105 106
900 RPM
600 RPM
300 RPM
100 101 102 102 103 104 104 105
56%WO
5.4
99
100 100 101 102 102 103 104 105 106
91%WO
5.0
98
99
5.9
4.5
4.1
99
100 101 102 103 103 104 105 106
100 100 101 102 103 104 104 105 106
97
97
98
99
96
96
97
97
98
99
100 101 101 102 103 104 105 106 106
3.6
94
95
95
96
97
97
98
99
3.2
93
94
94
95
96
97
97
98
99
92
92
93
93
94
95
96
97
98
98
2.7
100 101 102 102 103 104 105 106
100 101 102 103 104 105 106 107
99
100 101 102 104 105 106 107
2.3
90
90
91
92
93
93
94
95
96
97
98
99
100 101 102 104 105 106 107 108
1.8
89
89
90
91
92
93
93
94
95
96
98
99
100 101 102 104 105 106 107 108 110
89
90
91
92
93
94
95
96
98
99
100 102 103 104 105
1.4
0.9
0.5
2
5
7
9 12 14 17 19 21 24 26 28 31 33 36 38 40 43 45 47 50 52 54 57 59 62 64 66 69 71
Fan Flow, kCFM
Empirical data required
In the unit per AHRI 260
1500 RPM
9.0
Static Pressure, in H2O
8.6
1200 RPM
8.1
105 105
7.7
104 105 105
900 RPM
600 RPM
7.2
103 104 104 105 105
6.8
102 103 103 104 105 106
6.3
101 102 102 103 104 104 105 106
5.9
5.4
100 101 102 102 103 104 104 105
56%WO
99 100 100 101 102 102 103 104 105 106
91%WO
5.0
98 99 99 100 101 102 103 103 104 105 106
4.5
97 97 98 99 100 100 101 102 103 104 104 105 106
4.1
96
96 97 97 98
99 100 101 101 102 103 104 105 106 106
3.6
94 95
95 96 97 97
98 99 100 101 102 102 103 104 105 106
3.2
93 94
94 95 96 97
97 98 99 100 101 102 103 104 105 106 107
2.7
92 92 93
93 94 95 96
97 98 98 99 100 101 102 104 105 106 107
2.3
90 90 91 92
93 93 94 95
96 97 98 99 100 101 102 104 105 106 107 108
1.8
89 89 90 91
92 93 93 94
95 96 98 99 100 101 102 104 105 106 107 108 110
1.4
0.9
89 90
91 92 93 94
95 96 98 99 100 102 103 104 105
0.5
2
5
7
9 12 14 17 19 21 24 26 28 31 33 36 38 40 43 45 47 50 52 54 57 59 62 64 66 69 71
Fan Flow, kCFM
300 RPM
AHRI 260 Components
Ducted discharge or
Ducted inlet
Free inlet
plus Casing
Casing
Throttle on
both sides
Throttle on non
tested side
Throttle on non
tested side
Measurement: Reverberation Room
Microphone
path
Ideally the sound is “the same” everywhere in the room...
... in real life there are variations. Follow AHRI Standard 220
to make sure variations are “small” enough.
We move the microphone and average to get a statistically
correct representative sample.
Sound Power from a Reverberation Room
Microphone
path
Measure sound pressure due to RSS (Known power per AHRI 250)
Determine power to pressure transfer function
Measure sound pressure due to unit
Determine power for unit
Each has a different acoustical signature
Fan arrays
Housed (FC or AF)
Belt drive plenum fan
Direct drive plenum fan
Coil
Filter
Appurtenances change unit acoustics
Opening
Longer
Lined
Lined
Plenum
Location
&
plenum
plenum
Size
Rest of
AHU
Octave Band Center Frequency (Hz)
50
40
8000
4000
2000
30
1000
8000
4000
2000
1000
500
250
125
30
60
500
40
70
250
50
80
125
60
90
63
Sound Power Level (dB re 1 pW)
DI unit
70
63
Sound Power Level (dB re 1 pW)
80
Base
Unit
Plenum
Lined
plenum
DD unit
90
Coil
AHRI 260
Cart. Filter
Bringing it All Together
Octave Band Center Frequency (Hz)
Unit sound power
(inlet, DI)
Unit sound power
(discharge, DD)
ASHRAE
Applications
Handbook
Room Lp
Octave Band Sound Pressure Level dB re 20 µPa
Criteria based on space type
Octave Band Center Frequency (Hz)
AHRI Sound
Standards – Chillers
Air Cooled Chiller Sound Rating
North America:
• AHRI 370 (Sound Power)
Reverberation Room Method
• Free field Over a Reflecting Plane
•
•
•
Units are usually installed outside.
Units are too big for many reverberation
rooms.
Europe/Asia:
• Eurovent
•
•
•
Reverberation Room Method
Free field over a reflecting plane
Sound Intensity
• ISO 3744
38
Water Cooled Chiller Sound Measurement and Rating
AHRI 575 – Method of Measuring Machinery Sound
Within an Equipment Space
Spatially-averaged Sound Pressure around rectangular grid
Measurements 1.5 meters (5-ft) above grade
Measurement points 1-meter (3.3-ft) away from unit, 1-meter
apart.
Measurement
Rectangle
39
Water Cooled Chiller Sound Measurement and Rating
AHRI 575 – Method of Measuring Machinery Sound
Within an Equipment Space
Provides Octave Band and A-weighted Sound Pressure
Levels, spatially averaged around the machine.
This is a method of measuring sound pressure level of
machinery installed in a mechanical equipment space. It is
was not intended to be used for sound rating of equipment.
Results depend on the environment, such as the room
reverberation, proximity to walls and other noise sources.
40
Water Cooled Chiller Sound Measurement and Rating –
Why Sound Pressure?
History:
Late 1960’s and early 1970’s
Occupational Hearing Exposure (OSHA)
Time weighted average over an eight hour shift (TWA)
115 dBA Max Allowed for 15 minutes
90 dBA TWA – Max allowed average
85 dBA TWA action level
Need sound pressure for hearing exposure
calculations.
Directivity Information.
Sound level at the control panel.
41
Water Cooled Chiller Sound Measurement and Rating –
How to get Sound Power
How do we get sound POWER from sound pressure?
Sound Pressure Level (Pa) in a free field is numerically equal to Sound
Intensity Level (W/m2).
Integrate the Sound Intensity Level over the Measurement Area to
obtain the Sound Power.
Lw = L p + 10 log S
42
AHRI Chiller Sound
Standards – The
Future
AHRI 1280 – Water Cooled Chiller Sound Power
AHRI 575
AHRI 1280
• Sound Pressure
• Sound Power
• Test Method
• Rating Standard
• Mechanical Equipment
• Multiple Methods:
• Free-Field
• Reverberation Room
• Sound Intensity
Room
44
AHRI 1280 – Water Cooled Chiller Sound Power
Why?
EU – Some manufacturers publishing sound power
data
Eliminates installation specific sound level
increases.
When?
Standard is still in development
Estimate 2014 release
45
AHRI 1280 – Water Cooled Chiller Sound Power
How will it work?
Reverberation Room – as per AHRI 370
Free-Field – Under Development
One or Two heights of measurements
Integrated to obtain sound power
Sound Intensity – Under Development
Enveloping surface
Includes scanning and point to point
Requires top measurements
Tolerances will be built into the standard
46
AHRI 1280 – Water Cooled Chiller Sound Power
• 400 ton centrifugal chiller, operating at AHRI 550/590 operating conditions,
• Fully loaded – AHRI 575 sound pressure level = 85 dBA
• 16 point AHRI 575 grid:
3 2 1 16 15
4
14
5
13
6
12
7 8 9 10 11
• AHRI
1280 sound power rating = 101 dBA.
47
AHRI 1280 – Water Cooled Chiller Sound Power
• 2000 ton centrifugal chiller, operating at AHRI 550/590 operating conditions,
• Fully loaded – AHRI 575 sound pressure level = 86 dBA
• 24 point AHRI 575 grid:
4 3 2 1 24 23 22
5
6
7
8
9
21
20
19
18
17
10 11 12 13 14 15 16
• AHRI
1280 sound power rating = 105 dBA.
48
Questions?