Sound - Trane GECA Installation Operation & Maintenance

The Challenge of Low Sound
The GECA product line was developed
to be the industry leader in noise
performance. To achieve that goal, state
of the art acoustic design and test
technologies were used to identify and
treat the dominant noise and vibration
transmission paths in each unit. As a
result, numerous noise control features
have been incorporated in the GECA
units, including: See Figure PD-1 for
compressor noise control for model
GEHA.
•
Two stage compressor vibration
isolation systems with 12-gauge
intermediate mounting plates
•
Lined compressor enclosure
•
Heavy-gauge base assembly
•
Maximum sized return-air opening and
filter sizing
•
Water-to-refrigerant heat exchanger
vibration isolation
To ensure consistent performance, an
extensive series of tests were conducted
on each cabinet size:
•
Mock-up (NC) sound pressure testing
(a noise evaluation in typical REAL
WORLD installation).
•
Sound power testing per ARI's new
standard 350 for non-ducted air
handling equipment (a noise
evaluation to quantify the strength of
various sound components for
application in building system design).
These include:
GECA: Inlet + Casing Discharge
For unit specific octave band sound
power data, please refer to the TOPPS
selection program.
WSHP-PRC004-EN
Performance
Data
Figure PD-1 – Elevation View of Noise Control
What is Sound Pressure?
Sound pressure is a pressure
disturbance in the atmosphere whose
intensity is influenced not only by the
strength of the source, but also by the
surroundings and the distance from the
source to the receiver. Sound pressure is
what our ears hear, and what sound
meters measure. The level of sound
pressure, or the loudness of a given
noise source, depends on three factors:
1. The strength of the source
2. The environment in which the source
is located
3. The listener's distance from the source

Sound

As an example, of the effect of
environment, consider the sound
produced by a drum. Clearly, the drum is
perceived to be louder in a bathroom
with hard tile walls than it is in the
middle of a football field. Also, the
farther one moves away from the drum,
the quieter it sounds. In each case, the
vibration of the drum (the strength of the
source) is the same; the perceived
differences in noise level are due to the
environment.
Because of the extremely wide range of
sound pressure perceivable by a person-
typically five or six order of magnitude –
it is convenient to express sound
pressure on a logarithmic scale. As a
result, adding two equal sound sources
together will result in an overall increase
of 3 dB. However, 3 dB is barely a
perceptible increase in sound. It takes an
increase of 10 dB to be perceived as
twice as loud.
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