adjacent areas. The designer should consider sound
within the equipment room, adjacent areas and
building exterior. Acceptable sound levels will
vary depending on the function of the space. As a
minimum the design should comply with the following
OSHA safety requirements; however, more stringent
sound restrictions may be required to met the
functional requirements of the occupied spaces.
Frequency Band
Maximum Acceptable
(Hz)
Sound Level
(Decibels)
Industrial Residential
20-75
87
81
75-150
77
71
150-300
70
64
300-600
64
58
600-1,200
61
55
1,200-2,400
60
54
2,400-4,800
60
54
4,800-10 kHz
62
56
Typically, the diesel generator manufacturer can
provide information concerning the noise generated
by the diesel generator in a free field environment.
The manufacturer does not have control over any
other building parameters or additional mechanical
equipment noise. Therefore the designer should
indicate the required sound limits for each of the
indicated octave bands for the sound pressure level
of the diesel generator set operating at 100% load
in a free field. The designer should develop these
numbers based on the desired sound levels that
should exist at various locations after the
generator is installed. This information should be
based on the values used in the acoustical analysis
and verified by coordination with equipment
manufacturers during design. In some cases, a sound
attenuated enclosure may be needed to achieve the
desired result.
The designer should also indicate the desired sound
pressure levels that will be measured in the field.
The pressure levels should be based on the
acoustical analysis and should consider the
specified operating conditions of the diesel
generator operating in a free field, other
mechanical equipment, the building's sound
absorption characteristics, OSHA requirements, and
the building's functional requirements. The
SECTION 16263A
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