MIL-HDBK-1191
23.3
ROOM ACOUSTICS.
23.3.1
General. The character and quality of acoustics within is a space
is a function of the finish materials in the room (whether they are sound
absorbing or sound reflecting) and the volume and shape of the room. Adequate
areas of sound absorbing materials can reduce noise within the space, make the
room more comfortable because reflections are not coming from all directions,
and greatly improve speech intelligibility.
23.3.3
Design Guidelines.
23.3.3.1
Ceilings. Most general purpose spaces in military health care
facilities can be made comfortable for noise control and room acoustics by
judicious application of suspended standard acoustic tile ceilings. In
potentially loud spaces, such as a cafeteria or industrial work area, the
absorbing material should be chosen to have a particularly high NRC value,
perhaps .75 or greater. In spaces with high ceilings, the additional volume
increases reverberation in the space, and so such rooms should have additional
sound absorbing wall treatments.
23.3.3.2
Other spaces. Special environments for presentations,
conferences, lectures or loud labs may require specialized room shaping
analysis and special sound absorbing approaches, including additional
absorbing materials on walls.
23.4
MECHANICAL AND ELECTRICAL SYSTEMS NOISE AND VIBRATION CONTROL.
23.4.1
General.
23.4.1.1
Introduction. Mechanical systems create the most pervasive noise
sources in buildings. Figure 23.5 shows the range of noise levels produced by
typical building equipment. The noise problem is exacerbated in modern
buildings because the buildings are often lightweight structures which easily
transmit sound and vibration. Care should be taken in the location,
selection, and installation of mechanical equipment and in the design of the
enclosing constructions. When economically practicable, major mechanical
equipment such as water chillers, boilers, pumps and compressors should be
located in central plants totally separated from the health facility building.
Mechanical equipment that remains within the building, such as air handling
units, should be located in spaces that are segregated from acoustically
sensitive areas, both vertically and horizontally, by the layout of non-
critical buffer spaces (such as corridors) to avoid the need for special sound
isolating constructions between equipment rooms and acoustically sensitive
spaces.
23.4.1.2
Mechanical Systems Design. Careful consideration must be made to
the selection, location, and installation of mechanical system components to
insure compatibility with the building occupants and functional requirements.
The misapplication of mechanical system components and their relationship to
adjacent spaces can result in unwanted noise which is often annoying and could
impede the facility function. The sections that follow address specific parts
of the design approach for mechanical system noise and vibration control.
These parts are: duct-borne fan noise; air-generated noise; cross-talk between
spaces; noise control within mechanical equipment rooms; vibration isolation;
and plumbing noise. These sections present general guidelines, and do not
replace detailed engineering analysis.
Refer to additional requirements for
mechanical system noise control in Section 8 of this document.
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