f.
Nominal Size: 600 by [600] [1200] mm 24 by [24] [48] inches.
g.
Edge Detail:
Square.
h.
Joint Detail:
Trimmed and butted.
2.1.7
Unit Acoustical Absorbers
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NOTE: Unit acoustical absorbers should be used in
high noise areas such as bowling alleys, industrial
areas or in other locations when recommended by an
acoustical consultant. Quantity and spacing should
be shown on the drawings.
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Absorbers shall be individually mounted sound absorbing plaques composed of
glass fibers or non-asbestos mineral fibers and having a NRC range of not
less than 0.60 - 0.70 when tested in accordance with ASTM C 423 and
reported as a 4 frequency average.
2.2
SUSPENSION SYSTEM
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NOTE: If more than one type of acoustical unit is
required, a separate paragraph for that type unit
will be used. Each unit type will be designated
with a letter or number symbol, such as A, B, etc.
Use the same letters or numbers to key unit types to
locations listed or shown on the drawings and in
Section 09915, COLOR SCHEDULE.
Each different type of suspension system must be
shown on the drawings.
Generally, lay-in panels supported by exposed grid
suspension system provide most economical
installation and allow greatest access to space
above ceiling. Where lay-in panels are subject to
displacement by building occupants or where ceiling
must be directly attached to underside of structural
system, concealed framing system may be more
appropriate. In lobbies, auditoriums, chapels or
clubs where a monolithic appearance may be desired,
greater expense of concealed suspension system may
be justified. Downward access concealed systems
should not be specified in areas of high seismic
activity.
An intermediate-duty suspension system should be
specified when the minimum load-carrying capacity of
the main runner is 175 N per m (12 pounds per linear
foot) on a simple span of 1200 mm (4 feet) without
the mid-span deflection exceeding 1/360th of the
span. Intermediate-duty systems are used primarily
for ordinary commercial structures where some
ceiling loads, due to light fixtures and air
diffusers are anticipated.
SECTION 09510
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