Temperature – Humidity
Particular emphasis must be given to the status of all interior
wet work at job sites. Acoustical ceiling products are
designed to be interior finish materials suitable for installation
within a normal occupancy temperature range of 60°F to 85°F (16 - 29°C) with
relative humidity no higher than 70% (certain products can
withstand higher temperature of 104°F (40°C) and
humidity conditions of 90, 95 or 100% relative humidity.)
Prior to installation, all plastering, concrete, or other
wet work must be completed and dry. All windows and doors
must be properly installed. Furthermore, heating, ventilating,
and air conditioning systems should be installed and in
operation as necessary to assure proper temperature and
humidity conditions before, during, and after installation
of the acoustical material.
If using the ceiling plenum as a return air duct, caution
should be exercised such that any introduction of outside air
does not cause the plenum to exceed the recommended humidity
levels. These ceiling materials should be stored at temperature
and humidity conditions not exceeding maximums shown in previous
section, and should not come in direct contact with water and
moisture. Materials exposed to direct moisture or water must
not be installed. Conditioning of material near actual design
environment is the ideal situation. Ceiling product cartons
must never be used as a substitute for scaffolding or ladders.
Lighting
In considering job conditions and standards which affect the
appearance of the completed ceiling installation, it is recommended
that the lighting selected be the type that will enhance
the ceiling rather than create an adverse or unsatisfactory
appearance. Factors influencing ceiling appearance are: intensity
of light, height of ceiling, direction of light including
outside light through windows, and mounting of fixtures.
The most critical of these is the direction of the light
source in relation to the ceiling plane. Low angle light,
whether from a fixture or from the building exterior, accentuates
normal ceiling plane irregularities adversely affecting the
final appearance of the installation.
An unfavorable appearance condition can result early in a
ceiling installation before occupancy lighting is in place
and in use. Temporary construction lighting seldom provides
a satisfactory evaluation of the ultimate finished ceiling
appearance. Architects should specify that occupancy lighting
is in use before any critical inspection of the ceiling is
made. If the normal occupancy use is under artificial light
approval/acceptance inspections should be made only under these
conditions.
Concealed Tile for Glue-Up Installation
CertainTeed tiles recommended for adhesive application are: BET-162,
CM-462 and PCM-462. Apply to dry concrete, dry concrete block,
gypsum board, dry plastered areas, or well-bonded paints.
Do NOT use over wood or metal ceilings, uninsulated roof
decks, wallpaper or loose peeling paint. Use adhesive that
meets ASTM D1779, Specification for Adhesive for Acoustical
Materials.
Thermal Insulation Above Suspended Ceilings
The practice of installing insulation on the back of suspended
ceilings (backloading) is not advised. The proper location
for insulation materials is in the roof structure, because
this places the dew point outside of the plenum thereby avoiding
condensation damage to the grid, tile, light fixtures, etc.
If other job considerations require insulation to be installed
on the back of the ceiling, the following points must be
carefully considered. CertainTeed will not be responsible for damage
or failure of the acoustical material, grid, light fixture,
structure, etc. due to condensation, or excessive loading
on back of ceiling.
- If the ceiling must be insulated, a vapor retarder faced
or non-faced roll insulation may be used. If the roll insulation
is faced, install the vapor retarder facing down toward
the back of the ceiling panel. Non-faced roll insulation
is required for backloading fiberglass ceiling products.
Batt insulation must be non-faced and used for 24" x 24" panels
only.
- Rolls are preferable to batts. Rolls span multiple cross tees with only
occasional contact with back of acoustical material.
- Insulation must weigh not more than 0.26 Ib./sq. ft. (approximately 6" (R19)
of glass fiber insulation) for mineral, fiberglass (24" x 24" and
24" x 48" panels only) and composite ceiling products. Commercial
and Commercial Mat 5/8" fiberglass products may not be backloaded
with insulation. Acoustical materials are not structural and excessive
weight can cause ceiling to sag or even fall.
- Insulation must weigh not more than 0.52 lb./sq. ft. (approximately 13" (R38)
of glass fiber insulation) for gypsum ceiling products.
Insulation is to be applied perpendicular to the suspension cross tees so
that the grid carries main load of insulation.
- Insulation must not be placed on back of Protectone® fire resistance
rated ceilings.
- A professional engineer must be consulted for design of plenum venting system
to preclude condensation in the plenum.
Installation of Speakers and Spotlights
CertainTeed ceiling panels shall not be used to support the weight
of speakers, grills, spotlights and the like, either wholly
or in part. Components such as these must be supported independently
of the ceiling panels themselves.
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