Acoustical Ceilings - Glossary of Terms:
The ceiling in most cases is the most visible, eye catching part of the building. The choices made, and the design for installation mean too much.
Differing level lines around the room, out of the ordinary angles, varying colors and lighting all add to the scheme of the property.
Back-loaded Insulation : Thermal/acoustical insulation placed above the ceiling suspension system, laid across the horizontal grid members above the
acoustical panels or tile. Also referred to as backloading.
An acoustical tile is considered bevel edge material when the face of the tile
turns up at the edge at approximately 45 degrees for 1/8" to 1/4" around the perimeter of the tile.
Border Cut: Cut made on both ceiling panel and grid
at the perimeter of the installation.
Ceiling Suspension System: A system of metal members, designed to support a suspended ceiling, typically
an acoustical ceiling. Also may be designed to accommodate lighting fixtures or air diffusers.
Clips : Special designs to suit applications: fire resistance, wind
uplift, impact, etc. Fire-resistance rated designs have exact requirements.
Cross Tee: Tee that is inserted into the main runner to form
different module sizes.
Deflection: Bending or deviation from a straight line or course. Used
here as the standard by which allowable load for suspension system
components is measured.
Double Web: Indicates two layers of
material in the construction of the vertical web of main runners and cross
Duty Classification: Load carrying capability of grid components in
pounds per linear foot (Light: 5 lbs, Intermediate: 12 lbs, Heavy: 16 lbs).
Fiberglass Panels: Processed from a molten state into fibrous glass
strands, then formed into board stock. The manufacturing process requires a
separate dimensionally stable facing material laminated to the fiberglass
core to provide texture and pattern. Fiberglass, vinyl and polyester facings
are typically used.
Fire Guard Grid: Fire resistance rated grid.
Refers to the UL fire resistance rating of an assembly.
Fire Resistance: The property of acting as a barrier to fire.
Acoustical ceiling systems form a membrane to contain fire within a room.
Fire-rated assemblies (including ceiling panels, suspension system, light
fixtures and diffusers, and structural components) are given ratings of one,
two, three or four hours as tested per ASTM E 119.
Flame Spread Rating:
A single number measurement of the flame spread across the surface of a
material. Defined by ASTM E 84 commonly known as the 25-foot tunnel test, the
number is obtained by comparing with red oak flooring.
Gauge: Thickness of the steel used to make a grid member. May be
expressed by a number designation (26 GA.) or in thousandths of an inch (0.013).
Grid: Structural system of main beams, cross tees, and associated
hardware, which hangs from the deck above and supports lay-in, concealed or
surface attached ceiling panels.
Hanger Wires: Wire employed to suspend the acoustical ceiling from the
existing structure. The standard material is 2.05 mm (16 gauge) galvanized, soft
annealed steel wire, conforming to ASTM A 641M or A 641. Heavier gauge wire is
available for higher load carrying installations, or situations where hanger
wire spacing exceeds 1200 mm (4 feet) on center. Seismic designs or exterior
installations subject to wind uplift may require supplemental bracing or
substantial hanger devices such as metal straps, rods, or structural angles.
Hold Down Clip: Mechanical fastener that snaps over the bulb of a grid
system to hold ceiling panels in place.
Hook Tee: Cross tee with an end tab that hooks through the rout hole
and rests on the vertical web of the main runner.
Intermediate-Duty Systems: These are used primarily for ordinary
commercial structures where some ceiling loads, due to light fixtures and air
diffusers, are anticipated.
Main Beam, Main Runner, Main Tee: Primary or main beams of the type of
ceiling suspension system in which the structural members are mechanically
locked together. Provide direct support for cross runners and may support
lighting fixtures and air diffusers, as well as the acoustical tile. Supported
by hanger wires attached directly to the existing structure or installed
perpendicular to carrying channels and supported by specially designed sheet
metal or wire clips attached to the carrying channels. Typically a 12' piece
located 4' on center. Also referred to as H runners and Z bars
Mineral Wool: A man-made wool-like material of fine inorganic fibers
made from slag, used as loose fill or formed into blanket, batt, block, board,
or slab shapes for thermal and acoustical insulation.
Noise Reduction Coefficient (NRC): Average sound absorption
coefficient measured at four frequencies: 250, 500, 1,000 and 2,000 Hz expressed
to the nearest integral multiple of 0.05. Rates the ability of a ceiling or wall
panel or other construction to absorb sound. NRC is the fraction of sound
energy, averaged over all angles of direction and from low to high sound
frequencies, that is absorbed and not reflected.
Override: Offset on the end of some cross tees that rests on top of
the supporting members flange. Increases stability and moves cut edge of tee out
of the visible plane of the ceiling.
Plenum:In suspended ceiling construction, the space between the
suspended ceiling and the main structure above.
Scoring: Process of cutting grooves into the face of acoustical panels
creating a different geometric visual with decorative and some acoustical
benefit. Scoring often mimics the suspension grid, camouflaging it and making 2'
x 2' and 2' x 4' panels look like 12" x 12" tile.
Suspension: A metal grid suspended from hanger rods or wires,
consisting of main beams and cross tees, clips, splines and other hardware which
supports lay-in acoustical panels or tiles. The completed ceiling forms a
barrier to sound, heat, and fire. It also absorbs in-room sound and hides
ductwork and wiring in the plenum.
Tegular: A functional edge detail. Tegular suspended ceiling panels
have a rabbeted/reveal edge design that allows them to extend below the
supporting grid, making the grid less conspicuous.
UBC 25-2: Uniform Building Code (seismic standard).
UL Label: An identification affixed to a building material or
component, with the authorization of Underwriters Laboratories, Inc.
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We make architectural parts.
The ceiling in most cases is the most visible, eye catching part of the building. The choices made, and the design for installation mean
too much. Differing level lines around the room, out of the ordinary angles, varying colors and lighting all add to the scheme of the property.
We make architectural installations.
Wholesale and fabricated parts for office fit-outs, acoustical, suspended, commercial property ceilings and architectural access panels.