Terms and Definitions Used on this Site |
| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
| A |
| American Society for Testing Materials A nonprofit organization that establishes standard tests and specifications for construction materials. Such tests and specifications usually are referred to by the abbreviation ASTM followed by a numerical designation. ASTM Abbreviation for American Society for Testing Materials. Back to Top |
| B |
| BOCA Building Officials and Code Administrators. Publishes the National Building Code every three years, with yearly supplements. Most commonly referred to in the northeast states. Backloaded 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. Bevel Edge 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. BioBlock® HumiGuard® Plus ceilings are treated with BioBlock®, fungicide treatment to inhibit or retard growth of mold or mildew on painted surfaces. Border Cut Cut made on both ceiling panel and grid at the perimeter of the installation. Back to Top |
| C |
| Ceiling Attenuation Class (CAC) Rates a ceiling's efficiency as a barrier to airborne sound transmission between adjacent closed offices. Shown as a minimum value, previously expressed as CSTC (Ceiling Sound Transmission Class). A single-figure rating derived from the normalized ceiling attenuation values in accordance with classification ASTM E 413, except that the resultant rating shall be designated ceiling attenuation class. (Defined in ASTM E 1414.) An acoustical unit with a high CAC may have a low NRC. 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 Several clip designs are available to suit applications such as fire resistance, wind uplift and impact. Fire-resistance rated designs have exact requirements, including the mandatory use of hold-down clips for acoustical panels or tiles weighing less than 4.9 kg/m2 (1.0 pound per square foot). For rooms with significant air pressure differential from adjacent spaces, retention clips may be necessary to retain panels in place. Maintaining air pressure values may also require perimeter panel seals, typically a closed cell foam gasket with adhesive on one side. Cross Tee Tee that is inserted into the main runner to form different module sizes. Back to Top |
| D |
| 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 tees. Duty Classification Load carrying capability of grid components in pounds per linear foot (Light: 5 lbs, Intermediate: 12 lbs, Heavy: 16 lbs) Back to Top |
| E |
| Back to Top |
| F |
| 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. Fire Rated 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. Fissuring Method of imparting a set of ragged depressions into the face of acoustical tile or panels during manufacture for appearance and acoustical performance. 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. Flange Horizontal surface on the face of the tee, visible from below the ceiling. The part of the grid to which the color cap is applied. Most grid system flanges are either 15/16" or 9/16". Back to Top |
| G |
| Galvanized A generic term used to describe a sheet or coil of steel coated with zinc applied in an electrogalvanizing or dipping process. 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. Back to Top |
| H |
| 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. Stainless steel wire and nickel-copper alloy wire are frequently used in severe environment designs. 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. Hot Dipped Galvanized Process to coat steel to offer environmental resistance to corrosion. Cold rolled steel is submerged (dipped) into a molten zinc bath. A heavy coating of zinc is applied to the steel substrate. Zinc coating thickness varies and is designated by a G series, such as G-60 or G-90. Back to Top |
| I |
| ICBO Organization based in Sacramento, California, that sets seismic standards primarily for the western United States. Publishes the Uniform Building Code. 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. Back to Top |
| J |
| Back to Top |
| K |
| Back to Top |
| L |
| Living Room Ceilings Armstrong’s ceiling tiles, planks and panels can help define and add flair to your personal sense of style. Create a space that is uniquely you. View living room ceilings from Armstrong. Back to Top |
| M |
| 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. ML Cross tee end detail that is a hook insertion contrasted with the XL that is stab insertion. The ML end detail is quick and easy to install however, it does not meet most seismic requirements greater than Zone 2. Back to Top |
| N |
| 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. Back to Top |
| O |
| 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. Back to Top |
| P |
| Plenum In suspended ceiling construction, the space between the suspended ceiling and the main structure above. Back to Top |
| Q |
| Back to Top |
| R |
| R Factor A number measuring a materials resistance to heat flow. R stands for resistance, the inverse of conductivity. Values reported in this catalog were determined by the ASTM C 518 test method. Values are reported at a mean temperature of 75 degrees F (24 degrees C), and as the inverse of BTU/hr sf degrees F (imperial units), and Watts/m2 degrees C (metric units). Rotary Stitching Process by which two vertical layers of steel are stitched or bonded together to form a more homogeneous component exhibiting increased column strength, torsional strength, and overall handleability. Armstrong is the only grid manufacturer to employ this technology. Back to Top |
| S |
| 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. Scrubbable For applications where cleanliness is a priority, acoustical units may require cleaning beyond normal maintenance procedures. Acoustical panels with special facing materials such as Mylar or vinyl film offer superior scrubbability without compromising panel finish integrity. Metal ceilings may also be used for scrubbable applications. The accepted test procedure is the Gardner Scrubbability Test ASTM D 2486. Stab End Detail Designed to be inserted with a forward motion. Stitching Dimples impressed in grid members to knit the webs together. Suspension System 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. Back to Top |
| T |
| 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. Temperature and Relative Humidity (RH) Resistance Temperature and humidity affect acoustical panel and tile dimensional and planar stability. Standard acoustical panels and tiles are designed for installation within the normal occupancy condition range of 15 to 29 degrees C (60 to 85 degrees F) and maximum 70 percent RH. When the in-service use temperature and RH are expected to exceed these ranges, consider the use of acoustical units specifically designed for these applications, like HumiGuardTM ceilings. Anticipate lower overlaid thermal/ acoustic insulation (commonly referred to as backloading) limits for these designs. Tile Acoustical ceiling board, usually 12" x 12", which is stapled, cemented, or suspended by a concealed grid system. Edges are often kerfed and cut back. Back to Top |
| U |
| 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., indicating that the labeled product: (a) has a rating based on the performance tests of such products (b) is from a production lot found by examination to be made from materials and by processes essentially identical to those of representative products which have been subjected to appropriate fire, electrical hazard, or other tests for safety and (c) is subject to the reexamination service of UL. ULI Underwriters Laboratories, Inc. Back to Top |
| V |
| Back to Top |
| W |
| Back to Top |
| X |
| Back to Top |
| Y |
| Back to Top |
| Z |
| Back to Top |