Acoustical Performance Terms

Fire Performance Terms

Light Reflectance Terms

Suspension System Terms

General Terms

Application Standards







Acoustical Performance Terms

Absorption - In acoustics, the energy of sound waves being taken in (entering) the surface of any material rather than being bounced off or reflected. Materials are rated in terms of their ability to absorb sounds.

Acoustical Materials - Materials which have high absorption coefficients of at least 0.50.

Amplifier - An electronic device used in sound system applications to convert a low level signal such as from a microphone or CD player into a high power signal (rated in watts) capable of powering a loudspeaker to a high sound level.

Amplitude - The maximum variation of any wave from its mean value. Increasing a sound wave's amplitude increases its loudness.

Analog - In sound system applications, an analog electrical signal represents the measured sound level in its exact continuous form. Likewise, an analog device is an electronic device that processes analog signals in their continuous form.

Articulation Class (AC) - A measure for rating the speech privacy performance of a ceiling in an open plan environment between two adjacent areas divided by partial-height screens.

Articulation Index (AI) - Measure of speech intelligibility with a numerical value ranging from 0 to 1. An AI of 0.1 is indicative of low speech intelligibility; an AI of 1.0 means speech is perfectly intelligible. The Privacy Index is derived from the AI calculation.

Attenuation - In acoustics, the reduction of sound energy as it passes through a material. Materials are rated for their ability to prevent sounds from traveling through them.

Ceiling Attenuation Class (CAC) - Rates a ceiling's performance as a barrier to airborne sound transmission between adjacent closed offices. An acoustical unit with a high CAC may have a low NRC.

dBA (A-weighted decibel) - A single-number sound measurement in decibels that is weighted to approximate the human hearing response.

Decibel (dB) - A unit to express differences in sound level. The dB level is a logarithmic quantity; the range of levels normally experienced is from 0 to 120 dB.

Directivity Index - A measure of the angular direction of the sound radiation from the loudspeaker, presented as a dB level either higher or lower than that which would be radiated by a spherical sound source.

Dispersion - Refers to the way in which sound spreads outward from a loudspeaker, in a sound systems application. Dependent on the directivity index and the distance away from the speaker.

Exciter - The electro-mechanical device which converts an electrical signal from the amplifier into a mechanical vibration of the loudspeaker radiator, causing a sound wave to be produced with the same characteristics as the electrical signal. Also called a transducer.

Flanking Sound Path - A sound transmission path, such as a structural path, that bypasses a transmission barrier.

Frequency - Cycles per unit of time. Usually expressed in Hertz (Hz). The frequencies of audible speech lie in the range of 400-2000 Hz. Hertz (Hz) - One cycle per second.

Masking Sound - Electronically generated background sound of a specified level and frequency content that is introduced into occupied environments to provide masking of intrusive noises and to enhance speech privacy.

Noise Isolation Class (NIC) - A single-number rating of the sound-isolating performance of a building element. Used when flanking sound paths cannot be isolated to establish the Field Sound Transmission Class (FSTC).

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.

Octave - A frequency interval wherein the higher frequency is twice the lower frequency.

Octave Band - The audio frequency range is generally separated into octave bands as a matter of convenience, wherein each specific band is represented by its center frequency, e.g. 63 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz and 16 kHz, which cover most of the audible frequency range.

Ohm - Unit of electrical resistance; e.g. most loudspeakers are typically 8 ohms.

Open Plan Office - An office in which acoustical screens, most commonly 60-inches high, are used in place of ceiling-high partitions. Ceilings used in open plan offices must have different acoustical properties than those used in closed offices.

Pin Perforation - A method of improving the acoustical performance of a ceiling tile or panel by punching holes in its surface during manufacture.

Pink Noise - Electronically generated sound that has equal energy in each octave band; typically used as the basis for the post-filtered signal used as masking sound.

Plenum Barrier - Vertical surface framed from the structure above to the finished ceiling and sealed to prevent the passage of air or sound.

Polar Pattern - The graphical representation of the coverage of a loudspeaker at various frequencies.

Privacy Index (PI) - A measure of speech privacy, or lack of speech intelligibility, where the PI is calculated from the Articulation Index (AI) according to the following: PI = (1 - AI) x 100%.

Processor - A general term used in sound system applications to describe an electronic device that may have the following functions: signal generation, signal conditioning, equalization and mixing.

Reverberation - Persistence of reflected sound in a room after its source has stopped emitting sound.

Reverberation Time - Time required for a sound to decay by 60 decibels.

Sound Attenuation - The reduction in the sound pressure level of sound which is transmitted from one point to another.

Sound Leaks - Cracks under doors, openings in a wall, pipe or wiring holes, etc., which allow sound to escape through a structure from one room to another.

Sound Masking - The process by which masking sound is implemented to cover unwanted or intrusive sound (i.e. speech, equipment noise, etc.) and to enhance speech privacy.

Sound Spectrum - A representation of a sound wave (time varying pressure wave) showing the frequency content and amplitude of the sound over the audio frequency range.

Sound Transmission Class (STC) - A single-number rating of a structure's efficiency as a barrier to airborne sound at 16 speech frequencies from 125 to 4000 Hz. (See ASTM procedure E 1414 for rating method.) Rates the ability of a wall or other construction to block sound: STC is a decibel measure of the difference between the sound energy striking the panel or construction on one side and the sound energy transmitted from the other side. This includes sound from all angles of direction, and from low and high sound frequencies.

Sound Transmission Loss - The amount of sound lost as the sound travels through a material. Acoustical ceiling assemblies are rated in terms of Sound Transmission Classifications. An STC value of 20-25 would indicate that even low speech would be audible in an adjoining room. An STC value of 50-60, on the other hand, would indicate that loud sound would be heard only faintly or not at all.

Speech Privacy - Refers to the lack of speech intelligibility from adjacent talkers. Several levels of speech privacy are defined in the ASTM standards, from Confidential privacy (meaning speech sounds can be heard but not understood), to Normal privacy (meaning that speech can be occasionally heard and understood but is generally non-intrusive), to Poor privacy (wherein all adjacent speech can be heard and understood). These levels can be related to ranges of PI representing each level of speech privacy.

Speech Range Absorption - The average of the absorption coefficients at 500, 1,000, 2,000 and 4,000 Hz.

Transformer Tap - Refers to the power setting available on a step-down transformer (e.g. 1 watt, 2 watt, 4 watt, etc.) used in high voltage distributed sound systems (e.g. 70V, 50V and 25V amplifier systems).

Volt - Unit of potential difference or electromotive force. One volt is the potential difference needed to produce one ampere of current through a resistance of one ohm. Voltage is the driving force throughout a sound system from the microphone input to the speaker terminals.

Watt - Unit of electrical power required to do work at the rate of one joule per second. One watt of power is expended when one ampere of direct current flows through a resistance of one ohm. The power capability of amplifiers and loudspeakers is given in watts, which relate to both the voltage driving the system and the current handling capabilities of the devices.

White Noise - Electronically generated sound that has equal energy at each frequency so that the octave band level increases by 3 dB for each increase in octave; white noise is typically perceived to sound "hissy" compared to pink noise.

Fire Performance Terms

Expansion Joint - Area of a fire-rated component designed and punched to provide thermal expansion relief for that component. Due to expansion of steel when heated, this expansion control is necessary to keep the fire membrane intact.

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.

Flame Spread Index - A numerical designation, applied to a building material, which is a comparative measure of the ability of the material to resist flaming combustion over its surface; the rate of flame travel, as measured under the applicable ASTM E 84 test, in which a selected species of untreated lumber has a designated value of 100, and noncombustible inorganic reinforced cement board has a value of 0.

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. The following classes are defined under ASTM E 1264:

0-25 0-50 A
26-75 - B
76-200 - C

NFPA - Abbr. for the "National Fire Protection Association."

Smoke Developed - The ratio of the smoke emitted by a burning material to the smoke emitted by the red oak standard material.

Smoke Developed Rating - A relative numerical classification of a building material as determined by an ASTM E 84 test of its surface burning characteristics.

Surface Burning Characteristics - Published flame spread and smoke developed indices for acoustical units measure surface burning behavior (characteristics) during exposure to fire. Test methods provide data in comparison with noncombustible cement board and untreated red oak lumber when exposed to fire under similar conditions. Nationally accepted equivalent test methods are ASTM E 84, NFPA 255 and UL 723.

Light Reflectance Terms

Illuminance Levels - Illuminance is the quantity of light falling onto a surface. It is measured in footcandles or lux (metric measure). One footcandle is approximately 10 lux.

Light Loss Factor (LLF) - Used to calculate illuminance loss after a given period of time and under given conditions, like dirt accumulation and heat buildup in the fixture.

Light Reflectance (LR) - Light reflectance of a surface is its property of reflecting light. The measure of light reflectance is that fraction of the specified incident light reflected by the surface. (Defined in ASTM E 1477).

Nonspecular Surface - Describes a surface which is diffuse, meaning it reflects light in equal amounts in all directions. This is important because a nonspecular ceiling's brightness will be the same regardless of viewing position. Typically, nonspecular (diffuse) surfaces are less glossy and produce less offensive glare.

Suspension System Terms

Access Hook - Used in concealed tee system to support the last row of tile to be installed in a 42 x 42 module that also allows access to the plenum above. Also called Saddle Spline.

Breather Spline - Spline used to link tiles in a concealed tee installation and to prevent air infiltration.

Bulb - The upper ridge of the main runner or cross tee with a rectangular, triangular or round configuration. Adds structural load strength to the component.

Cap - The rolled covering on the flange of a T-Bar. T-Bars come with an aluminum or steel cap and in many colors.

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 holddown 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.

Concealed Mounting System - Tile suspension system using T-Bars and splines which fit into kerfs cut into tile edges. Unlike exposed-grid systems, concealed mounting systems are not visible from below the ceiling. Inverted tee, "H and T," or "Z" profile grids are common for these applications with provisions for full plenum access usually incorporated into the grid design.

Cross Runner - The secondary or cross beams of a mechanical ceiling suspension system, usually supporting only the acoustical tile. In some suspension systems, however, the cross runners also provide support for lighting fixtures, air diffusers and other cross runners. 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 tees.

Downward Access System - Direct access is achieved by removing individual units with an access clip or key. Multiple panels designed as end- or side-pivoting units can also be used. The number of permissible access openings are fewer with an end pivot design. Downward access may be desirable if tight plenum clearance is a problem. In fire-rated designs, the amount of each access area and pan size is governed by testing criteria.

Duty Classification - Load carrying capability of grid components in pounds per lineal foot (Light: 5 lbs, Intermediate: 12 lbs, Heavy: 16 lbs).

Electrogalvanized - A plating process that deposits a coating of zinc on a cold rolled steel substrate. Thickness or weight of coating can be varied and is typically categorized as heavy-electro through standard-electro or "flash" electrogalvanized. Process providing rust resistance for metal.

Environmental Systems - Grid systems that are made of base materials that withstand a variety of moist and corrosive conditions.

Exposed Grid System - Structural suspension system for lay-in ceiling panels. Factory-painted supporting members are exposed to view. Exposed tee surfaces may be continuous or have an integral reveal. Reveals are typically formed as channel profiles extending down from the tee leg. Bolt-slot type reveal designs can accommodate partition attachment. The choice may be restricted by appropriate tee width for panel selected and limitations on available panel edge details for the chosen grid profile.

Fixture Weight - Individual weight of mechanical services supported by ceiling grid members.

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 15/163 or 9/163.

Galvanized - A generic term used to describe a sheet or coil of steel coated with zinc applied in an electrogalvanizing or dipping process.

Gasketed Grid - Ceiling suspension system that has foam rubber gasketing attached to the top side of the flanges. Used in clean room ceilings to seal the panels to the grid.

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 (12 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.

Heavy-Duty Systems - Primarily used for commercial structures in which the quantities and weights of ceiling fixtures (lights, air diffusers, etc.) are greater than those for an ordinary commercial structure.

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.

Integral Splice - Connects the mains or tees together and is formed from the base metal of the components.

Intermediate-Duty Systems - These are used primarily for ordinary commercial structures where some ceiling loads, due to light fixtures and air diffusers, are anticipated.

L/360, Span/360 - The distance between support points of a suspension system member divided by 360. The result of this mathematical equation is the maximum amount of deflection that is allowed under ASTM C 636.

Light-Duty Systems - Used primarily for residential and light commercial structures where ceiling loads other than acoustical tile or lay-in panels are not anticipated.

Load - Amount of force (weight) that is applied to a lineal foot of any load bearing member of a ceiling system.

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 48" on center. Also referred to as "H" runners and "Z" bars.

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.

Override - Offset on the end of some cross tees that rests on top of the supporting member's flange. Increases stability and moves cut edge of tee out of the visible plane of the ceiling.

PeakForm - An improvement in the main beam bulb design from a rectangular shape to one that culminates to a point, or peak. Unique profile increases strength and stability of grid during installation.

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.

Semi-Concealed Installation System - Installation system in which tile kerfs are shallow enough to leave gaps between the tiles in one direction, exposing the grid on two sides. Usually an inverted grid. Two opposing panel edges are fabricated for a concealed grid profile.

Seismic Compression/Tension - The capability of a grid member connection to carry a mean ultimate test load in compression/tension.

Shadow Molding - A W-shaped molding that will produce a reveal or space between the ceiling and the wall when fastened to the wall.

Slotted Systems - Either bolt-slot or screw-slot systems, both of which offer a dimensional look to an otherwise flush ceiling using 9/163 exposed components. Typically feature a 1/83 or 1/43 groove that runs down the center of the components.

Spline - A strip of metal or fiber inserted in the kerfs of adjacent acoustical tile to form a concealed mechanical joint seal.

Stab End Detail - Designed to be inserted with a forward motion.

Stabilizer Bar - U-shaped channel, either 242 long or 482 long, designed to maintain cross tee spacing at the perimeter. Used in seismic installations to help prevent cross tees and panels from falling from the suspension system during an earthquake.

Stiffening Brace - Used to prevent uplift of grid caused by wind pressure in exterior applications.

Stitching - Dimples impressed in grid members to knit the webs together. (See Rotary Stitching)

Superlock - Main beam end detail that is a stacked-on "stab" insertion similar to the XL end detail on cross tees. Stacked-on main beam clip provides a strong, secure connection that is easy to remove and relocate.

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.

T-Bar - Any metal member of "T" cross section used in ceiling suspension systems.

UL 580 - Wind uplift test (Class 15 - 15 lbs/sf; Class 90 - 90 lbs/sf).

Wind Uplift - Resistance to wind uplift forces may be necessary for exterior ceiling and soffit designs. A substantial hanger system design, incorporating rods or straps, plus acoustical unit retention clips, is commonly required. Verify code requirements for wind uplift force resistance and manufacturer's recommendations for ceiling installations based on these values.

Z-Bar Concealed - Metal strips which are attached to a 1-1/23 carrying channel, one foot on center and at right angles to the channel. Also called Zee runners.

Z-Bar Exposed - A Z-Bar clipped to 1-1/23 channels to support acoustical tile on the exposed bottom painted flange of the "Z."

General Terms

Access Tile - A removable acoustical tile with special kerfing details.

American National Standards Institute (ANSI) - An independent organization of trade associations, technical societies, professional groups and consumer organizations, formerly known as the United States of America Standards Institute (USASI or ASI) and previously as the American Standards Association (ASA).

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 - Abbr. for "American Society for Testing Materials."

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 for 1/83 to 1/43 around the perimeter of the tile.

BioBlock - Added feature of HumiGuard Plus ceilings; a fungicide treatment to inhibit or retard growth of mold or mildew on product's painted surfaces.

Border Cut - Cut made on both ceiling panel and grid at the perimeter of the installation.

Clean Room - An assembly room for precision products whose quality would be affected by dust, lint or airborne pathogens; usually has smooth room surfaces to prevent dust collection; air precipitators or filters keep dust, lint, etc., to a specified minimum level.

Demountable Partition, Relocatable Partition - A nonload-bearing partition of dry construction assembled from prefabricated components which can be installed, removed, and then reinstalled at a different location; may be full height, from floor to ceiling, or partial height.

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.

Fissuring - Method of imparting a set of ragged depressions into the face of acoustical tile or panels during manufacture for appearance and acoustical performance.

Footcandle - The average illumination resulting when one lumen of light falls on one square foot of surface. Total lumens on surface divided by area of surface equals footcandles.

ICBO - Organization based in Sacramento, California, that sets seismic standards primarily for the western United States. Publishes the Uniform Building Code.

Impact Resistance - In certain applications, such as gymnasiums, locker rooms, classrooms, corridors and institutional settings, acoustical ceiling assemblies may be subjected to impact from objects. Impact resistant assemblies with acoustical lay-in panels typically require retention clips to keep panels in place upon direct impact.

Kerf - Groove in the edge of ceiling tile which accommodates and hides a suspension member.

K2C2 - Kerfed two sides, cut two sides.

K4C4 - Kerfed and cut on all four sides.

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.

Panel - Any lay-in acoustical board that is designed for use with an exposed mounting system.

Partition - A dividing wall within a building; may be load-bearing or nonload-bearing. In sound transmission considerations, any building component (or a combination of components), such as a wall, door, window, roof or floor-ceiling assembly, that separates one space from another.

Perimeter Trim - Components of right angle shape, either simple or compound (stepped) bends, set at the suspension grid perimeter, flush to the abutting vertical surface.

Plenum - In suspended ceiling construction, the space between the suspended ceiling and the main structure above.

R Factor - A number measuring a material's 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 F (24 C), and as the inverse of BTU/hr o sf o F (imperial units), and Watts/m2 o C (metric units).

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 22 x 22 and 22 x 42 panels look like 123 x 123 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 Scrubbability Test ASTM D 2486.

Seismic Load - The force produced on a structural mass owing to its acceleration, induced by an earthquake.

Square Edge - Edge design for acoustical panels which, when viewed in profile, forms a rectangle. Though they are the simplest and least expensive to manufacture, square-cut acoustical panels do the least to hide the suspension grid.

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 C (60 to 85 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 HumiGuard ceilings. Anticipate lower overlaid thermal/ acoustic insulation (commonly referred to as "backloading") limits for these designs.

Thermal Resistance - Where thermal resistance is required for an acoustical ceiling assembly, provide adequate ventilation to avoid high humidity conditions in the ceiling plenum that could damage assembly components. Thermal insulation above the ceiling plane may place the dew point within the ceiling plenum, increasing the potential for damage to ceiling components due to condensation. When in doubt, consult a professional engineer for venting recommendations. Note: Thermal insulation overlaid on the back of suspended ceilings may cause panel deflection and limit access to the ceiling plenum. Verify limitations with manufacturer. Caution: Most tested fire-resistance-rated acoustical ceiling assemblies prohibit the use of overlaid insulation. Adding this component runs the risk of voiding acceptability of the tested assembly.

Tile - Acoustical ceiling board, usually 123 x 123, which is stapled, cemented or suspended by a concealed grid system. Edges are often kerfed and cut back.

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.

Vector Edge - An edge design that provides downward accessibility. The Vector edge detail provides a thin 1/43 reveal resulting in a clean upscale visual.

Washable - For applications where cleanliness is important, acoustical units may require cleaning beyond normal maintenance procedures. Acoustical panels with special surfaces such as DUNE, ULTIMA, OPTIMA and VPO coatings offer superior wash resistance without compromising panel finish integrity. The accepted test procedure is the Washability Test ASTM D 4828.

Application Standards

ASTM A 641 - Standard specification for zinc-coated (galvanized) carbon steel wire (aka hanger wire).
ASTM A 653 - Standard specification for steel sheet, zinc-coated (galvanized) or zinc-iron alloycoated (galvannealed) by the Hot Dip Process.
ASTM B 117 - Environmental performance test method.
ASTM C 367 - Test methods for strength properties of prefabricated architectural acoustical tile or lay-in ceiling panels.
ASTM C 423 - Standard test method for sound absorption and sound absorption coefficients by the reverberation room method.
ASTM C 518 - Standard test method for steadystate heat flux measurements and thermal transmission properties by means of the heat flow meter apparatus.
ASTM C 522 - Test method for airflow resistance of acoustical materials.
ASTM C 635 - Standard specification for metal suspension systems for acoustical tile and lay-in ceilings.
ASTM C 636 - Standard practice for installation of metal ceiling suspension systems for acoustical tile and lay-in panel.
ASTM C 645 - Standard specification for drywall furring products.
ASTM D 1037 - Standard test method for evaluating properties of impact resistance.
ASTM D 2486 - Standard test method for scrub resistance of painted surfaces.
ASTM D 3273 - Standard test method for resistance to growth of mold on the surface of interior coatings in an environmental chamber. ASTM D 4828 Standard test method for practical washability of organic coatings.
ASTM E 84 - Test method for surface burning characteristics of building materials (aka 25-foot tunnel test for smoke and flame spread on an individual product, not an assembly).
ASTM E 90 - Method for laboratory measurement of airborne sound transmission loss of building partitions.
ASTM E 96 - Standard method for testing of water vapor transmission.
ASTM E 119 - Standard methods of fire tests of building construction and material (aka hourly fire resistance rating test for an entire assembly).
ASTM E 136 - Standard test method for behavior of materials in a vertical tube furnace (aka combustibility test method; often used for Coast Guard applications).
ASTM E 176 - Standard terminology relating to fire standards.
ASTM E 580 - Standard practice for application of ceiling suspension systems for acoustical tile and lay-in panels in areas requiring seismic restraint.
ASTM E 795 - Standard practices for mounting specimens during sound absorption tests.
ASTM E 1110 - Standard specification for the determination of Articulation Class.
ASTM E 1111 - Standard specification for measuring the inter-zone attenuation of ceiling systems.
ASTM E 1130 - Standard test method for objective measurement of Speech Privacy in open offices using the Articulation Index.
ASTM E 1264 - Standard for the classification of acoustical ceiling products.
ASTM E 1414 - Standard test method for airborne sound attenuation between rooms sharing a common ceiling plenum (previously known as ASTM E 413).
ASTM E 1477 - Standard test method for luminous reflectance factor of acoustical material by use of integrating-sphere reflectometers (previously known as ASTM C 523).