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1950-51 Theatre Catalog, 9th Edition, Page 140 (120)

1950-51 Theatre Catalog, 9th Edition
1950-51 Theatre Catalog
1950-51 Theatre Catalog, 9th Edition, Page 140
Page 140

1950-51 Theatre Catalog, 9th Edition, Page 140

Fire-Safe Fiberglas Board and Tile

New Incomhustible Material Answers the Need for Deadening Sound in All Parts of Theatre I .


Just how a material absorbs sound is still not fully understood, but it is believed that friction of the pulsating air molecules against the interstices of porous materials transforms sound energy into heat, and that it is in this way that most sound absorption is provided. If this theory is correct, it follows that, within limitations, by increasing the total surface area provided by a material, the noise absorption value can be increased.

Total surface area of a porous fibrous material can be increased by decreasing the diameter of the fibers that make up the material. Further research may demonstrate that acoustical values are functions of fiber diameter, and of the surface area of the fibers. This theory would account for the performance of Fiberglas as an acoustical material. A pound of glass fibers with an average diameter of 5 one-hundred-thousandths (0.00005) of an inch has 36,000 times the surface area of the same amount of glass in the form of a sphere.

All Fiberglas products used for acoustical purposes are made of a basic inorganic material#glass in fiber form. Glass is born of great heat and flame-so intense that sand, limestone and other mineral components are melted and blended in a formula designed to give maximum chemical and physical stability. In the manufacturing process, molten glass is drawn into fine fibers under carefully controlled techniques. When combined with a small percentage of a


Acoustical Specialist Owens-Corning Fiberglas Corporation Toledo. 0.

BRIEF: A theatre may have the best sound system in the world . . . but it cannot function at top efficiency if proper provisions are not made to deaden echoes, vibrations, and other sounds . . . which will prevent the audience from hearing clearly the voices in the picture . . . Acoustics, therefore, should be given priority consideration in new construction or remodeling.

The combustible characteristics and weight of many rigid acoustical products have compelled theatre operators to turn to plaster compounds and bulk soundabsorbing products . . . although the latter are primarily intended to serve as thermal insulators . . . Unfortunately, however, plaster has required frequent patching and loses some of its absorption qualities with age . . . and bulk materials have proven too heavy to support with ease.

In short, there has been a crying need for an acoustical product which would possess high sound-absorption qualities . . . yet be hre-safe, light in weight, and dimensionally stable . . . The solution to this vexatious acoustical problem seems to have appeared at last with the advent of Fiberglas board and tile . . . which not only provides all the desirable features mentioned above, but is also a good durable thermal insulator as well as a sound deadener.

AN INTERESTING CEILING of Fiberglas tile as found in the lounge of the Brynwood Country Club. Milwaukee, Wisconsin. Applied by mechanical method it produces desired acoustic results and adds beauty.


highly stable binding agent, Fiberglas fibers are compressed and bonded into a board or blanket form. From these forms are made Fiberglas acoustical tile and board and other Fiberglas products employed for sound control.


Not only auditorium acoustical requirements, but also the low noise level requirements in lobbies, lounges, foyers and rest rooms, make acoustical treatments a major consideration in both new theatre construction and remodeling. The combustible nature and/or weight of most rigid acoustical products have forced theatres into the use of plasters and the concealed use of bulk soundabsorbing materials designed primarily for thermal insulation purposes.

Because the new Fiberglas acoustical tile and board are free from the two basic objections to most rigid productse combustibility and excessive weightthey are expected to find wide use in theatres. Designed for good architectural appearance, and painted white for good light diHusions, the Fiberglas products provide a low-cost, light-weight, incombustible ceiling or wall material with high sound-absorbing properties. The board, and plain or perforated tile, can be cemented to a solid backing or mechanically mounted on wood or metal fur-ring strips.

Acoustical Requirements

In determining acoustical requirements of such spaces as auditoriums, it is common practice to consider reverberation at the one frequency of 512 vibrations per second. Spaces requiring critical analysis, in which the acoustical treatment must provide most of the sound absorption, may show excessive reverberation at low frequencies even though conditions may be satisfactory at 512 cycles. Because many Fiberglas products provide exceptionally high absorption at low frequencies, they are particularly well suited for use in radio and television studios and other spaces requiring Hstraight line" absorption for good results.

Advantages of Fiberglas

The incombustibility of Fiberglas acoustical tile and board shares with high-sound absorption efficiency major credit for the rapidly expanding use of these materials, particularly in places of public assembly where experience has shown that combustible acoustical materials constitute a serious fire hazard.

Both the tile and board are rated ffincombustible'i when tested according to the exacting procedure specified in Federal Specification SS-A-118a. Sound absorption coefficients for the plain tile

1950-51 Theatre Catalog, 9th Edition, Page 140