Modernfold Acoustical Guide
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Acoustical Guide Operable Partitions Making A Sound Decision In Operable Partitions Introduction Acoustical control is a critical factor in virtually every type of environment; therefore selec­ion of the appropriate t oper­ ble partition is critical. a It’s important when choosing an operable wall system to not only consider the space/configuration of your application and how the wall operates, but to also examine the wall’s acoustical performance. The right wall system, in conjunction with complementing architectural elements, can help produce excellent acoustical control. When selecting a wall system, several questions need to be asked relative to the room-to-room noise reduction. Also to be addressed is the need for the operable partition to provide a sound-absorbing surface in the rooms formed by the partitions. What degree of acoustical control will you need? What does it take to attain it? Which wall system is better for your needs? What architectural elements of the project should be considered? The industry accepted “measuring stick” for the acoustical performance of operable walls is the Sound Transmission Class (STC) rating. Walls are tested under laboratory conditions with varying frequencies (125-4000 cycles per second) to deter­ ine how much a sound level decreases m when it transmits from one side of the wall/partition to the other. This decrease is called Transmission Loss (TL). For instance, if a sound measures at 70 dB on one side of a parti­ion, and only t 40 dB on the other, the TL rating would be 30 dB at that particular frequency. Since common sounds cover a wide range of frequencies, Sound Transmission Class (STC) ratings are used to provide a single number rating to identify the Transmission Loss of a partition as it varies with frequency. A higher STC rating indicates higher transmission loss, a desirable attribute of the partition. There are several Modernfold Wall Systems available with STC ratings to meet most acoustical control applications. For comparison, see how the Modernfold systems rank with some typical fixed wall systems. Modernfold developed this guide to answer these and many other questions. If you need more information, call us at 800-869-9685 or email info@modernfold.com. Anticipate Sound Levels In order to effectively specify a system to control/reduce the sound/noise in an environment, you must first identify the types and levels of sounds you are trying to control. Then, decide on what degree of “acoustical privacy” is necessary in your facility. What sound levels are likely to be generated by functions using the rooms formed by the operable partitions? How much low frequency energy will there be in the generated sound? What sound levels are permissible on the “other side” of the operable partition? Typical Sound Pressure Levels Levels in dBA Common Sounds Short Exposure can cause Hearing Loss Jack Hammer Thunder Riveting Machine Hard Rock Band Boiler Factory Machine Shop Noisy Plant Printing Press Kitchen Equipment Sports Car Interior (50mpg) 6-Piece Orchestra Amplified Speech Noisy Office Speech Average Factory Average Radio Normal Conversation Average Business Office Average Residence Quiet Radio Private Office Average Auditorium Quiet Conversation Sound Stage (Movie) Very Faint The Typical Sound Pressure Levels chart indicates the sound-pressure levels of many everyday sounds. Sound levels are expressed in decibels (dB). The decibel scale ranges from zero (the threshold of audibility or the ability to hear) all the way up to 120 dB (the threshold of ear pain) and beyond. The chart can be a practical way to help gauge the sound levels of your environment. The chart indicates sound pressure levels in dBA—sound levels measured on the A scale of a sound level meter. The A scale minimizes the effect on the measurement of sound at low frequencies. Very Loud Intolerable for Phone Use Sound Proof Room Human Breathing Please contact your local Modernfold distributor for further assistance, or visit our website at www.modernfold.com.

Acoustical Guide Operable Partitions Sound Transmission Class (STC)* Partition Thickness Partition Surface Weight (PSF) 1.75-inch Hollow Core Door 25% Louvered 1.75-inch Hollow Core Work Door No Gaskets 1.75-inch Solid Wood Door Fully Gasketed .50-inch Gypsum Board ea side 2x4 Wood Studs .62-inch Gypsum Board ea side 2x4 Wood Studs 4 Layers .62-inch Gypsum Board Wall .25-inch Acoustic Glass (Laminate) 6-inch Painted Concrete Block 2 Layers .50-inch Gypsum Board ea side Metal Studs 2 Layers .50-inch Gypsum Board ea side Metal Studs w/ Cavity Insulation 8-inch Brick Wall w/ .50-inch Plaster...

Acoustical Guide Operable Partitions A DORMA Group Company Above the Partition Track (Figure 1) A plenum above a partition can allow sound to pass up through the ceiling on one side and down to the other side. To eliminate this problem, a barrier (with a sound transmission loss equal to or greater than the partition) should be created above the partition. Often times air ducts will penetrate plenum sound barriers. Such ducts will lower the transmission loss of the plenum barrier since sound will be transmitted through the thin wall of the duct on one side of the barrier, through the duct,...

Acoustical Guide Operable Partitions Field Sound Tests (NIC& FSTC) The field performance of a building’s operable wall is covered by ASTM E-336. Field test results are calculated according to ASTM E-413 and reported as Noise Isolation Class (NIC) or Field Sound Transmission Class (FSTC). It should be noted that NIC ratings are determined using Noise Reduction (NR) data, the arithmetic difference between sound levels in the sending and receiving rooms. NIC ratings are dependent upon the amount of soundabsorbing material in the receiving room and the size of the operable wall. FSTC ratings...