Keene Building Products' QUIET QURL MT "Muffler" sound mats were recently used in the Camden Commons condominium complex in Franklin, Tenn. The Muffler product is designed to improve the IIC level by as much as seven points, according to Keene.

In the lab, the performance of the Muffler product was 20 dB better at the high frequencies than standard, code complaint QUIET QURL. Additionally, the performance in the low frequencies (down to 125 Hz) was improved by 5 dB.

In the Camden Commons project, field tests showed bare gypsum concrete with an AIIC (Apparent Impact Insulation Classification) of 58, vinyl plank performance of as high as 60 and engineered wood performance as high as 64 AIIC. Keene said those numbers greatly exceed normal 0.25" sound mat performance in wood frame. All tests were conducted by independent acoustical consultants and testing companies.

Keene's patent pending MT Muffler is designed to compress into the interstices of the entangled net mat. The "highloft" fabric is heat laminated to the bottom side of the core adding almost no additional thickness to the sound control mat when loaded with a 1.0" to 1.5" underlayment. Keene has developed a method of reinforcing the gypsum concrete with a combination fiberglass scrim and fabric designed to add as much as 20 percent to the tensile strength. The reinforcing fabric is called "RF."

Keene products used in the condo project included: QUIET QURL 55/025 RF MT, QUIET QURL Perimeter Isolation and 1.25" of Gypsum Concrete. The project developer was CODA Development, based in Nashville. The architect was Kline Swinney Architects of Nashville. Acoustical was handled by Veneklausen Associates, Santa Monica, Calif. The installer was Hico Concrete, based in Nashville.

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