NAC Products’ Super SAM 125 Sound Control Membrane has achieved an IIC rating of 51, Delta IIC rating of 22 and an STC rating of 54 on a bare, 6” concrete slab, according to the company. Most building codes call for minimum IIC and STC ratings between 45 and 50. 
Architectural Testing was contracted by NAC to conduct the acoustical tests, which were performed in accordance with standards ASTM E 492, ASTM E 2179 and ASTM E 90. 
According to the company, Delta IIC is the most accurate measurement of the membrane system and is determined by taking the measurement of the floor assembly prior to the installation of the acoustical membrane system. The same test is then conducted with the membrane system in place. The difference between these measurements is the Delta IIC rating.
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