How is a certification of STC rating obtained?
A. To receive a Sound Transmission Loss test report, a manufacturer must arrange for a testing session in an acoustical laboratory. The laboratory must be accredited by the United States Department of Commerce, National Institute of Standards and Technology (NIST) under the National Voluntary Laboratory Accreditation Program (NVLAP) for test procedure. A laboratory test assures that the manufacturer’s door or window performs to a specified STC rating.
