This project is located within the 65 CNEL Aircraft Noise Footprints based upon the Federal Aviation Administration (“FAA”) 1983 CNEL Noise Exposure Map. If the properties within this map is constructed after Jan. 1st 1983, or is renovated at a cost equal to 25% or more of the current market value of the home, it must be insulated against aircraft noise to meet FAA noise insulation program standards. This means that the windows must have a Sound Transmission Class (or STC) rating of 35. A typical interior wall with one layer of 1/2″ gypsum board on each side of wood stud at 16” on center has an STC of approximately 33.
The window manufacturer we selected cannot provide STC 35 certification as a whole window assembly but the glass itself will perform the STC rating of 30 – 35. We explained the situation with the building official and were able to obtain approval with the glass specification.