Security Metal Doors Each of metal-doors.net assemblies, which have achieved the highest Sound Transmission Class (STC) ratings within the industry, have been tested at Riverbank Laboratories, an independent acoustical laboratory qualified under the National Voluntary Laboratory Accreditation Program (NVLAP). Our 1-3/4ö metal doors are available with an STC rating up to 53. Our 1-3/4ö wood doors have achieved an STC rating up to 50. Our window frames have been tested with an STC rating of up to 57. Metal Doors and Frames |
