Keystone was founded as a National Fenestration Rating Council (NFRC) licensed Inspection Agency in 1998 by Former President, Marcia Falke, building on her more than 25 years experience in fenestration testing & certification. Since then, Keystone has added numerous certification, inspection and quality assurance programs focused on energy efficiency and structural quality. Our programs are utilized in a wide variety of product categories ranging from building products to appliances.