Is Foil Faced Polyisocyanurate Foam Insulation Hazardous when Used Indoors?
Are there any health hazards associated with applying rigid foil-faced polyisocyanurate insulation on the inside of the existing walls of a living space? I am aware that these insulations give off toxic gases as they burn. The question in my mind is whether they are safe on a day-to-day basis within the building envelope with an air change rate of say 0.75 ACH per hour? — R.H. Mendocino CA Our photograph (above left) shows Celotex Super Tuff-R polyisocyanurate insulating board used indoors. Answer: Rigid polyisocyanurate insulation is foamed from freon gas, a fluorinated hydrocarbon often used as a refrigerant and until the early 1980’s, as a propellant in aerosols. [Currently non HFC gases are used for foam insulation production –DF] The earlier-used Freon gas family and modern refrigerants are inert gases and are considered non-toxic, except in very high concentrations of over 1000 ppm [at which point even an inert gas can cause asphyxiation]. The small quantities of gas that will
