Alva-Therm is a thin intumescent cellulose based sheet that on exposure to flame and heat the material begins to expand in a unidirectional manner. Expansion begins between 350ºF and 400ºF with substantial expansion occurring above 450ºF. The material rapidly expands as temperatures exceed 500ºF and continues to expand up to 1000ºF. As the material expands in a confined area it will compact and form an insulating char to retard the spreading of flames and to control temperature increases.
This thin intumescent firestop sheet can work well as a gasketing material when intumescence is required, and may be layered to increase the overall thickness. Some possible applications might be for fire door seals, through penetration boxes or enclosures containing communication cables or other items.
Physical Properties
| Color | Dark Brown to Black |
| Dimensions | 0.040″ thick material on Rolls 28″, 36″, or 40″ wide |
| Minimum Weight | 50 grams per square foot |
| Expansion Begins | 350ºF - 400ºF |
| Volume Expansion | @500ºF, 10X-12X |
