Firestop Pillow
This information reflects our best understanding of product composition in 2022.
Firestop pillows or cushions are generally comprised of an insulating, heat-resistant core surrounded by an intumescent material and sealed in an exterior bag. There is variability across manufacturers in the materials used for each layer. This CP...
Firestop pillows or cushions are generally comprised of an insulating, heat-resistant core surrounded by an intumescent material and sealed in an exterior bag. There is variability across manufacturers in the materials used for each layer. This CP covers firestop pillows with an insulating core made of mineral wool surrounded by an intumescent coating and encapsulated in a polyethylene bag. Another common type of firestop pillow not covered by this CP contains loose organic filler and intumescent material in a glass cloth bag, which may be coated with PVC or other water resistant coating. These pillows are compressed and stacked to fill through-penetrations in need of firestopping. Most do not require adhesives to affix the pillows in the penetration, allowing pillows to be moved and reused. This is particularly useful in areas that require frequent access or retrofitting (e.g. cable trays, electrical conduits, etc.). Upon exposure to fire, the intumescent material expands to seal the through-penetration and stop the spread of smoke and fire. This Common Product describes firestop pillows containing an intumescent coating based on expandable graphite, though various chemistries may be used to provide intumescence. See the All Contents tab for additional chemicals that may be used in these intumescent coatings.