PROMASTOP®-IM Grille is an intumescent sealing system for ventilation openings. Each grille is a single element that can be slid into another to accommodate any opening size. The expansion activates at approximately 190 °C to seals the opening against the spread of smoke and fire. It has been tested to provide up to 240 minutes of fire resistance in ceilings and up to 120 minutes in walls.

Visit link to find out more: https://www.promat.com/en-sg/construction/products-systems/products/fire-stopping/others/promastop-im-grille/