The LVH intumescent air transfer grilles available from Lorient Pty Ltd are specifically designed for use in fire rated door assemblies where pressure relief or extra ventilation is required.

In normal ambient conditions, LVH intumescent air transfer grilles provide free airflow. However, when exposed to elevated temperatures, the intumescent material in the slats expands to create a physical barrier to fire as well as hot smoke, ensuring ample protection to building occupants.

These intumescent fire door grilles have been fire tested in accordance with AS1530.4 on most AS1905.1 proprietary fire door types, providing up to 4 hours of fire resistance. 

Read Grill Sizing and Approved Fire Resistance Ratings at this link.