The collar attached to this plate houses and supports strips of material which expand when the activation temperature is exceeded. Once the material has expanded to the flue outer casing, the assembly maintains the fire resistance of the structure through which the flue passes.  The Ventilated Fire Stop with Fire Sealing Collar is designed to meet the requirements of The Building Regulations 2000 Approved Document B and has been tested to comply with the requirements of BS EN 1856-1.