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Insulated Fire Doors
     One Door - Many Benefits

Provide UL rated fire protection plus security, sound attenuation, environmental separation and smoke control with the Firemiser insulated fire door from Cornell.



Achieve Rolling Steel Security with up to 4 hours of UL Labeled Fire Protection, plus:

  • Sound Attenuation - A Sound Transmission Class rating of STC 27 makes Firemiser’s mineral wool insulated curtain an excellent choice to maintain fire wall integrity and reduce decibel levels.

  • Climate Control - Firemiser’s insulated curtain yields a 5.3 R-value that can be combined with full perimeter seals for use at exterior or interior openings whenever fire protection and environmental separation is required.

  • Smoke Control - Add optional UL labeled smoke and draft control to fire doors. Containing smoke saves lives and building property and also aids in fire containment by slowing oxygen flow to the fire source. It's simple to double up on the protection of your building and may be required by your local building code. For more information click here.

Practical Design Applications:

  • All fire wall openings where the door is to be closed regularly and a sound attenuation need exists.

  • Exterior openings that require a fire rating due to the proximity of other structures or combustible materials.

  • Buildings designed for future expansion where current exterior wall openings are to become interior fire wall openings.

  • Interior fire wall openings where the door will be normally closed to control varying climatic conditions between two areas.


4 HR, 3 HR, 1 1/2 HR, 1 HR and 3/4 HR Underwriters' Laboratory (UL) labels. Flame spread and smoke development index factors for Firemiser’s mineral wool insulation are zero.


Standard construction for openings to a maximum of 30’ wide or 22’ high. Consult factory for units over 270 square feet.

Material and Finishes:

Exterior / Interior curtain skin - galvanized steel with exclusive GalvaNex™ finish in light gray, powder coating as an available option, or 300 series stainless steel with #4 finish. Cast iron endlocks / windlocks are required per UL procedure.


Face of wall or between jambs configurations in both interior and exterior walls. Approved wall types for the mounting of insulated fire doors include masonry or structural steel jambs.


M100 motor, chain or crank operating systems are recommended for ease of testing and controlled automatic closing speed. Click on the Operator Information button at right for a full description of these systems.