Life-safety dampers (inset, photograph courtesy of Greenheck) prevent the spread of flames and/or smoke during a fire event, facilitating occupant evacuation. Credit: Wittybear/Shutterstock HVAC systems intended to remain operational during a fi re. They are designed to operate under airfl ow and static pressure and to close when the temperature reaches a certain threshold. When do I use a 1.5-hour fi re damper, and when do I use a 3-hour fi re damper? NFPA (National Fire Protection Association) 90A, Standard for the Installation of Air-Conditioning and Ventilating Systems, states penetrations in barriers rated for less than 3 hours must be protected with fi re or combination fi re/smoke dampers rated for 1.5 hours. Penetrations in barriers rated for 3 hours or more must be protected with fi re or combination fi re/smoke dampers rated for 3 hours. www.amca.org Does the penetration for a fi re damper in a fi rerated wall need to be framed? Yes. All metal- and wood-framed fi re-rated walls have framing requirements for openings in which a fi re damper or a combination fi re/smoke damper is to be installed (Photo A). Manufacturer installation instructions shipped with dampers and usually available online show or have a link to standard framing details. Which type of heat-responsive device should I use, a fusible link or a thermostat? Fusible links typically are found on curtain and multiblade fi re dampers, while thermostats mostly are found on combination fi re/ smoke dampers. 2022 AMCA inmot ion 13http://www.amca.org