The 2015 International Code Council made changes in the IMC & IBC that he 2015 I ernational Code Council require the use of dynamic ceiling radiation dampers in HVAC systems made changes in the IMC & IBC tha equire the use of dynamic ceiling adiation dampers in HV C systems that remain on in an event such as a fire. that remain on in an even such as a fir DynaGuard dynamic ceiling radiation dampers are the only dampers to protect a ceiling from failing while air is being forced or pulled through it. ynaGuard dynamic ceiling adiation dampers are the dampers to protect a ceiling from failing while air is being or ed or pulled through it DynaGuard is installed in UL approved field fabricated boots. appr ynaGuard is installed in UL ed field fabrica ed boots Metal-Fab uses traditional frame designs to ensure consistent boot damper fittings damper fittings. etal-Fab uses traditional frame designs to ensure consistent boot Dynamic Ceiling Radiation Dampers in boot assemblies for use in UL fire resistance floor-ceiling & roof-ceiling designs as listed in the UL fire resistance directory. Metal-Fab ceiling radiation damper assemblies are classified and compliant to ANSI/UL263 testing requirements. Metal-Fab ceiling radiation dampers are 1-hour rated as a DYNAMIC ceiling radiation damper for the following UL approved ceiling/floor and ceiling/roof assemblies - M557 & P581 http://www.mtlfab.com/dynaguard