mechanical3010
Mechanical
For UL Listed Type B Fire dampers (in which the fire damper mechanism in the Hat section extends on the top whereas all its other three sides inside the sleeve are the same size as the duct. As per standards for type B, the minimum gauge thickness of the sleeve must be the same as the gauge of the duct to which it is attached. The gauge thickness of the duct is governed of course by SMACNA standards. The duct gauge for small sized ducts (14 inches) the gauge thickness for low pressure ducts (1/2 inch W.G. Static pressure) is gauge 26. Is it permissible to use the same gauge thickness of 26 for fire damper sleeves or is there a minimum gauge thickness for sleeve of type B fire dampers also, as gauge 18 is the absolute minimum for type C fire dampers? Likewise if the duct gauge is 22 can the sleeve be gauge 22 also or there is a minimum gauge.
