Nailor Model 0722 Ceiling Dampers are for use in spherical programs, in lieu of hinged doorway type dampers in any UL/ULC floor/ceiling or roof/ceiling assembly with as many as a 3 hour hearth resistance score where air ducts are permitted. Google aims to really make it easier to keep educated by making use of https://dampersforindustrialsecto25677.p2blogs.com/35557958/the-2-minute-rule-for-dampers-for-industrial-sector