The roof ventilators shall be of the Heritage  Ultra vertical exhaust series as designed  and manufactured by Fantech Pty. Ltd and be  of the model numbers shown on the  schedule/drawing.
The cowl shall be of galvanised steel unless  specified otherwise. Impellers shall be Mixed-Flow  design and driven by standard TEFC motors  unless specified otherwise.
The windband shall incorporate quick-release  toggle clamps to provide easy access for  cleaning and maintenance.
All models shall be fully tested as a complete  assembled unit to ISO5801: 2007 for air flow.  Noise tests shall be based on ISO13347-3