• Sheet metal material type and thickness
  • Checkerplate floor
  • Access doors and access panels on both sides
  • Glass inspection windows in access doors
  • Marine lights pre-wired to wall switches
  • Factory installation of damper actuators
  • Insulated damper blades
  • Painted external finish
  • Special corrosion resistant coatings on internal and/or external surfaces
  • UV-C germicidal lamps
  • Air leakage test with written report
  • Additional drain connections
  • Electrical power package
  • Control package


  • Heavy-duty split housed bearings with minimum average life (L-50) of 400,000 hours
  • Standard or OSHA belt guards
  • Fan inlet and outlet screens
  • Protective enclosures for plenum fans
  • Special coatings
  • Motors: TEFC, high efficiency, 2-speed, inverter duty, etc.
  • Variable frequency drives
  • Inertia bases
  • Extended lube lines to lubricate both bearings from one side of the unit casing exterior


  • Fin, tube and coil casing materials
  • Fin thickness and spacing
  • Tube wall thickness
  • Special corrosion resistant coatings
  • Piping connection material