Specifications

29
ENVISION COMMERCIAL SPECIFICATION CATALOG
Acoustical Considerations and
Equipment Sound Performance
Sound Performance
The Envision Series is third party sound rated in
accordance with ARI 260. Please consult WaterFurnace
Sound Performance Data Catalog for details on the ARI
standard and sound performance data.
Recommendations for Noise Reduction
Horizontal Unit Location
Specify equipment with quietest sound power ratings•
Do not locate units above areas with a required NC 40 •
or less
Space WSHP at least 10 ft (3m) apart to avoid noise •
summing of multiple units in a space.
Maximize the height of the unit above the ceiling •
(horizontal).
Suspend unit with isolation grommets that are •
appropriately rated to reduce vibrations (horizontal).
Vertical Unit Location
Specify equipment with quietest sound power ratings•
Space WSHP at least 10 ft (3m) apart to avoid noise •
summing of multiple units in a space.
Acoustic ceiling coatings can greatly reduce noise levels •
in mechanical rooms.
Mount unit on a sound absorbing pad, extruded •
polystyrene, rubber or cork pad.
Ductwork
Insure return air grilles will not allow line of site noise to •
transfer to adjacent space. Use a sound barrier or some
other material to isolate the grille from the unit. A
supply grille, boot and short piece of flex duct pointed
away from the unit can greatly attenuate equipment
noise.
Use a canvas isolation duct connector at the supply and •
return duct connection of the unit.
Internally line the discharge and return duct within the •
first 4-8 feet of unit with acoustic insulation. Install an
internally lined ‘L’ shaped return duct elbow at return
grille. Face the elbow away from adjacent units.
Always install at least one 90° elbow in the discharge •
duct to eliminate line of sight noise transmission of the
blower.
Use turning vanes at all elbows and tees to reduce •
turbulence.
Limit supply duct velocities to less than 1000 fpm•
Design and install ductwork as stiff as possible•
Allow 3 duct diameters both up and down stream of •
the unit before any fittings or transitions are installed.
Use duct sealant on all duct joints.•
Install a short (2-4’) of flex duct on all branch ducts just •
prior to discharge boot or diffuser to reduce vibration
and duct sound prior to delivery in the room.
Locate the branch duct balancing damper as far away •
from the diffuser as possible.
In ceiling plenum systems, install an internally lined ‘L’ •
shaped return duct elbow at unit. Face the elbow away
from adjacent units (horizontal).
Envision Application Notes cont.
Insulated Return
(optional)
90 deg elbow
on supply
Flexible water
and electrical
connections
Acoustic lining
to elbow
Turning vanes
at elbows and
Tees
Branch
damper
upstream
Flex duct
at diffuser
2-4 ft
Sealed low
velocity
ductwork
Supply grille
with 2-3 ft of
flex left open
for return air
Locate units over
hallways where
possible
Canvas
connector
Locate return grille
6 ft from unit