Specifications

18
Natatorium DesigN maNual
3. Supply air to the remainder of the room to ensuring
there are no stagnant areas.
4. Locate the return duct where it will optimize the entire
airflow pattern.
5. Prevent air short-circuiting by avoiding supply air
diffusers near the return grille.
The following sample duct diagrams illustrate good air
distribution practices:
All air distribution systems should:
• Satisfy ASHRAE design requirements and local
codes.
• Supply at least 4-6 volumetric air changes per hour.
• Blanket exterior windows, exterior surfaces and other
areas prone to condensation with supply air. A good
rule of thumb is 3-5 CFM per ft2 of exterior glass.
• Locate the return grille to enhance the overall air
pattern within the room.
• Select grilles, registers and diffusers that deliver the
required throw distance, and the specified
CFM rating.
• Introduced outdoor air per local codes and/or
ASHRAE Standard 62-2004.
• Maintain a negative pressure in the space with an
exhaust fan.
General Recommendations:
• Galvanized sheet metal ducts are acceptable in
most installations. A below-grade duct system should
use PVC or plastic-coated galvanized spiral pipe to
avoid deterioration.
• Fabric duct is an excellent choice of duct material
for a Natatorium. The duct material should not allow
air to leak. The location of supply grilles and overall
duct layout should be exactly as you would with
metal duct.
• Ductwork that passes through an unconditioned area
should be insulated on the exterior.
• When applicable, locate exhaust fan air intakes as
close to the whirlpool as possible.
• To prevent excessive vibration noise, install neoprene
flex connectors when attaching ductwork to the
dehumidifier. Acoustic insulation on the duct close to
the unit may also be a consideration.
• Skylights require significant airflow to avoid
condensation on their surfaces.
Figure 9 – Window Design
Figure 10 – Perimeter Duct Layout
Figure 11 – Perimeter Below-Grade Duct Layout