Controlling Humidity Through Proper Air Distribution

Efficient dehumidification will not take place if the air distribution system is designed improperly. Careful consideration must be given to the location of supply air ducts, the location of the air return grill, use of moisture barriers and door and window insulation values. By combining the proven results of a PoolPak system along with good duct design, you can be assured of maintaining a safe and pleasant environment for many years.

The objective of an air distribution system within a high moisture environment such as an indoor pool facility is to maximize airflow of warm, dry supply air over any surface that is prone to condensing temperatures, including all walls, windows and skylights.

An indoor pool requires space air heating 70% to 90% of the year. Therefore, the most effective air distribution system is one that takes advantage of hot air's natural tendency to rise. This type of system will supply the air "low" and return it "high.

Below Grade Ducting

Supply air ducts must be located below grade around the inside perimeter of the enclosure for low set windows and sliding glass doors.
Ducts should be constructed of a non corrosive material such as PVC or galvanized steel.
Linear slot diffusers must be positioned to blanket the glass surfaces and outside.
Below grade ducting prevents the migration of cooler air down the wall and across the floor, reducing the incidence of cool dead air spaces that may form on windows or walls

Soffit Ducting

Use when it is not possible to supply the air low and return high.
The supply air grill must be located close to the windows, preferably within twelve inches from the surface.
Direct 80% of the supply air down the walls with the remainder directed along the ceiling to break up any stratification and stagnation occurring near the ceiling.
Airflow should never be directed over a pool surface since this leads to bather discomfort and excessive evaporation.
Flood skylights with supply air through ducting, or use ceiling fans as an alternative if ducting is not available.

Typical Room Layout

Efficient dehumidification requires a well balanced and properly placed ducting system.
Never position ducts in a way that will result in short cycling of the supply air.
Position the return inlet(s) so that all of the moist, warm air flows efficiently back to the dehumidification system, eliminating dead areas where air stagnation can occur.
Locate a single return duct about 10 - 15 feet above the floor to capture the rising moist air.
Airflow over or too near the pool will speed evaporation and limit the dehumidification system's effectiveness. The greater the velocity, the greater the evaporation process.

Vapor Barriers

Vapor barriers should be installed immediately behind the interior wall surface.
The dew point must be reached on the cold side of the vapor barrier where moisture is not present.
Always seal barrier joints around switches and receptacles to prevent localized moisture migration.

For this and other brochures, follow the Get A Brochure link.