Indoor Pool Ventilation
Indoor swimming pools continuously produce large quantities of chlorine laden water vapour through the process of pool evaporation.
The effects of this evaporation are magnified by the fact that the construction industry keeps building more energy efficient tighter structures.
When water vapour has no escape from these air tight structures, it causes numerous problems such as:
rust, blistering of paint, deterioration of structural supports and many other negative cosmetic effects on your building.
As a result repair or replacement of damaged items can be very costly and time-consuming. Patrons and staff of indoor pools must also endure an unpleasant environment. They are surrounded in the physical discomfort of high humidity. The mold, mildew, bacteria and fungi that grow in these moist conditions can affect their health. These growths give off low-molecular weight volatile organic compounds (VOCs), many of which are poisonous and have potent odors.
Bathhouses, mechanical equipment rooms, storage areas and indoor swimming pool enclosures shall be ventilated, either by natural or mechanical means. Room ventilation shall prevent direct drafts on swimmers and shall minimize condensation. A minimum of two air changes per hour shall be provided for indoor pool areas. Heating units shall be kept from contact with swimmers. Fuel-burning heating
equipment shall be installed and vented to the outdoors in accordance with the Uniform Code.
CALCULATION OF VENTILATION REQUIREMENTS FOR INDOOR POOLS BASED ON MOISTURE EVAPORATION
In general , it may be said that a mechanical ventilation rate of 1 ACH (one air change per hour) of the pool enclosure will be sufficient to maintain reasonable relative humidity levels when a pool cover is used regularly. However, the ventilation system should be capable of supplying 2 (two) ACH for maintenance of good air quality in all operating conditions.
MOISTURE PRODUCTION OF INDOOR POOLS:
The amount of water evaporated from a pool depends on:
a) the surface area of the pool;
b) the water temperature;
c) the indoor air temperature and relative humidity;
d) the amount of air movement over the pool surface.
In short, the following principles apply:
1) The larger the water surface area, the greater the amount of water evaporated. Therefore, using a pool cover to reduce the surface area of water exposed reduces the amount of water evaporated;
2) The higher the water temperature, the higher the evaporation rate;
3) The lower the indoor air temperature, the higher the evaporation rate;
4) The lower the indoor relative humidity the higher the evaporation rate;
5) The greater the air movement over the pool area, the higher the evaporation rate. Thus, activity in the pool area will increase the evaporation rate.