Swimming Pool Operation, How does a swimming pool work

Swimming pool operation speaks to how does a swimming pool work.

It is of utmost importance that swimming pool operation be strictly adhered to when dealing with pressurization, air temperature, water temperature and relative humidity control of the pool.

Swimming pool regulations state that normal desired controlled conditions are:

Pool air temperature 87 F. Pool water temperature 85 F. Pool relative humidity 50%RH.

It is necessary that the pool air temperature be 2 F degrees higher than the pool water temperature. This will inhibit condensation forming on the walls and windows.

The pool area must be controlled at a negative pressure relative to outside and to adjacent areas in the building. Air must migrate from outside and from adjacent areas into the swimming pool area.

If swimming pool operation regulations are not followed the pool will be controlled at a positive pressure and air will migrate to outside from the swimming pool. This will amplify any building structural and envelope deficiencies.

Condensate will form on the outside of the perimeter wall and cause water to drip down the wall. This will cause deterioration of the building wall.

If swimming pool operation regulations are not followed the pool will be controlled at a positive pressure and air will migrate to adjacent areas in the building. This will result in the growth of bacterial mold above the suspended ceiling and in enclosed spaces with poor ventilation. Bacterial mould is most detrimental to human beings.

For bacterial mold to grow three conditions must exist:

Heat is required. Moisture is required. Nourishment is required and this can be any construction material that contains minute amounts of starch.

Normal ambient air relative humidity levels in a building are 30% to 35%. Swimming pool ambient air is controlled at 50% relative humidity.

The air system which serves the pool area must be air balanced to certain design criteria to ensure that the pool area is negative.

For example:

Supply air to the pool is 2000 cubic feet per minute (cfm). Return air from the pool should be 1800 cfm. Outside air to the pool should be 200 cfm.

Exhaust air from the pool should greater than the outside air perhaps 500 cfm. The rate of exhaust can be set to achieve specific air changes in the pool based on the rate of exhaust air volume of the pool room.

It is suggested that the exhaust air fan should be equipped with a fan speed control to allow for a correct air balance of the pool area.

The pool return air grille should be of an adequate size so that there is no high velocity air noise at the grille. If the air volume returning through the grille exceeds 700 feet per minute there will be noise.

The pool air system will consist of:

  • Return air grille.
  • Outside air intake.
  • Cooling coil (dehumidification).
  • Reheat coil.
  • Supply fan.
  • Supply air diffusers.
  • Automatic controls. It is important that the primary side of the heat exchanger which heats the pool water be supplied with boiler water at a constant temperature of 180 F. It is also important that the air system reheat coil be supplied with boiler water at a constant temperature of 180 F. The boilers supplying the heating water cannot be controlled using an indoor/outdoor rest schedule. Using this control theory as outdoor air temperature increases the boiler supply water temperature decreases. This is not acceptable for pool systems.
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