Comfort, Health and Safety

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Comfort Health Safety

  • Comfort and Health

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A natatorium is one of the most notoriously difficult facilities to design because there are so many critical considerations that, if overlooked, can develop into problems with the building structure or into complaints from the occupants. The designer must take a complete system approach, from basic engineering issues to the more subtle details in the air distribution. Experience and a complete understanding of the design issues help the designer satisfy:

  • Comfort and health
  • Humidity control
  • Indoor air quality
  • Condensation control

Comfort and Health

Temperature and relative humidity play a critical role in human comfort levels. It is essential that both are controlled and stable. While temperature control is generally well understood and mastered by designers, it is important to recognize what temperature levels natatorium patrons want. The space temperatures in a natatorium are unique to each project and assumptions must never be made.

Proper control of relative humidity levels are also a concern because of the direct effect on human comfort and health. Figure 1 shows that relative humidity levels outside the optimum zone 40% - 60% range can result in human vulnerability to disease. These diseases include bacteria, viruses, fungi, Mites and other contaminants that lower air quality and will potentially lead to respiratory issues.

While 40% is certainly an acceptable indoor relative humidity level, most indoor pools do not operate at lower than 50% RH due to significantly increased operating costs.

  • At lower RH levels, the pool evaporation rate increases dramatically. This increases both the dehumidification load and the pool water heating requirement.
  • In cold climate applications it is important to ensure no more outdoor air be introduced than what the codes require. More is not better in this case as it causes the RH levels can plummet to as low as 20, costing the operator in dearly in increased air and pool water heating costs.
  • Swimmers leaving the water feel chilly at lower relative humidity levels due to evaporation off their bodies
Figure 1 - Relative Humidity Impacts Occupant Health
Figure 1 - Relative Humidity Impacts Occupant Health

The type of facility being designed will typically dictate the space temperature. Table 1 helps target some typical conditions. It is critical to understand who will be using the facility in order to deliver the conditions most likely to satisfy them.

Typical Natatorium Design Conditions
Pool Type Air Temperature (°F) Water Temperature (°F)
Competition 75 to 85 76 to 82
Diving 80 to 85 84 to 88
Elderly Swimmers 84 to 85 85 to 90
Hotel 82 to 85 82 to 86
Physical Therapy 80 to 85 90 to 95
Recreational 82 to 85 80 to 85
Whirlpool/Spa 80 to 85 102 to 104
Table 1 - Natatorium Design Conditions

General Notes:

  • Facilities with warmer water temperatures tend to have warmer space temperatures.
  • Physical Therapy facilities will often cater to therapist comfort rather than the patient. The patient is generally not in the space for more than an hour, whereas the therapist is there all day. The designer should consult local codes. Some States require a full purge of the clinic room air with 100% outdoor air for every hour of occupancy.
  • Elderly swimmers tend to prefer much warmer air and water temperatures.
  • Maintain Relative Humidity between 50%& 60% RH. Do not go below 50.

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