Specifications

6
Natatorium DesigN maNual
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 seriously affecting the building structure or
result in complaints from the occupants. The designer
must take a complete system approach, from basic
engineering issues to the vital requirements of
air distribution. A complete understanding
of the design issues helps 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
the special temperature levels natatorium
patrons expect. 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 increased air and pool
water heating costs.
• Swimmers leaving the water will also feel chilly at
lower relative humidity levels due to evaporation off
their bodies.
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.
Comfort, Health and Safety
Figure 1 – Relative Humidity Impacts Occupant Health
Table 1 – Natatorium Design Conditions