ASHRAE 1999 HVAC APPLICATIONS MANUAL STATES: “ Humans
are very sensitive to relative humidity. Fluctuations
in relative humidity outside the 40-60%
range can increase levels of humidity,
bacteria, viruses, fungi and other factors
that reduce air quality. For swimmers,
50-60% RH is most comfortable. High relative
humidity levels are destructive to all
building components. Mold and mildew can
attack walls, floor, and ceiling coverings;
and condensation can degrade many building
materials. In the worst case, the roof
could collapse due to corrosion from water
condensing on the structure.”
The
term “Relative Humidity” expresses
the moisture content of the air as
a percent of what this same air could
hold if it was completely saturated.
The
ability of air to hold moisture increases
with a rise in temperature and decreases
with a lowering of the air temperature. If
you cool a volume of air sufficiently
it will reach a point the amount
of moisture it can hold is equivalent
to the amount of moisture that it
actually contains. This is the point
at which the air is saturated or
is at 100% Relative Humidity. If
you then increase the temperature
of this air to a point where it can
hold twice as much moisture as it
actually contains, it is now at 50%
Relative Humidity.
RELATIVE
HUMIDITY within a pool room is maintained
higher than your home or office. ASHRAE
recommends the RH to be set between
50-60% Relative Humidity. Lower than
50% and higher than 60% is not recommended
because of increased humidity levels.
Lowering the humidistat setting to
under 50%RH also increases the evaporation
rate of the pool water. This is not
recommended and may cause problems
with the building.
EPS is the home of DRY-AIR & VERI-DRY. We provide Design, Engineering, Consulting and Manufacturing for Residential and Commercial Indoor Swimming Pool Applications.
