Specifications

14
Natatorium DesigN maNual
Chlorine Smell
When you walk into an indoor pool and smell a strong
chlorine odor, you naturally think it’s caused by too
much chlorine in the water. The odor is actually caused
by chloramines (combined chlorines) off gassing from
the pool water surface.
Chloramines are formed in the pool water when there
is insufficient free chlorine in the pool to address the
nitrogen-containing compounds brought into the pool
water by the swimmers. These nitrogen compounds are
naturally-occurring and contained in sweat, urine, body
oils and other proteins that get released into the pool
water. If the introduction of these nitrogen compounds
outpaces the introduction of free chlorine, the chlorine
becomes combined with the nitrogen compounds rather
than fully oxidizing them.
The chloramine (combined chlorine) levels increase in
the water, resulting in an increase in chloramine off-
gassing, which creates the odor of chlorine in the room.
There are three different types of chloramines that can
form: monochloramine, dichloramine and trichloramine.
Trichloramine is the most volatile and will off-gas
most quickly.
The proper balance of chloramine control, air
distribution, outdoor air and room exhaust air along
with air movement at the water surface is also crucial
towards ensuring good indoor air quality.
Off-gassed chloramines have a strong attraction to the
airborne humidity and will combine with moisture in
the air. Consequently, any condensation of the space
humidity will become corrosive. An example of this can
sometimes be seen at pools with chloramines problems
where the ladder rails outside the water corrode while
the portion under water does not.
A very effective method of chloramine control is to
source capture them off the water surface and exhaust
them before they have a change become a problem.
Paddock’s Evacuator system was designed for exactly
this purpose and Seresco’s experience with facilities
using the Evacuator have been incredible successes.
Top notch air quality, even on retrofitted systems.
Ultraviolet light (UV) treatment of pool water has shown
to have a very positive impact on the water chemistry
and can help reduce, if not totally eliminate chloramines.
This approach to enhance water treatment is gaining
popularity and as positive data continues to come
should become more and more common.
Humidity and Corrosion
As previously mentioned, off-gassed chloramines
have a strong attraction to the airborne humidity and
will combine with moisture in the air. Consequently
any condensation of the space humidity will become
corrosive. It is critical that the space humidity levels be
controlled such that condensation is prevented as it will
damage the building and mechanical system.
By design, indoor pool environments are
warmer and as result have higher dew point
temperatures compared to traditional spaces.
Engineers and architects must understand the
consequences of moist corrosive air and and pay
special attention to its potential impact on the entire
HVAC system and building envelope.
Every Seresco unit has all electrical and refrigeration
components located in a separate mechanical vestibule,
protected from the pool air stream. All components in
contact with the pool air stream are protected with the
best possible corrosion resistant paints, coatings and
materials available. Seresco units are built to last!
Outdoor Ventilation Air
The amount of outdoor air to be introduced to the
facility is determined by local codes. Most codes adopt
ASHRAE Standard 62. Outdoor air is critical towards
diluting airborne chemicals and maintaining good indoor
air quality.
Facilities that introduce outdoor air per ASHRAE
Standard 62 and have proper air distribution have
outstanding IAQ.
• More outdoor air than required by ASHRAE Standard
62 is not recommended (except water parks)
• Outdoor air requires a significant amount of heating
energy in the winter and must be included in heat
load calculations.
• Heat recovery should be considered between the
exhaust air and outdoor air streams.
• Exceeding code amounts is not recommended,
as it creates extremely high operating expenses.
Engineers must ensure condensation is avoided.
Wintertime outdoor air is cold and in summer
it can be very humid. Both scenarios can lead
to condensation.
• Introduce the outdoor air at the factory provided
intakes on the
air handlers
• Locate outdoor air intakes away from sources of
airborne contamination such as exhaust fans or
plumbing vents.