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Improving Indoor Air Quality for Pools

A client recently approached Efficiency Engineering (EE) to review the HVAC system serving a pool and adjacent community center spaces for an apartment complex. The building has experienced a prolonged period of uncontrollable indoor air conditions and poor air quality in and around the basement pool and adjacent corridors and recreation spaces. The recreation centre areas have reported high air temperature and humidity and significant pool chemical odours observed far away from the pool and change rooms. These two factors were indicating pool air was mixing with corridor ventilation.

A site evaluation showed the existing systems are aged, and likely contributing to the observations. They appeared to lack the key features modern pool systems are designed to control pool temperature and humidity, preserving indoor air quality and minimizing energy consumption it was a perfect opportunity to bring this building up to modern standards.

Modern pools are designed to be enclosed with dedicated dehumidification systems to perform many key functions:

  • Minimize the pool water evaporation rate; Maintain sufficiently high temperature relative humidity to regulate/minimize evaporation rate, a great source of energy loss and water consumption
  • Ensure sufficient flow or warm air over exterior windows to ensure condensation does not occur on exterior surfaces, especially windows.
  • Mitigate pool chemical leaden air from escaping into the surrounding areas resulting in undesirable odours, accelerated building degradation and corrosion, occupant discomfort

The factors governing the design of a pool ventilation system are diverse and interconnected. A change in one parameter, such as pool water temperature, can have a drastic effect in how much dehumidification will be required.

Unlike modern pools that are partitioned enclosed and have a dedicated ventilation system to control both ventilation (fresh air) and humidity, this building has no real control of fresh air, temperature or humidity. While contained in its own building separate from the apartment complex and having a dedicated heating and ventilating unit, it shared a common corridor at the basement level with the apartment buildings. As a result there is no physical separation of the pool and resident spaces. This results in the moist, chemical laden air migrating to the entire lower basement level due to the separate corridor exhaust air systems drawing pool air away via the corridor.

EE has the experience to identify several ways of correcting the existing design and bringing it up to modern design. Wanting to minimize impact on the existing infrastructure, we proposed to re-purpose and reuse the existing supply ductwork and replace the original heating and ventilation unit that has reached the end of its useful life.

Secondly and most importantly, a properly sized dedicated dehumidification unit will be installed. The unit will serve to maintain the humidity levels in the pool. While a small amount of new ductwork will be required, this is be preferred to gutting and re-doing all of the existing supply ductwork that is buried beneath the floor slab. The dehumidification unit shall include a integral exhaust fan to maintain negative pressurization of the pool and eliminate chemicals and odours from escaping into the building.

Lastly, a partition wall shall be constructed to physically separate the pool from the basement corridor. These three measures, when combined, will ensure a more comfortable pool and building environment.

Natatoria are energy intensive installations that require careful planning and particular care needs to be taken to ensure proper performance and user comfort. Efficiency Engineering is well suited to conduct engineering reviews and assessments of your natatorium and ventilation systems.