Feature Article - November 2020
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Safer Swimming, Safer Breathing

Managing Water & Air Quality

By Joe Bush


Pearce said management encompasses a combination of things. The most successful pools with the best air quality have a plan laid out for how to manage their pool properly—keeping free chlorine controlled so there aren't huge spikes of free chlorine that cause additional chloramines, adding a secondary disinfectant like UV or ozone, and a successful turnover or dilution protocol in place that turns over water and turns over air to allow that chemical makeup to continue to happen.

"It's very difficult to get rid of something without getting rid of what you need," said Pearce. "You want to get rid of the chloramine, but you don't want to get rid of the chlorine and it's difficult to do successfully."

Pearce said budgets for hardware and software are obviously a limiting factor for facilities, but were they not, he recommends:

>> On-site chlorine generation. "It is the best by far because you're not introducing any byproducts into the water, you're just making simple elemental chlorine and there's nothing else for the reaction to occur," Pearce said.

>> Adding ultraviolet light. "It is the most efficient way of reducing chloramines," Pearce said. "Add an ORP/PPM /pH control system to marry all those technologies together to control the free chlorine in the water at the optimum level as consistent as possible all the time."

>> Air handling unit with ability to adjust based on number of bathers—more bathers, more turnover and vice versa.

>> Controllers that can handle all of it. "They can control the chlorine, the pH to make sure the chlorine is as active as possible, and the air handling units to make sure the air switchover is optimal for when there's the most bathers," said Pearce. "If you marry all those together you have by far the best system possible. Unfortunately it doesn't come cheap."

The most common issues facilities are trying to fix include upgrading systems, said Pearce. The majority are looking to be more efficient, getting into the 21st century in how to control water while saving energy.

"It's difficult to control (water) when you have chemicals on site and you have a 16-year-old lifeguard taking care of things," said Pearce. "The chances of issues are high, and a lot of (facilities) look at changing (systems) just for that reason."

Pearce said the expense can be handled with lease plans; water and air safety should not suffer because of funding.

"Water and air quality are very important," said Pearce. "It's really important especially in places like swim schools, which are very much affected by air quality because you have all those instructors in the water eight to 10 hours a day breathing that air in all the time, and you have the kiddos with young lungs breathing it in. It's essential they have their air quality controlled properly.

"A big Great Wolf type waterpark is important but not as important as a swim school where you've got 1-year-olds learning to swim. Our equipment is in a lot of swim schools across the country—adding the UV in order to control the chloramines is a big deal, and they all do it because they're very concerned about the air quality."

Carl Nylander, a principal at Counsilman-Hunsaker, said when the Model Aquatic Health Code (MAHC) was initially developed, the ventilation and indoor air quality technical committee recognized that current ASHRAE baseline recommendations were insufficient for many aquatic facility types.

He said ASHRAE calls for a minimum amount of air (0.48 CFM/SF) based on the overall pool size. However, the standard doesn't address the volume of the natatorium space, which can vary tremendously depending on the facility type and function. Additionally, ASHRAE acknowledges the additional moisture load from other pool types beyond traditional lap pools. But these "activity factors" can be generic and don't address all situations for designers.

Nylander said the air quality recommendation portion of the MAHC is a current focus.

"It was acknowledged that additional research and data was needed before bringing these recommendations into the body of the code," said Nylander. "An ad hoc committee of industry experts has been convened during the current Council for the MAHC cycle to further analyze the data, with the goal of reaching a consensus to propose air system design requirements that are not just based on the air delivery rate but also the bather load, amount of fresh air, types of aquatic amenities, and distribution of air within the natatorium." RM