The Air in There
Managing Air Quality in Aquatic Facilities
There's an old aquatics industry joke:
How do you ruin a pool?
Put people in it!
All comedy has some truth in it, and there's no doubt that the chemicals used to disinfect pool water are just fine if left alone. But pools are for use by humans, and when they get in, they bring organic material that activates the chlorine to do its work. When it does that job, it changes to chloramines, which produce the smell commonly associated with pools.
Those chloramines are not good for eyes or lungs, and need to be regulated with additional doses of chemicals to the water and the circulation and exchange of the air that the chloramines escape to. Outdoor pools need only manage the water chemistry to ensure swimmer safety, but indoor safety includes air management.
Today's state-of-the-art aquatic operations feature systems that include communication between water and air handling to not only improve water and air safety but also save energy. However, budget-conscious facilities don't necessarily need state-of-the-art equipment to maximize air and water safety.
In 2014, the Centers for Disease Control and Prevention (CDC) issued the Model Aquatic Health Code (MAHC) to guide government agencies and aquatic professionals in their pursuit of public health. The MAHC covers design and construction, including secondary disinfection systems to kill chlorine-tolerant germs, and policies and management, like training for pool operators to reduce pool chemical injuries, pool closures and other issues.
The MAHC fact sheet reveals the seriousness of unsafe water:
>> Nearly 500 disease outbreaks linked to pools, hot tubs/spas and water playgrounds occurred from 2000 to 2014. The leading cause of these outbreaks is Cryptosporidium. This parasite is chlorine-tolerant and can cause outbreaks that sicken thousands.
>> A recent study found that one out of eight (11.8%) public pool inspections and one out of seven (15.1%) public hot tub/spa inspections resulted in immediate closure because of at least one identified violation that represented a serious threat to public health.
>> Sampling of public pool filter water found that more than half of samples contained Pseudomonas aeruginosa and E. coli or feces. Another study found one out of 12 pool filter water samples contained the parasites Cryptosporidium, Giardia or both.
The MAHC doesn't address air safety, but its council announced last March that the MAHC's Indoor Aquatic Facility Ventilation Design and Air Quality Ad Hoc Committee is partnering with Purdue University and Michigan State University to conduct a study to determine the operating conditions for indoor pools to help prevent the buildup of chloramines in the air.
The study aims to identify what design and operational issues affect air quality and climate control, and its results will be used to update the MAHC's design and operational guidelines.
Jason Schallock, chief operating officer of Anderson Poolworks, a designer and builder of commercial pools, is on that ad hoc committee and said its most recent work is exploring the relationship between water and air quality.
"We are learning more about events that spark chloramine formation and release into the air," said Schallock. "Advancements in ventilation like source capture systems help on the air side by removing airborne chloramines at the source. Better water chemistry control systems in combination with ultraviolet systems are being used to reduce combined chlorine in the water."
It's clear that just as pool water is fine until there are swimmers in it, facility air is fine until chloramines are produced. To manage both, Schallock recommended that facility operators should: maintain equipment and make sure that all systems are operating correctly; create easy-to-follow rules for users and staff that promote healthy use and care of the pool; and do not short-change dehumidification, air handling or water quality systems.
"We see a lot of these systems either 'value engineered' out of projects completely or cut down to lower quality for aesthetic components on or in the building," he said.
The push for better air quality is more recent than developments in water quality management with chemicals, which has its roots in the early 1900s. According to George Bailey, vice president of sales and marketing for a South Carolina-based manufacturer of instruments and chemistries for testing water parameters, testing the water is imperative to better management and safety, and it has evolved in the past 50 years from test strips to the improvement of those strips to the use of photometry and linking to mobile device applications.
Bailey said the MAHC has illustrated the need for water test kits that have been certified to perform to standards of accuracy, reproducibility and repeatability. Certified test kits are given a rating of Level 1, 2 or 3, with Level 1 being the most accurate. Operators should keep some water testing basics in mind, Bailey said.
"When testing with a certified water test kit, it is important to follow each manufacturer's test instructions to the letter since they may differ from similar test kits," he said. "Always use fresh reagents or strips that have been stored in a cool dry area away from chemicals. Heat and moisture are their worst enemy because they will drastically shorten shelf life. Only use test kits specifically designed for pool and spa use."
Mike Fowler, commercial sales manager for a Minnesota-based water treatment company, said there are "do" and "don't" basics for aquatic facility operators to consider:
>> Do add UV or ozone to a system to achieve greater success in elimination of chloramines and provide a better swimming experience for members or guests.
>> Do not think automated chemical controllers or systems are "install and walk away." Inspect the systems periodically and properly maintain them to make sure they're doing their jobs.
>> Do not let a small issue with equipment or chemical balance turn into a larger problem that may result in pool closures.
Richard LaMotte, vice president of sales and marketing for a Maryland-based water analysis company, added a few fundamentals of his own:
>> Never let pool operators skip testing critical test factors and rely solely on automation.
>> Online automation is helpful, but even a small power outage has led to hazardous water conditions in the past.
>> Always use DPD to test free and total chlorine to determine chloramine issues—virtually all U.S. states require this methodology.
>> Make sure all pool operators are tested for color-blindness or are using a colorimeter rather than analyzing water by guessing at colors.
>> Check expiration dates every month on your test reagents.
>> Make sure ventilation levels meet or exceed local code requirements.
>> Find ways to encourage swimmers to shower before entering.
"Many of the chloramine compounds that lead to odors and irritation could be reduced by quick showers prior to entry," LaMotte explained.
Of course, not all aquatic facilities are created and used equally, said Kevin Post, a principal at aquatics facility consulting and design firm Counsilman-Hunsaker. Waterparks have shallower water and more kids, and more kids means more likelihood of urine and feces. There are jets and sprays and agitators as well, so it's an environment in which chloramines are created rapidly and are thrown into the air.
In lap pools, the water's calmer, users aren't breaking the surface as much, there's no spraying water, and swimmers are primarily adults. Chloramines don't form as quickly, nor are those formed being agitated.
"So it's really a demand balance," Post said. "All have a different requirement for pool water treatment as well as the air treatment."
Post said all use the same basics—chlorine in the water and some sort of pH buffer like a CO2 or acid to keep that pH within health code ranges. He said the MAHC has recommendations for secondary disinfection and secondary sanitation.
"For what (the MAHC) considers high-risk pools like wading pools with a high risk of crypto outbreak because of diapers, and therapy pools, it wants UV added," he said. "UV also helps destruct the chloramines, it will kill the viruses and protozoa like crypto, but it also destructs chloramines. For indoor waterparks, you're going to put UV in every body of water. For an indoor university pool, it would help but you can get away without it."
The amount of water per bather matters as well, said Post. If you put 50 kids in a pool with 50 gallons, that's only 1 gallon per kid. If you have 10 high school lap swimmers in a million-gallon Olympic pool, that's 100,000 gallons per person.
"If you're diluting everything greater you don't need to treat it as quickly," said Post.
Brett Steinbrueck, president of a Missouri-based water chemistry controller company, said chlorine and pH are the essential factors that need to be monitored and managed. If pH levels aren't right, the chlorine is not as effective, but today's facilities need much more than managing that most basic of calculations.
State-of-the-art chemistry control systems are wireless, programmable in many ways and can also handle alkalinity levels and the addition of ultraviolet germicidal irradiation disinfection.
"Some UV systems are installed and run full blast," Steinbrueck said. "We have systems that can monitor the combined chlorine and ramp up the UV system when there is higher combined chlorine and down when there isn't so much."
Steinbrueck said operators have to be cautious when considering controller systems; know the expected bather load on the body of water before shopping. Ask suppliers to audit the facility and program's needs and make recommendations, Steinbrueck said. How many swimmers there are and what type of swimmers is crucial.
"It's about load and how it's used," he said. "Generally speaking, you're looking at the surface area that's exposed and the bather load and type of bather load. The heavier the bather load, the more organics, the more chlorination, the more chloramines. The controllers are responsive enough to demand. It's more a matter of understanding the load you expect to see and having feeders that can deliver the load of chemicals fast enough."
The next step is to marry the water controllers with the air-handling systems, said Steinbrueck, and that is happening. That process begins with the installations of each system, or both, depending on whether the situation is new construction or a renovation.
"Generally speaking, the air-handling people don't know that much about pools, so they really do need some support to make this work," Steinbrueck said. "When you look at it as a whole system instead of as a pool or as air, you end up with a really nice opportunity for improvement."
Potential issues with air quality begin with water quality. When chlorine is turned to chloramines—combined chlorines—there's volatility that leads to escape from the water surface. The gas sits just above the water and is inhaled by the pool users, then rises to be inhaled by people on the deck—lifeguards, parents, coaches and spectators.
When people who are not in the water begin complaining about irritated eyes and difficulty breathing, something needs to happen to the air. The answer is circulation and exchange, the job of the HVAC system. Fresh air is brought in from outside, replacing the old air.
How much outside air is brought in and how fast are the calculations needed to maximize air quality. Also at issue for facilities in winter climates is the heating of the air brought in.
Tom Carrico was a swimming coach at the youth, high school and college levels before starting Carrico Aquatics, a company that helps facilities with water quality, operations and maintenance activities, equipment status, operation cost, preventive maintenance and budgetary considerations.
He's seen lifeguards with lifeguard lung from breathing chloramine-filled air, and coached kids who developed asthma from hours at and in pools. Carrico said his company attacks unsafe water and air comprehensively.
"We'll put in a chlorination system, we'll put in UV, and then we use a controller with a variable frequency drive," said Carrico. "The system tests combined chlorine, and if the combined chlorine starts to increase, it will send a signal to the air handler that tells the air handler to start exchanging the air.
"If we speed the exhaust fan up, it'll cause the supply fan to bring more air into the room. As our water starts to get dirty, we start exchanging the air in the room. As the air gets cleaned, we can slow that down and use the same air over again so what we're doing is maximizing the oxidation rate in the pool water, killing off everything we can, and what we can't kill we measure and tell the air handler it needs to exhaust the air in the room.
"What has happened is, we've eliminated chloramines in indoor pools, but the second thing that happened that we were not expecting to happen is we have reduced energy costs by up to 40 percent."
The energy savings happens when less is spent moving air when the pool is in less frequent use and less heat is used to warm cold air brought inside in the cooler months, Carrico said. This system can be enhanced with air exchange that sucks the old air from the room at the pool level rather than higher up, said Carrico.
Don Baker is CEO at a South Carolina-based company that manufactures a system specifically designed to pull air from the pool surface and send it out of the building. After a Greenville, S.C., pool was condemned for the corrosive structural damage caused by chloramine-filled air, one of the pool's volunteer coaches, himself an engineer, decided to approach the problem differently. Instead of protecting structures from the air, he sought to remove the air.
The resulting product can be placed on the deck or in poolside gutters or in walls and works with a facility's dehumidification system.
"If chloramines can destroy metals, what are they doing to our kids?" asked Baker, who is on the same MAHC indoor air committee as Schallock. "Poor indoor air quality for pools is as significant as concussions are for football. I will not let my grandkid swim indoors unless the pool is operated properly and they have a well-designed and operated air handling system." RM
In Practice: University of North Texas
Chris Lawrence has firsthand knowledge on managing the relationship of water with air in aquatic facilities.
Lawrence is associate director of facilities at the 16-year-old Pohl Rec Center on the campus of the University of North Texas. The center has a 25-yard lap pool, shared with the UNT swim team, and an indoor leisure pool with a spa. Each enclosure has its own dehumidification system to control the heating and air conditioning.
Lawrence said the lap pool has had air quality issues, but only after the center had been open a few years. Complaints from athletes started coming in periodically, leading to air quality tests.
"They were looking specifically for chloramines," said Lawrence. "The tests indicated a slightly elevated amount, but nothing very substantial. It was determined at the time that it was not a significant enough problem to warrant a large expense."
The center added UV lamps as a secondary water treatment, and placed large fans aiming air up at the air returns and blowing across the deck which were used primarily during athletes' training times. Management's hope that this would help with what it saw as a minor issue was eroded by more and more complaints.
"Again, it was only the athletes that were experiencing any issue; however, this makes sense since they were the ones spending the longest amount of time in the pool and were in the water with the largest volume of swimmers exerting themselves," Lawrence said.
The UNT environmental safety office conducted a second air quality study, and it showed more significant chloramines present at peak athletics usage time. The school asked an aquatics facility consulting firm for an assessment, and it found that the location of the return on the HVAC to the dehumidification system was not ideal for pulling the chloramines, which sink and stay just at or above water level. The return on the HVAC was about 20 feet above the pool deck.
UNT had several choices, from refitting its air handling system to simply installing a fan over the lap pool.
The idea behind the fan was simple, said Lawrence: The chloramines create a bubble at the pool surface level, and the downward force of the air would, in theory, break the bubble forcing the air to the sides and back up, and hopefully to the HVAC.
"We opted for the fan, and had it installed a little over two years ago," he said. "Since its installation we have not had complaints about the air quality."
Lawrence said the problem and solution has taught him several things about aquatic water and air quality, but two stand out:
>> The type of usage a pool will have is crucial in the design phase. Once pool systems are installed and things are built out, there are no easy or cheap solutions.
>> The effects of bather loads.
A recreational lap swimmer at the Pohl Center spends an average of about 15 to 20 minutes in the pool. In busy times there is a load level of six to eight swimmers.
"It is quite a bit different for the swim team, which has 30 athletes going for two hours straight at a time and even more during meets," Lawrence said. "The impact on the air quality is significant between the two groups."
Lawrence is in a position to help others who have the same duties. Be prepared to spend a lot of time working through various challenges because despite the best planning, there will be hiccups, he said.
Operators should get to know the intricacies of their pools, said Lawrence—the usage type, user loads, the equipment like HVAC, water treatment chemical feeders and chemical monitoring systems.
"They all play a role in the end experience for the user," Lawrence said. "Each aquatics environment is unique and presents a unique challenge in producing a positive experience for the user."