Think of all the rooms you have been inside. Offices, classrooms, restaurants, your bedroom, etc.. Every indoor room probably had a ventilation system of some sort, and that system was designed by a Professional Engineer (P.E.). Specifically, a mechanical engineer. Now ask yourself: how many of those rooms contained an indoor swimming pool?
Indoor swimming pools (aka natatoriums) are few and far between. This means that most engineers will never work on one. It also means that those few engineers who do work on natatoriums typically will not have many to design–at least, relative to the number of other rooms they are designing without pools. Natatorium design is a niche.
In other words, most natatorium air quality problems are [in part] because there are so few natatoriums in the first place. Few natatoriums means less chances (and less need) for engineers to learn and understand them. And because natatoriums are so rare, learning from their air problems is also rare.
Most engineers do not receive a phone call about a pool having problems until it is many years later. By that time, any number of things could be impacting the air quality, so the clear line of responsiblity becomes blurred. Let's face it...designing an indoor pool HVAC system is challenging and risky.
The Engineer's Dilemma
Is it reasonable to expect perfection the first time doing something? No way! Ask any parent about how they raised their first child compared to the others. Or ask an entrepreneur if their current company was the first one they worked for. We grow by doing and failing, learning from the failure, and trying again. Practice, practice, practice.
So why expect a mechanical engineer to nail a natatorium design on their first attempt? It's unfair to the engineer. Nevertheless, the health consequences of a flawed natatorium design are very real to those of us who swim and spend time in indoor pools. And therein lies the dilemma.
We swimmers must rely on the engineer to design an air system that covers many variables that do not exist in any other type of room...while also designing for healthy indoor air...and their guidebook, ASHRAE 62.1, has a natatorium section only four pages long. That's unreasonable, and it is a recipe for failure. So while air quality problems may not be entirely an engineer's fault, often it is their responsibility anyway. To make matters worse, air design is often the only thing that can fix the problem. That's quite a dilemma indeed.
The Blame Game
Historically, water and air people point fingers at each other when air problems occur. "Fix your water chemistry!" "My chemistry is balanced, fix your air handler!" Back and forth the fingers point. Meanwhile, swimmers are coughing and their doctors are prescribing albuterol inhalers. We know from personal experience.
And while the swimming pool and wet deck are the primary sources of chloramine pollution, there is very little on the water side that can be done to stop the problem. This is necessary, inevitable chemistry that must be dealt with on the air side.
Even with secondary systems like UV and Ozone, air quality problems persist (despite what manufacturers believe and claim). Most customers of ours that had bad air quality problems already had UV or ozone. Yet the airborne chloramine problem was as vicious as ever.Timing must be taken into account. Sure, Ultra-Violet (UV) sanitization systems destroy waterborne mono- and di-chloramines. But like Ozone, UV is a point-of-contact system, at the mercy of the circulation rate of the pool. In other words, it can only affect the water that passes through its chamber. And monochloramine is produced in seconds, not hours.
Fixing water helps, but does not solve
Even with optimal water quality systems, chlorine will still combine oxidize nitrogen compounds and bather waste. Chlorine will still combine with ammonia and create disinfection byproducts (DBPs). And because these reactions happen so fast, eventually these byproducts will go airborne, and at that point, UV or Ozone cannot touch them anymore. The pollution is now an air problem entirely.
We know this from experience. Most of the pools we have visited had UV or Ozone already installed for years. Their natatorium HVAC systems were also designed within ASHRAE 62.1 standards. And yet they all had air quality problems. We could talk about this knowledge gap for days, but let's summarize instead.
Consider the extraordinary variables a natatorium has that no other type of room does. Moisture loads, changing evaporation rates (depending on air and water temperatures), temperature deltas that lead to extreme energy costs, vapor pressure, strict temperature target (2ºF above water temperature), strict RH % target, and of course, corrosive airborne contaminants like chloramines. There are more, but you hopefully get the idea. Natatoriums are not like other rooms.
As mentioned before, an engineer is likely to be blamed for air quality problems, but sometimes that is unfair to the engineer. Natatoriums are notoriously difficult to design, and there are so few of them to learn from. Compound that fact with the design standard 62.1 from ASHRAE having just 4 pages in its handbook devoted to Natatoriums. And on top of that, those 4 pages are wide open to interpretation, because we have seen hundreds of natatoriums designed within the standard that had bad air quality problems.
Futhermore, without consulting with the pool operators themselves, an engineer will not know how a pool is going to be used. All it takes is a miscommunication (or lack of communication) between the pool people and the air people, and problems can occur. For instance, what if the operators crank up the water temperature to make the seniors and children happier? Now the evaporation rate has changed, which changes other factors that stress the dehumidifier, etc., etc..
For decades, design professionals have missed the crux of the problem, and it has not necessarily been their fault. But it has been their responsibility. While they were trying to do the right thing, when problems arise, engineers are often the only people who can help. The aquatics staff can only do so much. As we said earlier, that burden is quite a dilemma for an engineer.
And that's where we come in. We help engineers design natatoriums with all the factors and consequences in mind.