When it comes to some indoor pools, it’s time to clear the air.  What the staff, swimmers (many of whom are children), their parents and others visiting the facility are breathing is a big deal, but do you understand just how much of a big deal it is?  Keep reading to find out.

 Ever walk into the pool and smell the Chorine before you see the water?  What you think is the normal “pool smell” is really not.  What you are really smelling is the byproduct of ‘Free available Chlorine’ doing exactly what we need it to do, get rid of nasty stuff in the water. That byproduct comes in 3 different varieties:




 The first two, mono and dichloramine, stay in the water and are what is referred to as ‘Combined Chlorine’, you know, the stuff you monitor and shock when it gets too high.

 The third one, trichloramine however, leaves the pool water and of-gasses into the air. These off-gassed trichloramines are what you are smelling. Apart from just smelling bad, they are accompanied by the following effects:

     Breathing issues

     Skin and eye irritation

     Corrosion of metal fittings, futures and deck equipment

     Destruction of mechanical systems and ductwork

     Degradation of structural support systems and building materials

 So, what does that mean?

 It means that people exposed to heavy chloramines can develop breathing issues including COPD, and permanent lung damage. Mass hospitalization has, and continues to occur when chloramines get out of control. 

 It means that maintenance cost is significantly increased to keep corrosion off of deck equipment, repainting and replacing or repairing other metal fixtures throughout the building.

 It means that dehumidification systems (one of the most expensive systems in your building), air ducts, registers, fans, belts, motors, and more are actively being destroyed much quicker than normal wear and tear.

 It means buildings are more prone to high end structural repair needs, taking large amounts of funds away from program development and facility growth.

 Natatorium design has come a long way, but the same mistakes are made over and over again.  Hang on, we have good news, there is a solution and it can be accomplished on new and existing indoor pools alike thanks to one thing; we know where these pesky chloramines are.

 Chloramines are about 4-5 times heavier than air. So, guess where they like to hang out? Right on the pool surface.

 What’s the solution you ask?

 When designing (or re-designing) the air handling system for a natatorium (room with a pool in it), we want to keep a few things in mind:

     Get fresh air into the breathing zone(s)

     Don’t DE stratify the air

     Use a low source capture system

     Keep chloramines away from the return air vents

 Let’s answer some questions that may have just popped into your head.

 What is a breathing zone?  An area where people’s mouths are situated by design of the building. This typically includes:

     Just above the pool water

     Midway up on the deck

     In any spectator areas

 What do you mean, don’t DE stratify the air? Don’t mix it, keep it layered. Keep the bad air low, and the good air high.

 What is a low source capture system? It is an exhaust only system that drags air from a specific place, (in this case, where Chloramines are hanging out) and removes them from the building, never to be seen again. Low source capture can be placed in the gutter, the deck drain, or in a pre-fabricated bench or wall systems. Remember when we said that these gasses like to hang out just above the pool water? This exhaust system removes the bottom layer of bad air, while keeping the good, heated and treated air inside and recirculated as intended.

 Why keep chloramines away from the air returns? If those chloramines get into the returns, guess where else they end up?  Coming out of the air supply… RIGHT INTO THE BREATHING ZONE! Where swimmers, spectators, and staff are.

 Think of it as a slice of pie. We want to remove the crust, while preserving the filling. And we want to keep any crumbs of the crust away from the spoon used to add more filling to the pie. The crust is the chloramine laden air, the filling is the good, reusable heated and treated air, and the spoon is the return. Think of a low source capture system as a knife that separates the two and does only that.

 Let’s be honest, saying that smelly pools are okay, is not okay.  At Paddock Pool Equipment Company, we have spent the last 12 years working on improving the quality of air inside of natatoriums and have provided clean air solutions for over 500 facilities. We do this with a product called the Evacuator®.  It is in our, and many others’ genuine opinion that any pool built inside of a building, needs Evacuator® technology.

 Good indoor air quality is fundamental to the health, safety and enjoyment of those working, training or playing in your facility, and is essential to maintaining the look and functionality of the building itself.  If your pool smells, let’s clear the air.

 To learn more, check out paddockindustries.com or call 800-849-2729.


 Andrew Roberts & Mark Hines


Paddock Pool Equipment Company