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Las Vegas Adult Community.

Good Morning,

The Model Aquatic Health Code (MAHC) has released the draft module of the Ventilation Code Section for the first 60 day review. Ending on June 12, 2011.

In the June 2011 issue of Aquatics International is an article by Franceen Gonzales, chair of the Model Aquatic Health Code Ventilation Technical Committee.

In the very early beginning she writes and I quote " So if you have a lot of chlorine in the water as well as a lot of urine and sweat, then you are going to have combined chlorine, the precursor to TCA" TCA stands for tri-chloramine, the most aggressive of the chloramines found in the indoor swimming pools.

It is interesting to find that the Ventilation Technical Committee choose the way, in the interest of the health of the people inside the indoor swimming pool, to dilute the amount of tri-chloramines instead of focusing on the removal. Because, if the previous quoted statement is correct, and it is, then it must be also correct that if you have no chlorine in your pool, the tri-chloramines can not form. And that would be the end of the story.

Now I realize that leaving the chlorine out of the pool water causes other issues and I fully agree with the committee that these issues have not been resolved yet. Chlorine is still needed ( and often required by law ) in the pool water to disinfect the water. However there are solutions like UV light and Ozone treatment that can greatly reduce the amount of chlorine in the pool water and thus greatly reduce the amount of tri-chloramines.

Hiding behind the health concerns of the bather and without any regard to the effectiveness and efficiency the committee dramatically increased the requirements of outside air. This does not address the problem. The problem is the chlorine in the water combined with the fact that swimmers do not want to take a shower before they go in the pool water and that in many cases the staff is not trained or equipped to keep the right chemical balance in the pool water.

In the draft module the MAHC Ventilation Technical Committee suggest a dramatic increase in the use of outside air and does so in a confusing manner. For instance Table 1 shows Ro (CFM Outside Air per Occupant) values for flat water(10 CFM), agitated water(25 CFM) and hot water(60 CFM) but does not indicate if these values need to be combined, as in Flat Hot water 70 CFM (10+60) or hot agitated water 85 CFM (25+60).

Simple calculations also show that the increase in required heating capacity when the suggested outside air requirements are followed is well above 300% in other words, operational expenses, already huge for indoor swimming pools because of all the heating, air moving and pumping requirements, will increase dramatically.

Another interesting aspect of the draft proposal is the fact that it now introduces OSA in accordance with ASHRAE when the pool is NOT occupied. The factor Ra in table 1 reflects the outside air requirements as suggested by ASHRAE for occupied use of the indoor pool, however in the draft proposal the Ra factor is defined as CFM/Ft2 required for area without occupants. This means that also the night time operational expenses, when the pool is not used and minimal production of chloramines takes place, dramatically will increase.

It almost appears that the Ventilation Committee, in its eager to make sure that nobody will ever have an air quality issue with the indoor pool air, has gone way overboard with regards to the use of outside air. It would have been better if they had investigated new technologies to address the actual problem, minimizing the use of chlorine. Going in that direction would have helped both the industry, allowing for new and different designs, and the owner in keeping the operational cost down. The committee has chosen to go the path of least resistance. Increase outside air at low first cost and pay during the operation of the pool for many, many years to come.

If the indoor swimming pool environment is of concern to you can link to the comments section of the MAHC Ventilation Draft through aquaticsintl.com

Enjoy the day.

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