Tuesday, June 26, 2012

Swimming Pool Water Chemistry Expert Automation Chlorine Bleach Storage

Swimming pool water chemistry automation expert witness discusses the proper storage and metering of liquid chlorine bleach (sodium hypochlorite - NaOCL).

Proper Containment
Liquid bleach should be stored in a cool location out of the direct sunlight.  UV, heat and direct sunlight will degrade the bleach.  It will however stop degrading once it reaches a concentration of 5%.  The UV will also degrade the storage container, rendering the plastic brittle & prone to leaking.


Additionally, the heat will cause the bleach to off-gas, forming bubbles within the dispensing tubing.  Minimizing the length of tubing will reduce the formation of gas within the tubing.


Whenever large quantities of bleach (or acid) are stored, they must be contained within a secondary vessel.  This outer containment tank must be 110-120% of the capacity of the inner barrel.  The minimum quantity (gallons) and concentration of chemicals (%) stored on a site that will trigger the requirement for the secondary containment will be determined by the local authorities (usually the fire department or fire marshal).  


Dilution
Oftentimes a facility will have metering pumps that are sized incorrectly.  Instead of purchasing the correct equipment, maintenance staff attempt to "fine tune" the metering or dosing of the chlorine by diluting it with water.


However, this causes a myriad of problems that only serve to increase the required labor and maintenance cost, costing more in the long run than purchasing the correct equipment.


The high pH of the bleach causes the minerals in the water to precipitate out of solution.  These minerals and salts clog the metering pump, foot valve, tubing and solidify at the injection point.  This requires more frequent cleaning of these components with an acid solution.  Mixing acid with the bleach forms a dangerous chlorine gas (WWII = Mustard Gas).  This frequent and unnecessary exposure to hazardous chemicals and gasses can be avoided by merely using one's brain!


Salts Formation
It is virtually impossible to prevent the formation of salts at the point of injection into the pool plumbing.  The minerals inherent in the pool water will also precipitate out of solution at this point of contact.  Over time these salts will eventually clog the injector.


The solution to this is to install the acid injector in the line prior to the bleach injector.  The acid solution passing by the bleach injector will automatically clean the bleach injector.  The time required for build up of injector clogging salts will be lengthened exponentially.


Automation
Anyone who designs, specifies or builds commercial swimming pools, spas or aquatic facilities is a fool if they do not specify automation of the water chemistry.


Though they cost approximately $4,000 to install per vessel, the resulting operating costs are significantly reduced.  The water chemistry is constantly balanced, eliminating spikes in the chemicals from manually adjusting and dosing the water.  Manually dosing or adjusting the water causes unnecessary wear on the plaster, equipment and plumbing.


The automation is watching the water chemistry 24/7.  In an athletic club spa, this means it will automatically respond to the influx of bathers after an aerobics or gym class.  The water will not smell of "chlorine" - which is actually the off-gassing of bather waste that has turned into gaseous ammonia compounds called "chloramines."  That "chlorine" smell really means that there is not enough chlorine in the water!


The ever vigilant automation system prevents over dosing of chemicals if the facility is not used as heavily as was forecasted.  Conversely, if the facility has a sudden and unexpected influx of bathers, the chemicals are not overwhelmed and the pool or spa does not turn yellow or brown.

The cost of automation is within reach of even the smallest apartment or condo complex.  The cost - benefit analysis makes sense, the finishes and support equipment lasts longer, bather complaints are eliminated and reoccurring maintenance costs are reduced.


Water chemistry automation - it's a no brainer!

Paolo Benedetti - Aquatic Artist, Consultant & Construction Defect Expert Witness 
"Creating water as art."™ 
Aquatic Technology Pool and Spa 
©www.aquatictechnology.com

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If you want to ask a question of Paolo Benedetti, you may email him at: info@aquatictechnology.com