COMMERCIAL POOLS IN SUMMER
Summer Pool Plant Tips Robbie Phillips and Richard Lamburn, STA’s Technical Pool Plant Team, look at two conditions that will be faced by many commercial pool operators this summer
ith the summer now in full swing, schools, colleges and universities will be closed down for the summer break and usage of swimming pools will hit annual highs. In this issue of SPN we will look at two of the challenging conditions that result from the summer sun and increased participation; this includes a close look at temperatures both inside and outside of the pool water plus the sun’s impact on the effectiveness and use of disinfectants.
POOL TEMPERATURE One of the most important elements to a swimming pool user is temperature. However, the varying demands of bathers often make it nearly impossible to provide a temperature that is satisfactory to all pools users. For example, gala competitions will require temperatures to be between 25-28°C, while recommendations for babies and younger children will be to operate the pool in a range between 28-31°C. Therein lies the challenge for pool operators. The warmer the water, the more attractive the conditions become for bacterial growth. A great example of this is that the optimum temperature for Legionella growth sits at 37°C and keeping temperatures down will make conditions less attractive for bacterial growth. Also, as one increases the water temperature so does the air temperature, which does equate to substantial revenue costs. Air temperature is essential and to provide satisfactory air conditions a pool hall air’s temperature must aim to be
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the same temperature as the pool water, or up to 1 degree above, going to a maximum of 31°C (for a conventional public pool). Furthermore we should be aiming to keep humidity levels between 50% and 70%. Keeping temperatures down can often be difficult especially in summer and air circulation can assist in doing so. The air within a pool hall must be turned over constantly and operators should aim to circulate the air 3-4 times in an hour and in doing so, they should also replace air in the pool hall with around 30% of fresh air on each turnover. Evaporation by not adhering to these basic parameters can result in very costly: • Revenue implications • Uncomfortable lifeguard and staff conditions • Possible building fabric damage
OUTDOOR POOLS: USING THE RIGHT DISINFECTANT Applying sun cream is essential to many of us during the summer months and our pool water requires a similar method in protecting our disinfectants. Free chlorine is highly susceptible to degradation by UV light, so pools exposed to sunlight therefore require a sun block in order to protect and prevent this happening. Within outdoor pools we often achieve this by adding cyanuric acid, which provides a barrier of protection for the free chlorine – preventing this degradation occurring. The most common form of obtaining Cyanuric acid for the protection against UV
degradation is by using stabilised chlorine. This is most commonly found in a tablet form that contains both the chlorine donor and cyanuric (known as dichlor and trichlor). As the products dissolve they release free chlorine and cyanuric acid. cyanuric acid can be dosed separately using conventional pool sanitisers. We must though be very careful when increasing levels of cyanuric acid. Ultimately, yes, it will protect the free chlorine from the effects of the sun, but at levels outside recommended parameters it will also prevent the free chorine from disinfecting any potential bacteria. Even low levels of cyanuric acid will reduce the effectiveness of the free chlorine killing potential bacteria; so a proportional higher level of free chlorine is recommended. Also those indoor pools that are not susceptible to direct outdoor UV light are strongly advised against using stabilised chlorine. We also advise cyanuric acid levels are kept between 50 and 100ppm and should not be allowed to rise above 150ppm. The importance of effective backwashing filters and dilution cannot be over emphasised. For more advice or details on all STA’s Pool Plant Operator training courses call the STA, visit their website or email firstname.lastname@example.org STA 01922 645097 www.sta.co.uk
Take care when using stabilised chlorine. If it becomes wet, it will release chlorine gas. If mixed with a hypochlorite, it will explode. It will also react if mixed with many organic materials.
www.swimmingpoolnews.co.uk 23/07/2015 16:37
Published on Aug 1, 2015
Informing the pool and spa industry since 1959. Covering the UK's wet leisure market, SPN (Swimming Pool News) is the UK's longest running a...