ENGINEERING STANDARDS SECTION 5 – PLUMBING 5.9. SWIMMING POOL SYSTEMS...........................................................................326 5.9.1. GENERAL.....................................................................................................326 DESIGN CRITERIA..............................................................................326 5.9.3. SWIMMING POOL SYSTEM CYCLE....................................327 5.9.4. ENVIRONMENT & ENERGY CONSERVATION..................332 5.9.2. InterContinental Hotels Group – Asia Pacific 2005 Revision All Rights Reserved 325 ENGINEERING STANDARDS SECTION 5 – PLUMBING 5.9. SWIMMING POOL SYSTEMS 5.9.1. GENERAL A dedicated water treatment system should be provided to serve pools for wading, swimming or diving. The water should be provided initially as described in section 5.1, and then recycled through the swimming pool plant for reuse. The supply to the pool should be heated to the required temperature or in very hot climates, may be cooled prior to serving pool. 5.9.2. DESIGN CRITERIA Water serving pools should be fresh and clean, with the distribution to the pool designed so that the quality and temperature of the water is maintained at acceptable levels. All critical chemical parameters shall be monitored and maintained automatically within the range +/- 10%. The preferred water quality is as follows: Table 5.9.2.1 5.9.2.1 PH Alkalinity Calcium Hardness (Calcium Carbonate) Total Dissolved Solids Acceptable Range 7.2 to 7.8 7.27.8 75 to 250mg/l 75250/ 100 to 500mg/l 100500/ less than 3000ppm 3000ppm 7.4 to 7.6 7.4 7.6 120 to 180 mg/l 120 180/ 150 to 200 mg/l 100 200/ Less than 1500ppm 1500ppm Ideal Below are the suggested target temperatures for various types of pool Table 5.9.2.2 5.9.2.2 Pool Type Temperature Range Leisure Pool 27°C to 29°C 27°C 29°C Wading/Paddling Pool 28°C to 30°C / 28°C30°C Diving/Competition Pool 26°C to 27°C / 26°C 27°C Plunge Pool - Adjacent Saunas 16°C to 20°C - 16°C20°C Pool plant should be self regulating and include automatic monitoring of pH levels chemical levels and temperatures maintaining acceptable levels. InterContinental Hotels Group – Asia Pacific 2005 Revision All Rights Reserved 326 ENGINEERING STANDARDS SECTION 5 – PLUMBING 5.9.3. SWIMMING POOL SYSTEM CYCLE A) Distribution System and Pool B) Filtration and Discharge to Drain C) Disinfection Top-up With Pre-treated Water D) E) pH Level Control pH F) Heating InterContinental Hotels Group – Asia Pacific 2005 Revision All Rights Reserved 327 ENGINEERING STANDARDS SECTION 5 – PLUMBING A(ii)FB(iii)ECD(i) Potable/Pre-treated Water Top-up (ii) Non-Potable Top-up Prior to Treatment Process (iii) Filtered Deposits to Drain/Non Potable systems A) Distribution System and Pool Ideally, plant serving pools should be sited within, their immediate vicinity. A single plant room should serve multiple pools, arranged with run and standby facilities to minimise disruption to pool use during plant maintenance. Pipework distribution should be arranged so that any pool, whatever pool size, will have a minimum of 2 suction/drain connections on the circuit to the pump. Short-circuiting of water should be avoided. Pools with high numbers of infant usage should have a higher circulation rate than those for adult use. Circulation pumps should be run and standby. (i) Suggested turn over rates: Infant/Shallow section of Pools Refreshed Every 30 minutes 301 Adult/Deep Section of Pools Refreshed Every 150minutes / 1501 B) Filtration and Discharge to Drain Filters within the pool circulation systems should be installed as run and standby. The filtration selected should achieve a visibility of at least 12m giving clear views of all parts of the pool bottom. InterContinental Hotels Group – Asia Pacific 2005 Revision All Rights Reserved 328 ENGINEERING STANDARDS SECTION 5 – PLUMBING Mild steel high-pressure sand filters should be rated at 12-13l/s per square meter of filter area. The filters should be protected internally to prevent corrosion. Fibreglass sand filters may be used as an alternative to mild steel. Rate of flow indicators should be installed to monitor the rate of low from the filters. A pressure switch should be fitted prior to the filter for backwash/rinse requirements. Pipework should be installed in polybutlene with corrosion resistant fittings. Where filtration alone will not achieve water clarity required, use flocculates, eg, aluminium sulphate fed by automatic dosing pumps. C) Disinfection The annihilation of bacterial infection of pool waters may be accomplished using several methods. Chemical parameters shall be monitored and maintained automatically via dosing pumps etc. Chlorine application, via sodium or calcium hypochlorite additives or electrolytically generated in situ. Bromine additives. Ozone additives in conjunction with low level chlorination. Ultra violet light application with low dilution of chlorine additive. Chemical additives all have side effects upon pool users to greater or lesser degrees where not carefully controlled. Chlorine gas is not recommended, as stringent safety precautions must be observed. Ozone is hazardous to health and must be removed from the water after use. Monitor disinfection level daily to ensure appropriate levels of chemical dilution are present (eg, 0.6 - 1ppm free available chlorine dependant on application). Types of Treatment Treatment Benefits Tried and trusted Chlorine method of pool water treatment Residual chlorine content in water maintains disinfectant properties in pool after treatment Problems Requires careful control can cause irritation of eyes, discolour hair. Unpleasant fumes which can be lethal in case of accidental release. Renders discharged water useless for irrigation if it is to be Application Larger pools with trained maintenance staff, used to handling chlorine. Where water not used for irrigation. Where large proportion of infants using pool. InterContinental Hotels Group – Asia Pacific 2005 Revision All Rights Reserved 329 ENGINEERING STANDARDS SECTION 5 – PLUMBING Treatment Benefits Problems Application recycled, but can be used for urinal/WC flushing. Fumes can damage building finishes. Bromine Residual bromine Can cause skin content in water irritation, sore throats maintains and stinging eyes. disinfectant Renders discharged properties in pool water useless for after treatment. irrigation can be used for flushing Small pools with competent maintenance staff. Where large proportion of infant users. Ozone Powerful disinfectant, oxides impurities without providing side effects. No residual chemicals discharged water can be recycled more readily. Once added, must be removed again prior to use. No residue, so water can become contaminated. It is recommended that a small amount of chlorine is added to maintain pools disinfectant qualities but this should be balanced with final use. Where greatest proportion of users are adult, and water to be recycled for irrigating, etc. Where there is limited space of storing chemicals, or not large enough plant complex to warrant fully trained pool plant engineer. Ultra Light Violet Once fitted to No residue, so water Where greatest proportion of system is very can become users are adult, and water to InterContinental Hotels Group – Asia Pacific 2005 Revision All Rights Reserved 330 ENGINEERING STANDARDS SECTION 5 – PLUMBING Treatment Benefits simple to maintain and manage. No side effects. Problems contaminated. Small amounts of chlorine to be added or more frequent pool water changes instituted. Application be recycled for irrigating, etc. Where there is limited space of storing chemicals, or not large enough plant complex to warrant fully trained pool plant engineer. D) Top-up With Pre-treated Water Where potable/pre-treated water is available for pool use, introduce the fresh water prior to heating. As a guide, approximately 25 litres of freshwater per bather may be introduced. Where water is non-potable, it should be introduced to the system prior to filtration and disinfection. E) pH Level Control Control of pH levels is particularly important where chlorine is selected as the medium used for disinfection of pool waters. Sodium bicarbonate is used to reduce the acidity of water treated with chlorine gas. Where chlorine donors have been introduced such as sodium or calcium hypochlorite, the pH tends towards hardness, therefore treatment to increase acidity should be applied using one of the following: • Calcium chloride • Carbon dioxide • Sodium bisulphate • Hydrochloric acid The importance of maintaining balanced pH levels is chiefly relevant to the protection of parts of the pool system susceptible to corrosion from either excessive alkalinity or acidity of pool waters. Additionally, chlorine loses its effectiveness if the level of pH risers too high. Magnetic Water Conditioners An alternative method of protecting the system is by application of magnetic water conditioners. The conditioners impose a magnetic charge upon the particles suspended in the systems water. This prevents the particles adhering to internal surfaces susceptible to scale such as pump rotors, heating coils, etc. They have also been found to be beneficial to the disinfecting process. Where magnetic InterContinental Hotels Group – Asia Pacific 2005 Revision All Rights Reserved 331 ENGINEERING STANDARDS SECTION 5 – PLUMBING water conditioners are provided, pH monitoring and control are still required to maintain levels in the range of 7.2 - 7.8 mentioned above. (Refer to Drawing 5.9.3.) Before selecting magnetic water conditioner refer back to IHG for approval. F) Heating When assessing size of plant and method of heating pool water, careful consideration should be taken with regard to expansion of pool structure, concrete shell, tiling, etc. As a guide the rate of heat up from cold to operating temperatures should be no greater than 0.5°C per hour. The characteristics of heat demand for swimming pools, are the most suitable match for slow heat gains from other systems utilising heat exchangers, for example: a. Solar collectors, transforming solar energy into useable heat. b. Heat pumps where unwanted heat from refrigeration plant is transferred to the pool water. c. District heating schemes. d. Hot springs e. Heat can also be recovered from within the swimming pool plant from the filtration backwash. Each of these systems should be supplemented with electric, gas or oil fired boilers via heat the exchangers. These should be designed to compensate for times where the initial source is insufficient. Where more than one swimming pool is served from a single plant, each pool should have its own dedicated heat exchanger, sized to match the duty required. ,, G) Pool floor cleaning Floor cleaning shall be accomplished by automatic floor cleaners, which shall be provided. 5.9.4. ENVIRONMENT & ENERGY CONSERVATION Out door pools should be covered with an insulating cover when out of use. This not only conserves energy by reducing heat loss outside hours of sunshine effectively and prevents evaporation but also restricts use to when lifeguards/poolside staff are available for supervision. Where possible, “waste water” from filtration backwash should be recycled for WC or urinal flushing. Discharge water that is contaminated with chemical additives should be disposed in a manner that will not pollute local water supplies, local water courses, lakes, streams and the like. Any soakaways or leaching pits should be kept remote from wells or boreholes where contaminated water may be withdrawn inadvertently. InterContinental Hotels Group – Asia Pacific 2005 Revision All Rights Reserved 332 ENGINEERING STANDARDS SECTION 5 – PLUMBING InterContinental Hotels Group – Asia Pacific 2005 Revision All Rights Reserved 333
