swimming pools 2013 appendix 2 servicing the building

7/25/2019 Swimming Pools 2013 Appendix 2 Servicing the Building

1/10

Swimming Pools DesignGuidance Note

April Revision 004 1 Sport England 2013

DesignGuidance Note

Creating a sporting habit for life

SwimmingPoolsUpdated Guidance for 2013

Appendix 2Servicing the building

(To be read in conjunction with the main document)

May Revision 004 Sport England 2013

Energy implications

Energy usage in swimming

pool buildings

Water efficiency

Pool water quality Disinfection

Chemical dosing

Water softness

Filtration systems

Turnover rates

Water temperature

Air temperature and humidity

Electrical services Size of plant rooms

Plant room spaces

Air distribution systems


2/10


May Revision 004 1 Sport England 2013

Servicing the building

A safe, comfortable and attractive internalenvironment is essential in order to attract andsustain high levels of use. Good conditions arealso required for the lifeguards, teachers andspectators as well as achieving a reasonable lifeexpectancy from the building1.

The engineering challenge in achieving thefunctional requirements in a sustainable manner issubstantial2. For example:

Large volumes of swimming pool water needto be kept warm and continually treated todeal with the pollution from bathers

Air temperature, moisture content and airquality in the pool hall need to be carefullycontrolled

Potentially corrosive atmosphere needs to becontained and controlled in the appropriateareas

Internal acoustic conditions and noisebreakout to surrounding areas need to bemoderated.

It has been estimated3that the building servicesinstallation can account for between 30 and 50%of the capital costs of a modern pool.

The operational sustainability is therefore criticaland the full pattern of use, operation andmaintenance regimes of the swimming pool shouldbe allowed for within the services design. Theoperators requirements should be obtained at anearly stage in the design process.

Energy implications

Swimming pools use high levels of energy. It isimperative that the building footprint is minimisedat the design stage and internal volumes carefullymodulated to give an appropriate feeling of spaceand airiness. The building fabric should also bewell-insulated and effectively sealed from theoutside environment and any adjoining buildingelements.

Energy usage in swimming pool buildings

At the initial planning stages careful consideration

should be given to the energy and servicingstrategy for the building 4. It is important to agreean energy strategy early in the process as it couldimpact on the orientation, form and externalappearance of the building. A range of energysaving measures can be implemented that willreduce consumption. In deciding which is the most

The plant requirementscan be considered in thefollowing groups:

Incoming services: Water,electricity, gas and meters

Pool water treatmentsystem: Water filter(s)circulation pumps andpipework, chemical dosingequipments and backwashdisposal

Foul water disposal/drainage

Heating system: To heat

the pool water, areas of thebuilding and domesticwater supply includingstorage vessels andpressurisation systems

Energy/resource recoveryequipment: Heatexchangers, CHP plant,water re-use

Air-handling plant: Heatingand conditioning the pool

hall air and associatedspaces

Electrical distributionequipment

Water storage

Movable floor and/orbulkhead systems.

1The HSE publication HSG179Managing Health and Safety inSwimming Pools is a key reference.

2CIBSE Guide GPublic Health Engineering: Swimming pools.

3See Sports Council Guidance Note Swimming Pool - BuildingServices Nov 1994 and Sport Englands Affordable Community

Swimming Pools 2012.4The UK national planning system has recently been amendedto make sustainability its underlying principle (PPS1).


3/10



Table 1 Low/zero carbon techniques to consider

Be LEAN

Optimum orientation of the building and usageof glazing and/or solar shading to achieve:

Maximum benefit from natural light

Prevent glare

Optimum levels of solar gain withoutoverheating

Ancillary accommodation to the pool hall:

Natural ventilation

Night cooling

CO2or humidity detection to modulate fresh air

Pool cover / reduced ventilation

Enhanced thermal envelope and air permeability,

especially in the pool hall which is heated theyear round to 30C

Lighting:

High efficiency

Automatic controls

Direct lighting which is more efficient thanindirect lighting

Zoning of plant to specific areas to suit type andfrequency of use

Variable-speed drives on pumps and fans

Heat recuperation from extract air

Heat recovery from pool water / showers

Low water usage appliances

Power factor correction

Building and energy management systems

Pool water treatment plant:

Variable speed control of pumps to allow theturnover rate to be based on water quality

Altering UV output based on water quality

Use of appliances which have the highestavailable rating under the EU Energy EfficiencyLabelling Scheme

Be CLEAN

Combined heat and power (CHP): The yearround heat demand of pools makes them anideal application for CHP to be sized on theheat profile of the building to minimize heatbeing dumped

Use of energy sources beyond the siteboundaries such as district heating and/orcooling schemes for the wider use in the generalarea (which could include the use of CHP andabsorption cooling technologies).

Be GREEN

The use of on-site low/zero carbon technologies:

Photovoltaic panel

Wind turbines

Solar heating

Biomass heating

Air/ground source heat pumps

appropriate, whole-life costs, rather than initialcapital costs, should be considered and theminimum standards in the Building Regulationsshould be exceeded.

Energy usage in swimming pool buildings isgenerally high per square metre when comparedto other building types. The proportion of energynot controlled under the Building Regulation(unregulated energy) is also very high. For example,the electricity used for the pool water treatmentcould amount to 50% of the total electricityconsumption but is not controlled. It is important

that the energy strategy deals with all of the energyusage. Compliance with Part L alone could delivera building with unacceptable levels of energyconsumption.

The table below summarises low/zero carbontechniques to be considered when establishing theenergy strategy for a pool.

General power

5.5%

Space heating

53%

Water heating

25%

Fans and pumps

10%

Lighting 6.5%

Typical energy profile for a swimming pool building


4/10



Rainwater harvesting

Automated monitoring equipment for watermake-up

Grey water harvesting collecting water fromthe pool filtration system and showers to beused for WC flushing

Pool cover

Pool water quality

The quality of the pool water is of criticalimportance and will depend upon the design,

bather load and the ongoing operation. It is atechnically complex subject on which specificspecialist advice must be sought for eachparticular project. The Pool Water Treatment Group(PWTAG) publicationsSwimming Pool Water 2009and Code of Practice 2013are regarded as thestandard texts on the subject.

The selection of the most appropriate type of watertreatment system for a swimming pool will dependupon a number of factors:

Type and size of pool

Bather load

Characteristics of the source water supply

Pool operation and maintenance.

Comply with relevant localenergy policies:

e.g. the Energy Hierarchy within

the London Plan

Use less energy - be lean

Supply energy efficiently - be clean

Use renewable energy - be green

http://www.london.gov.uk/

Water efficiency

Swimming pools use large amounts of waterthrough the backwashing of filters, constant freshwater make-up (30 litres per swimmer), showersand cleaning. The reduction in water usage has anindirect benefit on energy consumption since lesswater is used, less water has to be heated andtransported using pump energy. The followingshould be considered:

Low water consumption taps and flushes fortoilets and urinals

Automatic shower controls


5/10



Table 2 Common disinfection measures

Pool type / bather load Conventional

disinfection

UV* O3*

Conventional / low6

Conventional / medium6 6

Leisure / high6 6

*Residual disinfection is required in addition to preventcross infection in the pool.

Disinfection

A conventional chlorine system has generallybeen considered to give an appropriate balance ofcapital costs, water and air quality, bather comfort,ease of control, maintenance and economy ofoperation. Sodium hypochlorite or calciumhypochlorite are commonly used to maintain afree chlorine level in the pool water to deal withthe pollution from bathers or other sources.Automatic control and dosing systems areregarded as essential to maintain safety, and giveobvious staffing and operational benefits.

However, water purification based on Ultra-Violet(UV) and to a lesser extent Ozone (O3) equipment

is commonly added into modern public poolinstallations. They both involve additionalequipment within the plant room areas, to treat thecirculating water and make subsequent disinfectioneasier. The benefits of such systems are:

Reduction in chlorine levels in the pool

Improved water quality particularly wherehigh bather load is expected

Improved air quality in the pool hall throughreduction in airborne chloramines associatedwith red eyes, sore throats aggravation ofasthma and bronchitis, particularly beneficial

to asthma sufferers, pool staff and long-termpool users.

However, such systems can add significantly tothe capital and running costs and can also requireincreased expertise from the operator.

There are particular safety and technical issueswith all water treatment systems, but as a generalguide, the use of purification systems are as setout in Table 2.

Chemical dosing

Chlorine is used in the pool water to kill bacteriaand prevent cross infections between bathers. Themost common chlorine donors are:

Sodium Hypochlorite (NaOCI)

Calcium Hypochlorite (Ca (OCI)2).

These individually produce free chlorine, achlorine compound for disinfection, and combinedchlorine, when free chlorine is combined withpollutants - the cause of the typical chlorine smellin swimming pools.

It is necessary to control the acidity (pH) balance

of the treated water. For example, dilutedhydrochloric acid (HCI) is added when sodiumhypochlorite is used.

Using other chemical treatments should bediscussed in detail with the water treatmentengineer. In particular, the use of SodiumBiSulphate (NaHSO4) should be avoided due to therisk of sulphate attack on cementitious grouts,renders and concrete. See the PWTAG publicationsfor more detail.

Pool water chemicals should always be dosed andmonitored by automatic equipment. Additionalmanual testing of water samples from the pool

should be undertaken regularly (at least twice aday) as an additional check on the system.

Water softness

The use of calcium hypochlorite is often preferredin areas of soft water since it is a calcium hardnessdonor to the pool. This will minimise the effects ofsoft water on cementitious materials used in thepool construction.

See the PWTAG publications for more more detailsand the appropriate design standards.

Ozone contact vessel and de-ozonising


6/10



Filtration systems

An effective filtration system is required to maintainthe clarity of the swimming pool water. For publicpools, sand filters are most commonly used. Inorder to maintain their effectiveness, these willneed to be backwashed regularly. This is achievedby reversing the flow through the sand beds andthen discharging the backwash water to a fouldrain.

The discharge to the drains is classified as tradeeffluent and the consent may place restrictions onthe timing, volume and/or flow rate discharge perday. Backwash tanks to hold the backwash watermay be required to allow a controlled discharge tothe foul drainage system.

The overall hydraulics of the system, the rating ofpumps and the position of inlet and outlet grills inthe pool tank need to be carefully designed toensure contaminants are effectively removed fromthe water. Deck level systems are most effective inremoving contaminants from the water surface.

To assist the filtration process, chemicals knownas flocculants are automatically added to the waterprior to it passing through the filters. Polyaluminium chloride is most commonly used and itforms a floc that helps trap fine particles,

microbes and pollutants in the water.

UV filtration system

Turnover rates

The time for the total volume of pool water tocirculate through the treatment plant and return tothe pool is known as the turnover rate. The perioddepends on the shape, size and use of the pooland should be considered early in the designprocess as part of the water treatment systemperformance requirements.

See the PWTAG 2009 publication and Code ofPractice 2013for more details and the appropriatedesign standards.

Typical filter installation

Pool TypeDepth(Metres)

Pool TurnoverRate (Hours)

Diving Varies 4.0 - 8.0

Swimming Varies 2.5 - 4.0

Learner/Teaching 0.5 - 1.5 0.5 - 1.5

Leisure 1.5 2.0 - 2.5

Table 3 Recommended turnover rates

The risk of contamination ofthe pool water can be

minimised through:

Careful design and locationof showers and toilets

Good housekeeping

Bather education.

(See Changing layouts in main

document Section 5.0 Developed

Design Considerations - Changingfacilities)


7/10



Pool 28-30C

Poolcalorifier

UV or ozonewater purification

Filters

Exhaust

Toilets

Changing rooms

Office

Pool hall

Fresh airsupply

Temperatureand humiditysensor


Temperaturesensor

Disinfection

Office/changingair handling unit

Heatexchanger

Extract fan



Pool cover

Grey waterharvesting

Samplecell

Luminaires withdaylight control

Luminaires withdaylight control

Glazing

Radiators, pipe-coils and underfloor heating

Hydraulic circuit design to considercontrol valve arrangement toradiators, pipe coils or underfloorheating as may be appropriate

Weathercompensationvalve

Low and zerocarbon technology

LZC

Fresh airsupply

Exhaust

Heatexchanger

Extract fan

Low lossheader

Boilers

1c above watertemperature

Pool airhandling unit

Glazing

Ventilation system

Key

Filtration system

Heating system

Monitoring sensor

Differential pressureand control valves

Motorised volumecontrol damper

Heater battery

Pump Separate foul

drainage to

poolside

Schematic services diagram for a typical small pool

Sodium hypochlorite bulk and day tanks

Water temperature

Over the years there has been a steady trend toincrease water temperatures to increasecustomer satisfaction. This is demonstrated inthe latest update of the PWTAG publication(2009)6that quotes maximum temperatures forswimming pools that are 1-2 degrees higherthan the previous edition of 1999 (see Table 4below). However the energy usage implicationsshould be carefully considered and it should be

Pool types / uses

Previous / currentrecommended maximumpool water temperatures

PWTAG1999

PWTAG2009

Competitive swimming anddiving, fitness training

27C 28C

Recreational, adult teaching,conventional main pool

28C 29C

Leisure pools 29C 30C

Childrens swimming As above 31C

Babies, young children, disabled 30C 32C

Hydrotherapy 35C

Spa pools 40C

noted that the PWTAG 2009 document alsoadvises that operators may run their poolsatisfactorily at temperatures 1-2 degrees lowerthan the recommended maximum.

Higher water temperatures may be attractive torecreational swimmers, disability groups andchildren, but are likely to be less suitable for fitnessswimming or competition. Higher watertemperatures may also have an adverse impact onthe water treatment and environmental controlsystems. See notes on the PWTAG web site on theproblems associated with operators running poolsat higher temperatures.

Table 4 Updated PWTAG pool water temperaturerecommendations

6Swimming pool water treatment and quality standardsPoolWater Treatment Advisory Group (PWTAG 2009).


8/10



720C is recommended for ancillary areas. SeeHSE documentHSG179 Managing Health and Safety in Swimming Pools.

8IEE guide and HSE Electricity at work regulation1989.

Air temperatures and humidity

Pool hall

Temperature and humidity control is required in thepool hall to maintain comfortable conditions forbathers. Air temperatures are usually kept at onedegree above the pool water temperature tominimise evaporation, relative humidity and airvelocity values as follows:

Air temperature: approx 30C(assuming 29Cwater temperature)

Relative humidity: 60% 10%

Air velocity: Approx. 0.1 m/s in theoccupied areas of thepool hall

Min fresh air supply: 4-10 air changes / hour

There should be even distribution and extractionof warm air from the pool hall so there are nodraughts on the pool surrounds or in the shallowend where people may be standing up.

The above conditions assume that the mean radianttemperature is approximately equal to or slightlyhigher than the air temperature. The atmospheric

conditions within an enclosed space are neverhomogeneous and vary with time and location.They are particularly influenced by bather activity.

Care should be taken that moisture and smellsfrom the pool hall cannot pass to adjoining areas.Effective moisture vapour barriers are required andgaps should be sealed to avoid potential damageto the building elements, particularly whereservices and ducts pass through walls. A negativepressure difference between the pool hall andadjoining areas, such as changing areas, can beused to help contain the pool environment.

See PWTAG 2009 for the importance of the

ventilation system in removing airborne disinfectantby-products and contaminants from the pool halland ensuring an adequate distribution of fresh air.

Spectator area

Spectators in adjacent seating and viewing areaswill require a lower temperature created by anincreased fresh air supply as follows:

Air temperature: approx 25C7

Relative humidity: 60% 10%

Air velocity: approx 0.3 m/s

Min fresh air supply: 10 air changes/hour

However, where such additional air supply systemsare considered, care should be taken to avoidcooler air dropping into bather areas and causingdiscomfort.

Changing and clothes storage areas

The airflow should be evenly distributed anddesigned to remove smells, particularly in changingareas and toilet areas. There should be no draughtscaused by airflow. In order to provide comfortableconditions as people change and move back intothe public areas, the following conditions shouldbe provided:

Air temperature: approx 24-25 C

Min fresh air supply: 10 air changes / hour

This should be arranged as a separate systemfrom that for the main pool hall. Some additionalfresh air supply within the system could bebeneficial in vanity areas where people would bein their normal clothing.

Baby changing accommodation should haveseparate rates of ventilation.

Electrical services

Special care should be taken with electrical

services in view of the damp warm and corrosiveatmosphere 8. Mains voltage must not beaccessible within the pool hall.

Light fittings

For general lighting design issues, see MainDocument Section 5.0 Developed DesignConsiderations - Pool Hall - Artificial Lighting.

There are particular issues with underwaterlighting:

Size/type needs to suit the pool beingilluminated

Reliability

Expected lamp life / replacement cost

Ease of re-lamping

Water safety no fittings should exceed 20Voperating current / need for transformerslocated relatively close to each fitting.

Where movable floors are used, the underwater lightfittings will need to be flush with the pool wall.

Some underwater light fittings may also sufferfrom high temperatures at the glass lens, and inorder to avoid the risk of bather injury, the


9/10



9PWTAG / Sports Council Guidance Note: Swimming poolsBuilding Services.

operational temperature of the surface of the glassshould never become so hot as to be uncomfortableor dangerous.

Sizes of plant rooms

Plant rooms should be located in close proximity tothe areas they serve in order to reduce service runs,system losses, and minimise fan power. Theyshould also be sized to give good access to theequipment that they house and allow for operation,maintenance, replacement and deliveries.

Typically, the pool water treatment plant roomshould be between 15-30%9of the water area thatit serves.

An economical solution is to locate the air-handlingplant at high-level, providing there is adequateaccess. A rule of thumb to calculate the overallarea required is to allow approximately 15% of thepool building area.

Plant room spaces

The location, size and distribution of the plantwithin the building needs to be considered early inthe design process along with the operation andmaintenance factors.

The plant room spaces should:

Allow the plant and equipment to be installed,commissioned, operated and maintainedsafely and efficiently

Allow for service access and removal/replacement of all individual elementsincluding bulky items such as filters, whichmay require extra wide access doors orremovable panels

Minimise service runs, with water treatmentplant located close to the deep end of the pooltank

Locate pool water circulation pumps at thesame level as the bottom of the deepest waterso that they are continually flooded

Allow for the delivery and storage of chemicalsin a separate, ventilated area, ideally at groundfloor level. Include appropriate safetyarrangements such as bund walls for chemicalstorage tanks and dosing equipment andemergency drencher and eye wash facilities.The acid and chlorine stores will requireseparate ventilation system

Ensure adequate ventilation rates to all plantroom areas. If ozone treatment is used, providean automatic ozone detection alarm systemand consider the need for similar systems forchlorine and carbon dioxide

Ensure adequate floor drainage in the plantroom and provide a hosepipe point

Provide an accessible balance tank toaccommodate water displaced by bathers (fordeck level pools only). Access via a lateralaccess way from the plant room is preferredto manholes in the pool surround floor

Provide holding tanks if required for the maindrainage system to deal with the quantity offilter backwashing water (can be separate fromplant room)

Allow space for new technology such ashousings for underwater camera control panels

Provide adequate space for a workbench,desk and chair, tools, maintenance manualsand so on

Ensure flues, air intakes, ventilation and extractlouvers/cowls are positioned away from publicand residential areas

Ensure safe access to all plant/equipment

requiring regular inspection

Allow for control equipment and underwaterpool windows associated with computerassisted underwater pool supervision

Be connected to all emergency alarms.

Access to plant rooms

Access to the plant room should be available bothinternally, via a controlled access point, andexternally, via a delivery entrance. All doorsleading to the plant room must have secure lockingmechanisms fitted to prevent access by untrained

staff and members of the public.

If an external service yard is provided, the externalaccess should incorporate the provision of a steelshutter door system. The door should be fittedwith a high-security locking system and beconnected to the centres security alarm. The idealopening size is 3.0 m wide by 3.0 m high tofacilitate filter replacement. There should also bean additional side door for external access to theplant room, to reduce wear and tear on the steelshutter and the probability of it being left openduring a period of frequent use.

Doors in the plant room should be of a heavy-dutynature and have a minimum opening width of 1.0 m(1.5 m preferred).


10/10



Air distribution systems in the pool hall

There is a marked move away from supplying airthrough overhead ducted systems to the use ofducts incorporated at low-level into the pool tankdesign. These systems either sit adjacent to thepool water overflow system or are set at low-levelaround the perimeter of the pool hall. If locatedunder glazed curtain walling, they have theadditional benefit of reducing the condensationthat can form on the windows.

Low-level systems need to be designed to preventingress of water due to flooding from the poolsurround or ground water. This can impact uponthe pool hall environment and result in damage to

the air handling plant. Integrating drainage systemsmay not resolve the problem as traps will inevitablydry out allowing the passage of foul air into thebuilding.

Overhead ducting is still specified in some pooldesigns and as with direct lighting units, it canprove difficult to avoid positioning directly overwater and maintenance becomes very problematic.

The ductwork fixings must be carefully selected asthere have been several cases of ducting sectionsfalling from height due to corrosion and subsequentfailure of the fixings studs etc. Regular inspectionof all ventilation ductwork and fixings must takeplace. This requires suitable access.

swimming pools 2013 appendix 2 servicing the building

Documents