Structural Design Guidelines For Indoor Pools

Plant Room Space Requirements​

Frequently insufficient space is allowed for the plant room area. The equipment necessary to deal with the requirements of an indoor pool is considerable - pumps. filters, boilers, air handling units etc. Sufficient space must be provided for all the equipment together with adequate access for service and maintenance.​

If the plant room is to be used as a plenum chamber for the pool hall air. i.e. the pool hall air is drawn into and through the plant room, then the plant room must be thermally insulated to the same high standards as the main pool hall. In addition, only fuel boilers fitted with a balanced flue, as opposed to a conventional flue, can be positioned within the same area. Care must also be taken with the storage and use of chemicals.​

The plant room equipment will obviously produce a level of noise during operation. Consideration must be given to potential noise and vibration transfer. For example, the plant room should not be located near to bedrooms and should ideally be positioned away from occupied areas. Be aware that vibration can also be transmitted through walls, ceilings and ducting. Some noise will invariably be transferred into the pool hall area how intrusive this will prove is dependent largely on the acoustics of the pool hall.

​Building Structural Insulation:

Pool halls are normally maintained at temperatures significantly higher than those normally experienced in domestic dwellings. Therefore, in order to conserve energy and limit condensation, it is important to ensure that the structure is insulated to a level which is at least equal to or greater than the current building regulations.​

The roof/ceiling should have at least 150mm of glass fiber insulation or equivalent. All cavity walls should have insulation between the two skins.​

All glazing should be at least double-glazed. Ideally, triple glazing should be used, but the capitol cost often proves prohibitive. Internal doors and windows should also be well-sealed to prevent the pool hall air from migrating into the adjoining areas.​

​The building should be well sealed to prevent cold air from seeping through gaps around doors and windows etc.

Although the overall structure may be well insulated and thus condensation-free, there can be points where structural members such as lintels or RSJ's cause cold bridging resulting in localised condensation forming on the interior of the fabric. When designing the structure, this can be averted by adding additional insulation and vapour sealing to problematic areas.

Building Structure Interior Finishes

​The selection of materials used for indoor swimming pools is critical as they are continuously exposed to higher levels of moisture than in other interior applications.​

​In rare cases. for instance in the event of a power cut or if the environmental control equipment is being serviced, the interior fabrics may be exposed to saturated air.​

​The interior fabrics used must therefore be able to resist excessively humid conditions over a short period of time without deteriorating.​

​As a rule the materials used for the internal finishes should be of the same specification as those used for exterior use. For instance plaster, plasterboard and artex finishes are unsuitable due to their hygroscopic nature, whereas waterproof render, tiling and treated timber are far more suitable finishes.

Any timber used must be conditioned for use in damp areas or, if kiln dry timber is used, allowance must be made for expansion under pool hall conditions.

Adjacent Rooms to Pool Hall​

​Provision must be made for adequate heating and ventilation of any rooms adjoining the pool hall such as changing, toilet, or storage areas to prevent localised condensation.

Glazing​

The majority of indoor pools are fitted with full height patio doors, which are generally the most vulnerable points for condensation.​

Even if the pool hall environment is correctly controlled some surface condensation can still be anticipated on double glazing during the coldest winter months.​

If this is not acceptable the use of triple glazing should be advised.​

​Due to the comparatively poor thermal insulation value of glass, the overall heating costs for the project will largely depend on the amount of glazing within the design.​

​In order to minimise surface condensation and to make the most effective use of the warm air curtain effect from the ducting channel, the following points should be noted :​

• All glazing used in swimming pools should consist of sealed double glazed units and not secondary glazing added to existing single glazing.​
• The window frames should not be made of soft wood, but aluminium or ideally PVC which will not be effected by condensation from the glass.​
• All window frames MUST be fitted with thermal breaks.​
• In order to maximise the effect of a warm air curtain and minimise condensation. the glazing should ideally be level with the inside surface of the walls.​
• The use of Georgian sole double glazing should be discouraged as the design of the frames can prevent the warm air curtain effectively reaching the actual glazing.​
• Recessed windows of any description should be avoided as it is difficult to achieve effective air distribution into the recessed area resulting in increased condensation.
• With sliding patio doors the seal should be airtight. as cold air entering through gaps in the seal is often the cause of condensation on the glass.​
• It is recommended that any external glazing positioned in close proximity to a spa should be triple glazed due to high localised humidity levels in such areas.

Glazed Enclosures​

​Fully glazed conservatory type enclosures are often an attractive convenient and comparatively inexpensive alternative to a conventional construction.

​However, consideration must be given to the characteristics of such an enclosure

• ​During the summer period due to the considerable effects of solar gain, these structures tend to overheat and can become uncomfortably warm if not effectively cooled through ventilation.​
• During the winter period the high heat loss through the glazing will be reflected in the heating costs of the enclosure. Therefore the requirement for the use of a pool surface cover is enhanced.​
• Surface condensation is often more apparent on the glazing during cold weather. Due to the difficulties involved in covering such a large area of glass with a curtain of air from the ducting channel.​
• The roofing materials will also be particularly prone to condensation under such conditions.​
• Increased condensation can be anticipated on the window frames of some enclosures as they are often not fitted with thermal breaks.​
• ​Cold bridging through the main supporting structure of some enclosures may also result in condensation.​
• Increased heat loss and condensation can also be experienced as a result of the difficulties involved in completely sealing some enclosures.

Pool Hall Roof Vapour Barrier​

​We recommend adopting a warm roof design for any pool hall environment, however in all roof construction to prevent the moisture in the pool hall air from penetrating through the ceiling insulation and condensing in the cold sectors of the roof, provision must be made for the inclusion of an effective vapour barrier.

Please note

• A material that is waterproof is not necessarily vapour [gas] proof​
• Recommended material: Monarflex 275 or equivalent.​
• The method of installation should ensure that the vapour seal is complete and secure.
• Care should be taken to ensure that individual trades do not penetrate the​ vapour barrier with fixings etc.​
• If using pre-assembled insulation showing already fitted with an approved vapour bandied it is essential that the joints between the separate panels are also completely vapour sealed and insulated.​

In practice no vapour barrier will be totally effective as a small amount of moisture can still be passed through the insulation to cooler areas of the roof, it is therefore essential to provide space above the insulation which can breathe to the ambient air, allowing the moisture to escape and not concentrate.​

Pitched roofs must have ventilation provisions [building regs]. Flat roofs can either have breathers in flat surfaces or ventilation through the edges.​

​This will ensure that the insulation remains dry and effective and that the roof structures will not be subject to condensation and mould growth etc.

Pool Hall Air Migration​​

Ideally, there should be a pressure differential between the pool hall and any adjoining areas to help prevent the pool hall air from migrating into these areas.​

​Roof Lights​

The use of roof light glazing is discouraged as they can often become a trap for localised condensation, in addition, it is difficult to provide a good seal between the vapour barrier and the roof light making the surrounding area vulnerable to condensation.​

If roof lights are required it is strongly recommended that they be triple glazed with thermal breaks in the frames.​

​If twin or triple wall polycarbonate sheeting is to be used, condensation can be expected during the winter months. Care should be taken to ensure that the edging of the sheets are properly sealed.​

​The very high levels of solar gain that such materials can produce should also be considered.

​Stretched Ceilings​

​A plastic stretched type ceiling offers a number of benefits and provides an excellent vapour ban barrier. However such ceilings are prone to movement in level when exposed to the normal air pressure differentials which a typical ventilation system may be expected to produce. Therefore:​

​If any cables or lights are incorporated within the ceiling, due allowance should be made for movement in the length of the cables.​

​The roof structure behind the stretched ceiling should be at a sufficient distance from the ceiling to ensure that the two do not come into contact should the ceiling level move upwards.​

​The fixings supporting the ceiling should be sufficiently strong enough to cope with any pressure load that the ventilation system may place upon the area of the ceiling.

FURTHER INFORMATION

For further information or to book our design consultancy service please contact us.