Issue 40 – July 2012
A heightened interest in leisure and concern for healthy lifestyles are driving demand in affluent societies for fitness installations – including swimming pools – in clubs, apartment complexes, and even homes. Electrical equipment is an integral part of swimming pool installations and must meet specific requirements to suppress the risk of electric shock. As young children are particularly at risk of accidents and of drowning, special precautions, including the fitting of alarm and other systems, must be taken to ensure their safety.
An uneasy relationship
Pool equipment and maintenance systems include a variety of electrical devices for heating, cleaning, sweeping, pumping, and lighting. There are also automated systems, controllers, and safety equipment.
As risk is always involved when water and electricity mix, the design and installation of such equipment and systems must meet strict criteria to protect individuals against electric shock. These criteria apply to electrical installations for swimming and paddling pools and their surrounding zones, and for basins and fountains as well as 'areas in natural waters, lakes … specially intended to be occupied by persons for swimming, paddling, and similar purposes'.
IEC 60364-7-702, Requirements for special installations or locations – Swimming pools and fountains, defines the dimensions of three zones in which such equipment may be installed and stipulates what may go where. Several IEC TCs (technical committees) and their SCs (subcommittees) prepare international Standards for these electrical installations. They include TC64, Electrical installations and protection against electric shock, TC 61, Safety of household and similar electrical appliances, and SC 34D, Luminaires.
Low water temperature may restrict pool use to just a few months of the year. Heating of pools is highly advantageous and has become easier and cheaper in recent years with the advent of more energy-efficient and low-cost equipment designed for small pools and relying mainly on heat pumps.
Heat pumps transfer heat mechanically from a source to raise the temperature of the target installation. They are classified by the source of their heat, which can be extracted from the air, the ground, or from a circulating water loop within a building.
IEC SC 61D, Appliances for air-conditioning for household and similar purposes, prepares international Standards for electrical heat pumps.
Air-source heat pumps are most widely used for pools. They have become more affordable and recent advances have greatly improved their efficiency during cold weather. A single so-called 'multi-split' unit can serve either as heat pump in heating mode, or as air conditioner in cooling mode, or can do both simultaneously. Air-source heat pumps are also used to heat water by recovering waste heat from buildings' exhaust air.
In order to save energy and support the environment many consumers are fitting solar powered pumps and heaters to their swimming pools. Solar power is especially suitable for swimming pools since they are, for the main part, installed in sunny places.
Clean and bright
Cleaning of pools is essential for health reasons and to avoid contamination. It relies on mechanical and chemical processes; the latter comes into play after pools have been cleaned of debris. Cleaning involves removing dirt, leaves, and other waste from the pool's surfaces and water. This is done by hand or using mechanical or electrical devices. Cleaning robots capable of operating independently may be used.
TC 61 prepares Standards for household and similar electrical appliances. These apply to 'vacuum cleaners and water-suction cleaning appliances' including 'automatic battery-powered cleaners'. When there is a requirement for the devices to be connected to power outlets, IEC 60364-7-702 (Low-voltage electrical installations – Part 7-702: Requirements for special installations or locations – Swimming pools and fountains), prepared by TC 64, sets out the distances at which permitted gear may be installed safely, as well as the characteristics of wiring and current-based equipment used in swimming pools.
Lighting can enhance the swimming pool environment and overall user experience. Lighting fixtures may be installed outside the pool, above ground or recessed, and underwater in appropriate housings. Light can be delivered via a variety of bulbs, LEDs or fibre optics.
SC 34D published IEC 60598-2-18 Luminaires – Particular requirements – Luminaires for swimming pools and similar applications. This international Standard details general test requirements, the classification of luminaires and characteristics for construction. It also describes tests for mechanical strength and corrosion and many other features for light fittings that are used in the swimming pool environment.
Prioritising children's safety
Equipment used for heating, cleaning, or lighting pools enhances the satisfaction of users and should be safe when properly installed. Nevertheless, children, particularly very young ones, face a high risk of accidents in these locations. In many countries accidental drowning, particularly in domestic pools, is a major cause of accidental deaths.
According to the US CDC (Centers for Disease Control and Prevention), 'Drowning is responsible for more deaths among [US] children aged 1 – 4 than any other cause except birth defects. In 2009, among children aged 1 – 4 who died from an unintentional injury, more than 30% died from drowning and among these most drownings occurred in home swimming pools'. Many other countries report similar findings.
Proper adult supervision and vigilance are key to ensuring child safety and preventing drowning. However, most pool accidents are over in less than 5 minutes – and who can be vigilant all the time? Fortunately, systems exist that can help improve poolside safety.
Pool safety alarms provide extra protection for children. Various systems are available depending on features required and type of pool involved, budget availability, and technical requirements. Just as in an industrial environment, physical access to the pool area can be blocked with fences and doors and/or controlled with gate, door, window and perimeter alarms. These can be mains or battery-operated and use different types of sensors – motion or pressure activated, laser or infrared lights – to sound an alarm when a child enters a restricted or hazardous area.
In-pool alarms are the system of last resort: they react when a child falls into the water. Floating wave sensors are battery powered and mounted on the edge or in the pool. They sense water displacement when an object or a person weighing more than 7 – 8 kilos enters the pool, sending a signal to a remote receiver that is either in the home or carried by an adult. The receiver then emits an alarm. These systems can be used with pool covers or solar blankets. Their main disadvantage is that someone must be physically in the water before an alert is sounded.
A number of IEC TCs are active in the preparation of Standards for components used in these systems. Among them are SC 47E, Discrete semiconductor devices, which develops international Standards for sensors, and TC 79, Alarm and electronic security systems.
Standards supporting a buoyant market
As the market for swimming pools and all associated equipment keeps expanding globally, manufacturers of all electrical equipment used in the pool environment will rely more and more on IEC standards from a number of TCs and SCs to ensure that installations are performed correctly and to safeguard all of the gear designed to make the swimming experience more enjoyable and safer for all.
Reproduced from IEC newsletter, e-tech, June 2012
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- NZS 8500:2006 Safety barriers and fences around swimming pools, spas and hot tubs
- IEC 60364-7-702:2010 Low-voltage electrical installations – Part 7-702: Requirements for special installations or locations – Swimming pools and fountains)
- IEC 60598-2-18:1993 Luminaires – Particular requirements – Section 18: Luminaires for swimming pools and similar applications
- Keeping intruders at bay, Touchstone July 2012