Is your client craving a spa pool to escape the cold, or planning for refreshing dips come summer? Creating successful outdoor swimming pools and spas is an operation that requires specialised design and construction skills, and these days many landscapers are the ones providing this expertise – either for the structure itself or the surrounding areas. Both have stringent requirements, so read on to find out more
Skilled or not, always obtain specialist advice on the pool options that are suitable for a particular site or location.
Large amounts of freshwater are required for swimming pools and spa pools, and chemical (often chlorine) treatment is required. Rainwater collected from roofs and other surfaces may reduce the demand for reticulated water, but the amount collected, when compared to the total volume of water required annually, is likely to be minor.
Chemicals used to keep pools clean can pose a health hazard. Advice on pool water treatment can be obtained from the British Pool Water Treatment Advisory Group (www.pwtag.org).\
An energy-intensive process
The large amounts of energy required to heat pools can be mitigated by good design and pool management. The use of insulating covers and dark colours on the pool sides and floor can help reduce heating costs. Solar water heating systems can help temper the water.
Factors that need to be considered are:
The bearing capacity of the ground or structure under and adjacent to the pool access for plant and equipment.
The level of the water tables and the need to accommodate groundwater pressure and/or the drainage of groundwater.
Pool construction systems and materials that are to be used (in-situ concrete, precast concrete, concrete masonry zand plaster, sprayed concrete, safety glass, fibreglass or framed with supported fabric liners).
The size and shape of the pool – the larger the pool, the greater the water pressures that have to be resisted by the pool structure.
The fencing to ensure the pool is safe (ensuring uncontrolled access by young children is prevented) – the Fencing of Swimming Pools Act does not apply to swimming pools where people are employed to provide supervision, such as public swimming pools, but does include spa pools.
The surrounding surface and pool finishes, particularly when saltwater is being used in the pool.
Applied finishes (paint, tiles) to the pool walls and floor.
Slip resistances of walk-on areas likely to be wet.
Drainage of the pool water.
Location of the pump and filtration/cleansing plant.
The heating system - gas fired, solar or electric.
Pool edge details.
Prevention of backflow contamination of potable water supply.
Heating costs – spa pools can be purchased with high levels of insulation to reduce the costs of heating the water.
Swimming pool fencing
Minimum barrier requirements are contained in NZS 8500:2006 and Acceptable Solution F9/AS1 for NZBC Clause F9 Means of restricting access to residential pools, which states that a pool barrier (not on a property boundary) must be:
At least 1.2m above the ground, measured on the outside of the pool barrier.
At least 1.2m above any permanent projection located within 1.2 m of the outside of the fence (see F9/AS1 Figure 2).
Constructed in a way that prevents young children (under five years of age) from gaining access.
Built of durable materials (a minimum design life of 15 years).
It should be noted that most spa pools (ie, less than 5m2 water surface area) can achieve compliance with a suitable locked cover over the spa pool and a pool edge height greater than 760mm above surrounding levels. Refer to F9/AS2 for detailed guidance and the local council should be consulted for specific rules.
Detailed construction of pool barrier fences requires:
Fence supports, rails, rods, wires, braces and so on to be designed and constructed to prevent them from being able to be climbed (see F9/AS1 for details).
Non-vertical rails exposed on the surface of the pool barrier to be more than 900mm apart vertically.
Perforated netting to have a maximum mesh aperture of 10mm (for 1200mm high) and 35mm (for 1800 to 3000mm-high barriers/fences).
Vertical gaps between fencing members to be no wider than 100mm and vertical gaps between palings to be no wider than 10mm (see Figure 1, F9/AS1).
Horizontal gaps to be less than 10mm wide.
Gaps between ground and the bottom of the fence to be less than 100mm.
Other areas of compliance
The enclosing of swimming pools and pool areas with barriers is one means of compliance with the regulations.
Other protections may include:
A fully enclosed structure or building housing a swimming pool.
A pool in a contained area of a building.
The outer wall of a building (depending on doorways and windows).
An 1800mm-high boundary fence constructed in a way that meets the minimum requirements outlined in F9/AS1.
There is a risk with boundary fences that a neighbour is free to install a trellis or other easily climbable arrangement on their side of the fence, which would make the fence non-complying. Ensure there are no climbable objects (on the neighbour’s side) within a 1200mm radius from the top of the barrier (see Figure 2, F9/AS1).
Doors and gates to the pool (or spa pool) area are to be constructed in a manner that restricts access to children under five years old. Details of construction must conform to the minimum requirements in F9/AS1.
Access points must:
Be outward opening, away from the pool area.
Have latching devices located out of reach of young children.
For doors from a building, be fitted with a latching device as per section 4.2 in F9/AS1.
For windows that give access to a pool area, be fitted with screens or devices to restrict the window opening to 100mm wide.
By following the points outlined in the article and F9/AS1, you can ensure you’ll be providing clients with a quality service that’s compliant with regulation.
This article was first published in BRANZ’s Landscape Construction book, Second Edition and is reproduced with permission.