WHAT INSULATION THICKNESS HELPS TO ACHIEVE THE LIMITING U-VALUE FOR SWIMMING POOLS?
The insulation thickness needed to meet building regulations requirements for swimming pool basin U-values depends on a variety of factors. The nature of the swimming pool construction, together with the type of insulation used will have an affect on how the target U-value is achieved.
In addition, the calculation method for swimming pools – which is the same as for ground floor and basement constructions – features a number of variables. Understanding the effect of these variables can help to ensure that the correct insulation specification is chosen for a given project.
What variables affect the thickness of swimming pool insulation?
Heat loss calculations for swimming pool basins use the method given in BS EN ISO 13370, which is the same standard that applies to ground floor build-ups. This means swimming pool calculations also use the perimeter (P) and area (A) measurements for the pool (and specifically the P/A ratio), as well as the depth to which the pool structure extends into the ground.
Another factor that makes a difference (but which is not always clearly communicated in floor and basement calculations) is the soil type. Different ground conditions have their own thermal conductivity, and this can make a substantial difference to the level of insulation required in floors, basements and swimming pool basins.
Taking all of the above into account, along with the different ways there are of constructing swimming pools, there is no single solution that can be guaranteed to achieve a particular U-value on every project. Project-specific calculations are always advisable.
However, Polyfoam XPS has modelled different possible scenarios and looked at the effect of adjusting the variable involved. For the purposes of initial planning and creating outline specifications, extruded polystyrene (XPS) insulation in the region of 75mm thick could be used as a starting point.
Does a swimming pool require more insulation if it is outdoors?
One thing that is not a variable, and which doesn’t affect the rate of heat loss from a swimming pool basin, is whether the pool is located indoors or outdoors. Assuming the ground conditions are the same, the rate of heat loss to the ground is the same.
Being an indoor or outdoor pool changes the rate of heat loss from the water to the air, but that is beyond the scope of this guide. Advice on swimming pool cover specification should be sought to address that heat loss mechanism.
The Polyfoam XPS technical helpdesk carries out U-value calculations for ground floor and basement constructions, in accordance with BS EN ISO 13370:2017. Providing swimming pool basin U-value calculations is therefore well within the scope of our technical services.
To find out more or to discuss your project in detail, contact us.