This European Standard specifies the visual, dimensional, mechanical and durability characteristics of reinforced membranes made of plasticized poly(vinyl chloride) (PVC-P) sheets assembled together a polyester reinforcement, whose nominal thickness is greater than or equal to 1,5 mm, intended to be used to contribute to the leaktightness of inground swimming pools, implemented in situ. It also specifies the characteristics of the composition of the PVC-P used to produce the membranes. It applies specifically to reinforced membranes intended for use in swimming pools where the water temperature is less than or equal to 32 °C. If the membrane manufacturer permits a temperature of water continuously maintained above 32 °C, this document also applies.