Structural strength is provided by polyester resin and glass fibre reinforcement, which is finished internally with a smooth impervious isophthalic gel coat.
The gel coat finish on both the tank and lid ensures that harmful bacteria are not offered a surface on which to grow. Furthermore, all Sarena gel coats and colouring pigments are lead-free. To ensure water quality, the resin and gel coats are pigmented throughout to prevent the ingress of light. (Light entering a tank permits the organisms that are already present to multiply, which would contaminate the supply.)
In order to prevent osmosis (a condition whereby water is absorbed into the laminate), it is necessary to implement strict manufacturing controls during the production of water tanks and cisterns. At Sarena, we have implemented key elements into our manufacturing process in order to prevent osmosis. We ensure that the required amount of catalyst needed to cross-link and cure the polyester resin is measured precisely. We also ensure that a constant temperature is maintained throughout our manufacturing facility, as temperature is an essential factor in the correct curing of laminates.
Sarena tanks are given a full water test and results are recorded, ensuring that quality is followed throughout the design, production and finishing processes. Within the procedures documented in the Sarena EN ISO 9001 quality manual, full records are retained and each tank is clearly identified for traceability. Core materials, when used, are compatible with the laminate and are completely encapsulated within the structure.