Design & Planning
Materials
The silicone rubber used can tolerate temperatures between –60 °C and +200 °C and has a lifetime of up to 40 years under normal conditions. Many test reports testify that the mechanical properties of the silicone rubber barely change in response to extreme UV, weather and ozone loads. This silicone rubber is also halogen-free, dermatologically safe, and non-toxic. A radiation-proof version of silicone rubber was developed exclusively for use in nuclear power plants; this rubber still possesses sufficient elongation at rupture after 300 kGy of ionizing radiation. For use in nuclear facilities, the surfaces of the elastic seals made from this silicone rubber can demonstrably be decontaminated without any problems.
All rubber grades are subject to natural aging that reduces elasticity and raises Shore hardness. Under normal conditions, one can assume that the Shore hardness increases on average by 1° Shore A per year. This value may rise at higher temperatures. For this reason, we recommend that you inspect the Shore hardness at regular intervals and replace the expansion joints when the value reaches approximately 80° Shore A.
Assuming a Shore hardness of approximately 60° Shore A, the component lifetime will be 15 to 20 years. Wear and external influences such as UV radiation and ozone damage are also involved here.