What is the design life of a rubber dam ? Some would say 25 to 30 years, others (mainly Chinese manufacturers/suppliers) would say 15 to 20 years yet some rubber dams fail after only several years of operation. Why the difference ? This week we visited a large run-of-the river hydropower plant in Norway where a rubber dam was installed in 1990. Dimensions of the air-inflated rubber dam are 1.7m high and 44.0m wide. The same rubber dam is still in operation today; almost 36 years later. How, why ? One of the main reasons is this rubber dam is operated in the best possible way; it is kept fully inflated most of the time and is only deflated in extreme flow conditions when all other gates have already been opened – estimated by the operators to be around once every two years. There is no upstream water level regulation that requires the rubber dam to be operated in a partially deflated position which is often the cause of many rubber dam failures. Secondly, the climate in Norway is favourable for rubber dams; UV radiation in northern regions is less damaging to the rubber than in hotter, more southern climates. Finally, the design and manufacturing was carried out by a reputable company with an abundance of experience, in this case Bridgestone. Key aspects for longevity; simplicity in design and operation, quality in manufacturing, long experience.
