Water pressure tanks with EPDM membrane

EPDM (ethylene propylene diene)

— the most popular material for membranes nowadays is both in water pressure tanks and in expansion tanks. This prevalence is due to a combination of reliability, practicality, safety and affordability. Thus, EPDM has high elasticity and a wide operating temperature range, tolerates an average of up to 100K cycles of stretching/compression within acceptable limits, does not react with oxygen and industrial alcohols and can be used in drinking water supply systems. However, in terms of overall strength and resistance to diffusion, this material is somewhat inferior to butyl rubber (see the relevant paragraph) — however, it is much cheaper.