Nothing at all in many cases.  Silicone hose and tube is widely and successfully used to transfer chemicals, foodstuffs, and other fluids in a wide range of applications but sometimes problems occur, because there are a number of specific disadvantages which render silicone hose unsuitable in some applications.

Chemical resistance;  Although silicone rubber hose has excellent chemical resistance to nearly all foodstuffs and biological fluids, there are many chemicals, solvents, fuels and oils which interact with silicone rubber, swelling or degrading the rubber and/or contaminating the fluid being transferred.

Steam resistance; The resistance to steam, especially at steam pressures above 50 psi (3 bar) is limited, as the silicone rubber will degrade with increasing exposure. This represents a problem in applications where steam sterilization is applied.

Fortunately, there are now alternative products which will solve these problems, yet continue to offer the other advantages which silicone hose provides.
PHARMALINE and PHARMALEX hose products from Aflex Hose include a unique and patented super-flexible PTFE hose liner tube, replacing the silicone rubber liner used in conventional silicone hose construction. The external cover is platinum cured silicone rubber, and the Pharmaline also includes an SS wire braid between liner and cover.

Pharmaline and Pharmalex can do everything that a silicone rubber hose and tube can do, and much more. They meet USP class 6, are made from FDA approved materials, and meet all the other specification requirements, but have much better steam resistance, and almost universal chemical resistance to transferred fluids due to the PTFE liner.

So, if you have a problem with your silicone hose, or would like a product which provides greater reliability and a longer service life, read more about Pharmaline and Pharmalex.

And if you would then like to receive a short free of charge sample of Pharmaline or Pharmalex, please send your request to Holland Applied Technologies.
Pharmaline Specifications