The selection of the materials for pumps is at best a compromise between the cost of manufacturer and the anticipated maintenance cost. The selection of the most economical material for any particular service, requires the knowledge of not only the pump design and manufacture, but also of the erosion-corrosion properties of the material under consideration when subjected to the conditions actually encountered in the pump application. Many pump installations start out with a low service factor and through operating experience are gradually up-grated until an acceptable replacement schedule is achieved. For the more corrosive liquids greater modifications and replacement of the wetted parts will be necessary during the life of the pump.There is no substitute for experience in selecting materials for pump construction. Previous experience in handling a particular solution should be the main criterion in determining the optimal construction. Buyer shall determine the suitability of any product for its intended use and assume all risk in connection therewith.