Polymer batch numbers are linked to the manufacturers material certificate Discrete batches of polymer are not mixed. The bach number of the polymer used is recorded on the moulding log sheet against a specific mould reference. FPA lined valve testing, The PFA we use meets the requirements of ASTM D3307 Type 2. They are also specified as having a restricted melt flow index not exceeding 3 grammes in 10 miniutes. We extensively use our own in house melt flow indexing test equiment to ensure the PFA PFA lined butterfly valve complies to our strict quality controls.