1.1 This test method covers the determination of the modified fouling index (MFI) of water measured at constant pressure. This test can be used to indicate the fouling potential of reverse osmosis/nanofiltration (RO/NF) feed water due particulate matter and is applicable to low and high turbidity waters. Since the size, shape, and nature of particulate matter in water may vary, this test method is not an absolute measurement of the quantity of particulate matter.

1.2 This test method is not applicable for reagent-grade water Types I, II, and III of Specification D1193 or effluents from most reverse osmosis and ultra-filtration systems.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.