ASTM F778-88(2014)

5.1 The air-flow resistance (pressure drop) of a filter is an important parameter that can assist in characterizing the physical make-up as well as the utility of a filter.

5.2 Therefore, flow characteristics of clean filter media can be used for quality control, product development, and basic research. It may be used by the producer of filter media to illustrate media type or to meet product specification and can be used by the consumer as a criterion for media selection.

5.3 These methods may also be used for acceptance testing.

5.4 For purposes of quality control, meeting product specification, or acceptance testing, a single-point flow regime on multiple samples is adequate. However, for design, development, and research, a multiple-point flow regime may be necessary.

1.1 The flow resistance of any fabricated filter device will depend on the flow resistance of the media used.

1.2 This standard offers procedures sufficient to determine the gas flow characteristics of flat specimens of media used in the filtration process. The methods are extended to include pleated specimens and bulk media as well.

1.3 In all cases, flow rates through the specimen are determined in accordance with procedures outlined in ASME “Fluid Meters.” The test fluid is air.

1.4 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems 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.