A-A-1419 Filter Element, Air Conditioning (Viscous-Impingement And Dry Types, Replaceable) (Replaced By Ansi/Ashrea 52.1 And Ul900)This commercial item description covers standard dust-holding capacity, flat panel-type air-conditioning filters designed for arresting particulate matter in heating and ventilation systems in which the face valocity of the air stream approximately 300 feet per minute (fpm).

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A-A-1419D

3.4.3 Average arrestance. The average arrestance shall be not less than the applicable values specified in table I, when the filter is operated to the final resistance at 300 fpm face velocity.

3.4.4 Dust holding capacity. The minimum dust holding capacity shall be not less than the applicable values specified in table I. The capacity shall equal the amount of the test dust fed per unit net face area times its average arrestance. The dust holding capacity shall be obtained at 300 fpm face velocity. The results of table I shall be obtained at the maximum final pressure drop specified in 3.4.2.

TABLE I

Filter performance requirements
Thickness	Initial Resistance (inch wg)	Average Arrestance (%)	Dust holding capacity (grams per square foot)
1-inch	0.12	65	25
2-inch	0.15	75	40

3.5 Construction. The air filters shall be of the disposable panel type, viscous impingement or dry filter media type constructed with 90 degree corners. Media pad reinforcement in the form of grilles, retaining grids, fabric netting, or equivalent shall be installed on one or both faces of the filter as specified in the contract or purchase order. The media pad shall be attached to the frame and supported in such a manner that the media pad will not slump or otherwise be permanently displaced under the conditions of maximum air velocity (300 fpm) and filter resistance specified herein.

3.5.1 Frame. The frame shall be fabricated using wood-pulp products and treated to reduce moisture absorption. The frames shall be formed to provide positive support for the media pad and sufficient structural rigidity for normal handling, installation, and removal. The frame edges shall be parallel to within 3/16 inch.

3.5.2 Filter media. The filter media shall be of one continuous piece and composed of inorganic fibers suitable for its intended use. The media shall be fastened around the perimeter of the frame in such a manner as to prevent the media from being dislocated during normal handling and use.