General
The gas phase filters shall be furnished as shown on the drawing HS-22-18. Each front access system shall be a 24" high, 24" wide and 20" deep and contain four HS-18 modules. The front access system shall be arranged in a filter bank sized as needed with an approach velocity not to exceed 500 fpm.

Construction
The front access system shall be constructed of 16 gauge steel with flush mitered and welded corners. Overall dimensions shall be maintainedat +0,-1/16" with a squareness tolerance within 1/8". They shall contain slide tracks for the mating modules and incorporate a gasketing to preclude air by-pass. They shall be powder coat painted.

Modules
Modules shall be constructed of 24 gauge perforated cold rolled steel with a powder coat of paint to insure corrosion resistance. The modules shall have a bed depth of no less than 1-1/4" and hold 0.64 cubic feet of gas phase media. The nominal dimensions of the modules shall be 6" high by 24" wide and 18" deep. Perforated steel portion shall be 24 gauge with 0.077" diameter holes on 7/64" staggered centers. Approximate void area of 41%.

Media
See the following specifications:
HS-22 with HS-18 Modules Media Specifications

Acceptable manufactures for the systems/modules/media are Hydrosil International Limited and approved equals.