Suggested Division 15 Specifications Perforated Return Grille Model: 8R 8R • Steel Return filter grilles shall be TITUS Model 8R or 8RF for the sizes and mounting types as shown on the plans and outlet schedule. The face and border shall be constructed of perforated steel with 3/16-inch diameter holes on ¼ inch staggered centers to provide 51 percent free area. Outer borders shall be 1¼ inches wide. Corners shall be assembled with full penetration resistance welds with a reinforcing patch for extra strength. Screw holes shall be countersunk for a neat appearance. The grille finish shall be #26 white. The finish shall be an anodic acrylic paint, baked at 315° F for 30 minutes. The pencil hardness must be HB to H. The paint must pass a 100-hour ASTM B117 Corrosive Environments Salt Spray Test without creepage, blistering or deterioration of film. The paint must pass a 250-hour ASTM D870 Water Immersion Test. The paint must also pass the ASTM D2794 Reverse Impact Cracking Test with a 50-inch pound force applied. The manufacturer shall provide published performance data for the grille. The grille shall be tested in accordance with ANSI/ASHRAE Standard 70-1991.