Keep the drainage system free of debris with the trench drain grate. This ductile iron grate with longitudinal bar design is rated for NDS Class D loads when properly installed. The grate has an open surface area of 145.7 sq. in. per meter and impressive flow rate of 446.3 GPM. ADA compliant. Use two half-meter (19.69 in.) grates to cover one BG-FILCOTEN 200 8 in. trench drain. Iron grates are painted black to inhibit rust. Over time, it will form a protective iron-oxide patina.