A trench grate comprised of bar grating is often placed atop the drain system to create a stable walking surface that enables continued water or gas evacuation. Shuangyi is an industry-leading fabricator of trench grating products for commercial and industrial applications. Drainage Trench Grating Keeps Ground Dry. Steel bar grating is a widely used grating type. It can be used in the trench and drainage system as the trench and drainage cover to ensure the excellent drainage performance and secure the pedestrians safety. Trench grates cover trench drains to strain debris and safety and decoration to hardscape. We investigate trench grates materials including plastic, fiberglass, ductile iron, cast iron, stainless steel, galvanized steel, aluminum, and brass.