Lintel for brick veneer

Try a W8 section with a bottom plate to support the veneer.

I would not use a loose lintel for a span over about 8 feet. End rotation of the lintel at the supports will create very high bearing stresses on the masonry at each end of the opening.

Two approaches we commonly use for longer spans:
1. Span a tube steel between columns, in the plane of the back-up wall, and size it for deflection, as well as combined bending and torsion. This can work well if there are columns adjacent to the opening on each side.
2. Hang the lintel from the floor or roof beam above. For hangers, consider steel channels the same depth as the backup wall, and space at about 4 feet. Use kickers to brace the hangers aganst wind. Design the overhead beam to limit dead load and live load deflection to a reasonable limit - maybe 3/8"? Have the Architect detail a vertical control joint in line with the upper corners of the opening, since the hanging lintel will deflect relative to the adjacent brick.

Nigel