I am looking to replace a wooden i-beam in my basement with steal beam to be able to remove the posts.

the span i need is 21 feet.

above the beam is 2 bedrooms and a bathroom.

the roof above that is support on the outside wall, not down through the center of the house.

One side of the beam will sit on the exterior concrete wall, the other will be on a jack post. as the basement is broken up into two beams, 1 21 feet long, then a chimney, then another beam.
35'
--------------------------------
| |
| beam chimney beam |
|---------------[====]--------- 22'
| 21' 6' 8' |
| |
--------------------------------

A friend of mine did a similar thing, and used a W10x22 for this, i am Hoping to be able to go with a W8 or a W6 beam..

thoughts?

Thanks!