What steel drawings does a loft conversion need?
A loft conversion typically needs steel beams to carry the new floor and the roof, and often steel around dormers - all sized by a structural engineer.
From those calcs I produce the setting-out and fabrication drawings your builder and fabricator work from, as part of the Building Control drawing set.
Fire safety and means of escape (Part B) also apply to lofts - that's handled through your architect/Building Control, separate from the steelwork drawings.
Structural sizing, spans and load calculations must be carried out by a qualified structural engineer. These pages help you plan the drawings you need - they are information only and are not structural engineering advice.