Penetrations are often made in metal roof decks in order to install sump pans, or drains.  According to the Steel Deck Institute when a 14 gauge sump pan is properly installed it will carry the load of the deck that it replaced and act as a small header to transfer loads into the adjacent sheets.

Place 1 1/2″ deep reinforcing channels in each rib at each side of opening. Attach flanges of sump pan to channels or Z reinforcing.

Sump pan attachment to channel or Z reinforcing

Channels may be used to reinforce the deck on both sides of the opening. Each end of the channels must rest on a primary support and fastened securely to the deck and sump pan.