aluminum vs. steel plate in corrosive atmosphere?

[kmg1983]

Currently we have 3 large crude oil storage tanks with internal floating roofs, each has a 3' x 3' inspection hatch on the outer roof in order to look for excess oil which may have escaped and is sitting on the floating roof. The hatch itself is carbon steel which is extremely heavy. Would there be any issue of converting the steel hatch to an aluminum hatch in order to cut down on the weight of it. Could I encounter any significant problems with having two dissimilar metals in a somewhat potentially corrosive atmosphere (H2S)?

 

[rustbuster]

The hatch may be designed to lift in the event of overpressure, I would check the original design before making any changes. If you do change, be sure to insulate the Al from the CS to prevent galvanic corrosion of the AL.

Most floating roofs are Al so the enviroment should be fine.

 

[kmg1983]

The hatch is simply there to allow a means of looking in and inspecting the floating roof. Should I be concerned with anything else?