Dear Sir: Floating roof tanks are typically used for very large diameter tanks where a fixed roof construction becomes expensive to support and for products where vapor emissions become an issue. Hope this helps! David Hendrix The Hendrix Group Inc.

BHATTACHARYA, There is an excellenct discussion of floating vs. fixed roof designs in the text "Above Ground Storage Tanks" by Philip E. Myers Also, there is much discussion of the merits and problems of each particular tank type contained within this website: http://www.ast-forum.com/ As a common courtesy to us all, please complete this thread by letting us know about the particulars of your problem and the reasons for your selection MJC