Tank Floating Roof Removal

[tcnv]

Are there published guidelines or recommended practices or procedures for how to remove an internal floating roof from an existing tank with a fixed roof? Also, should we be concerned with affecting structural integrity of the tank by removing the floating roof?

 

[JStephen]

API has a number of Recommended Practices, which include things like hot work and working under floating roofs, and those should be reviewed as needed. Generally, it wouldn't be any harder to remove a floating roof than to do other repairs in the tank.

The floating roof is not normally considered to add any stability to the tank itself, so there would not be an issue there. One thing to check is that without the floating roof limiting the fill depth, it may be possible to fill the tank to depths for which it was not designed.

Presumably, you have looked at operational and emissions aspects already.

 

[Duwe6]

Actual removal process is simple, but pricey
Empty and clean tank, and top & bottom of floater, and all floater compartments [if any].
Cut a 'Door Sheet' big enough to 'stab' a small crane through, about 7-ft high x 10-ft wide.
* CAREFULLY* burn drain holes in all tubular 'landing legs' that for the floater, and any tubular roof supports. Cl;ean up the effluent [if any]
Start cutting

Simple

 

[tcnv]

Thanks JStephen and Duwe6. Tank will be used again, so would rather not cut hole in side. Which API Stds or guidelines specifically should be reviewed?

 

[Duwe6]

Review API-653. Cutting out a "Door Sheet" entry is actually simple [for experienced tank builders] and is the industry standard for performing major work in a tank. This will not be a Do-it-Yourself project, sorry if I gave that impression. Get any reputable Tank Erection firm. With experience, this will be simple for them.

 

[MJCronin]

Why are you making this change and what kind of roof will the tank eventually have ?

 

[tcnv]

MJCronin- tank to be converted from oil storage to industrial wastewater storage. Floating roof ro be removed due to concerns with ice when converted to water storage. Tank already has a fixed roof in addition to internal floating roof.

 

[PieterStander]

I am not sure how far you are in this process, however it should be relatively simple to remove the old roof. Most IFR's are assembled inside the tank and use the existing inspection hatch in order for the roof pieces to be carried in. After cleaning and degassing, you should be able dis assemble the roof again, i guess the only major obstacle will be to roll the sheeting up again as small as possible.

We have recently installed 7 IFR's into existing tanks with out any cutting of the tank, everything fitted through the inspection hatches.

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