How to design a floating roof 2

[carthago]

Does anyone has worked examples and background on how to design a floating roof for a API-650 tank ??
Well I know this is not entirely covered in API.
But this API talks about punctures and buoancy ??
What does this mean " design-wise".

I will hear from you guys!!

 

[JoeTank]

It looks like my earlier post did make it, so here it is again.

The expertise in floating roof design lies with the companies that build tanks. Anything you obtain from this newsgroup cannot possibly convey ompletely to you the complexity of the details. The tank builders will not share this expertise either as they have expended large sums of money over the years in order to develop that skill. There are no references that I have seen that do anything other that hint at the major features of design, but often lack info about the details that really matter.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[unclesyd]

I was just about to respond when SteveBraune{/b] posted his response.
Mine is essenitally the same.
I think the best approach for procuring a floating roof tank is to let a tank company design and build the tank while you watch and learn.

 

[rmw]

I take a different approach to that stated by Steve and Unclesyd.

Tank fabricators are like all fabricators who by definition have to make the cheapest thing possible that will do the job until the warranty expires. This is so that they can be competitive and win the bid.

This is not a knock, but a fact of life from the simplist fabricated item to the Space Shuttle.

In the absence of a good spec. (for the floating roof,) you are going to get no more than they have to do go get by.

Therefore, you sometimes want to look to those whose interest is not the initial tank bid, but the roof itself, often furnished as a replacement to the original floater supplied with the tank by the fabricator after a failure has occurred.

Here are a couple of links to sart with to familiarize yourself with the features and terminology. I'm not recommending them otherwise except that you can pick up some pointers about roofs by reading their stuff.

rmw

http://www.petrex.net/

http://www.ultraflote.com/

 

[JStephen]

RMW, I disagree with you on several counts.

There are several aspects of tank design that are seldom if ever tested by the tank warranty: Wind design, for overturning and blow-in; seismic design; snow loading on roofs; rainfall on floating roofs; notch toughness for lowest design temperature; internal design pressure, etc. In each case, these are loads that may or may not ever be reached in the lifetime of the tank, and are very unlikely to be reached in the warranty period. Yet, any reasonably conscientious tank company is going to design for these items.

I think you'll find that in dealing with the floating roof companies, they too are "fabricators" subject to the same market pressures that the tank companies are. This doesn't mean they don't make a good product, though. By all means, read their literature. And seems like I have seen some informative material from Baker Tank, HMT, and CBI/PDM among others. But generally, none of this material will give you any clue of how they actually go about designing a floating roof.

I might point out also that it is not at all uncommon to put an aluminum floating roof in a new tank as the original roof- they are not just replacements for steel roofs. Note also that the original question didn't specify whether the roof in question was internal or external- and for external roofs, there is no aluminum alternative.