oil and vapour come out from roof legs 1

[mustafa2014]

Dear all,

our tanks is a floating roof double deck dim.88m.The problem is that oil with vapor come out from some legs. I have checked the pontoons and are okay.
As far as I know if there is a vapor should come out from vents. you will find attached some pics.

 

[mustafa2014]

Dear IFRs,
Thank for your kind reply.

in another case we have a single roof deck damaged completely because the pontoons get punctures although the tank is only 10 years old.

Any way, I have proposed the DOME ALUMINUM with AIFR because our product is light product "condensate". My company agree , but I have still some concerns below:-

1- Frangible roof is not possible . The frangible roof specified by API 650 is a valuable explosion
and over pressure protection, it is not known how the Aluminum domed roof will perform under
similar over pressure situations.

2-The quality of the Aluminum dome weather-tight design will vary by manufacturer.

3-Aluminum's lower resistance to turbulence (lower mass) shall be considered on tank stability
checking.

4-Modification to the existing facilities such like as structural , mechanical, piping, instrumentation &
controls, fire fighting , and fire and gas detection systems are a big concern in this retrofit project.

5-Galvanic corrosion which is the most common cause for Aluminum corrosion is a very real
concern in and near to coastal applications. Higher initial cost when compare to steel EFRT.


Please your help

 

[IFRs]

1- Frangible roof is not possible .
This is not an issue because the circulation vent area that is present with any internal floating roof is enough to provide emergency venting.

2-The quality of the Aluminum dome weather-tight design will vary by manufacturer.
This is an issue - buy a quality dome roof, not the least expensive one.

3-Aluminum's lower resistance to turbulence (lower mass) shall be considered on tank stability
checking.
This is true but tank stability can be checked mathematically. If the tank was stable as an open-top tank then adding a dome will not change that. If the tank currently has a steel cone roof, why change to a dome?

4-Modification to the existing facilities such like as structural , mechanical, piping, instrumentation &
controls, fire fighting , and fire and gas detection systems are a big concern in this retrofit project.
I think the only issue will be fire fighting - the aluminum IFR may require full-surface foam protection per NFPA or whatever code your live by in your country. Piping should not change, detection systems may change (but can usually be improved). You may find that you have more capacity because the AIFR can have a lower profile ( certain vendors and especially their seals ).

5-Galvanic corrosion which is the most common cause for Aluminum corrosion is a very real
concern in and near to coastal applications. Higher initial cost when compare to steel EFRT.
A marine environment can be an issue but galvanic should not because the steel tank to dome interface is via Teflon bearing pads under the dome structural connections ( or should be ). The internal floating roof should not care but you can get marine type alloys ( 52xx series ) from some vendors.

If you have the budget, you may want to consider upgrading to a more expensive aluminum floating roof for strength, emissions and safety reasons. At least one is made that is designed for the same load as a steel floating roof and several that are nearly as good.

Note: Among other things, I have worked with aluminum floating roof companies for 37 years and am not unbiased.

 

[mustafa2014]

Dear IFRs,

Regarding point Nr.3 our existing tank is single deck floating external roof.

Point 4 we are following NFPA THE VENDOR WILL UPGRADE AS NFPA 11.

regarding the expensive aluminum floating roof for strength, we have receive an offer from CTS , Is this company okay with domes with AIFR (is there any other best company)??Moreover, could you send me any reference regarding ALLOY(52xx) for more information

I have PICTERS THE OFFER could you send me your mail address please to pass to you all things

 

[IFRs]

A single deck floating roof does not normally have pontoons - could it be a bulkhead or pontoon style?

NFPA-11 allows only a limited few type of IFRs to have rim protection, all others require full-surface foam. You may already have full-surface protection, it is worth finding out.

For info on 5052 alloy, see these and many others:

http://www.metalsuppliersonline.com/Research/Property/metals/472.asp

http://en.wikipedia.org/wiki/Aluminium_alloy#Marine_alloys

It would be better to go off-line to discus specific dome vendor's products.

There is only one aluminum internal floating roof that I know of that is designed for the same loads as a steel floating roof, there are some that are lower priced but still high quality and there are still more that are average quality and even lower priced. As is common throughout the world, to some extent you get what you pay for...

Click my name, there should be more information about me there.