Tank roof repair using BELZONA 1

[jrafael95]

Dear colleagues,
Could someone tell me where can I find in API 650 or 653 about tank roof repair using cold work? (for example, BELZONA)

 

[IFRs]

You won't find that in API 650 (new tanks, not repairs) or 653 (which is all about permanent repairs).

 

[jrafael95]

@IFRs, thank you for your answer.
Do you know where I can find any normative recommendation for this type of repair?

 

[IFRs]

The only cold repair I've done was to cold cut holes and make bolt-on metal patch plates with gaskets and sealant. Temporary until a real repair could be done. Can you share more info?

 

[jrafael95]

@IRFs,
I am studying an issue for my client,

The issue:
My client owns hundreds (literally) of API 650 vertical storage tanks at various fuel terminals nation-wide (not USA!).

I need to make several step-by-step procedures (according to API) to standarize the maintenance of these tanks. They want one for cold repair using belzona in their roofs (as premise, they are all fixed conical-roof).

But I didn't find any API standard that allows this nature of repair, but I know that a lot of companies do this type of service.

The best refference I found is this attached file:

 

[HTURKAK]

Dear jrafael95 (Mechanical

API 650,620,2000.. are Construction Standards.
API 653,510,570 ..Inspection standards.
You shall look to Recommended Practices (RP). Regarding the roof repair,

API RECOMMENDED PRACTICE 575 10.3 Special Repair Methods states:
'Leaks in roofs can be repaired by soft patches that do not involve cutting, welding, riveting, or bolting of the steel. Soft patches can be made from a variety of materials, including rubber, neoprene, glass cloth, asphalt, and mastic or epoxy sealing materials; the choice depends on the contents of the tank and the service conditions. The patching is applied in much the same manner as similar patching would be applied to the roof of a building. The patches may be applied when the tank is in service, if proper safety practices are followed. Figure 67 and Figure 68 show a patch and a complete coating, respectively.'


NEW ENGLAND MAXIM Quote 'Use it up, wear it out; Make it do, or do without. '

Good Luck


Good Luck..

 

[IFRs]

Will you limit the hole size you going to allow to be patched?
At what point to you say patching is not OK?
Will you patch in service?
How will you know that the rest of the roof is safe to walk on, and for how long?
Do you need to restrict the tank's use after making a soft patch, for instance:
can it be walked on for normal operations ( gauging, inspection, etc )
will it be good for all normal loads ( wind, snow, etc )
will it be good for all operational loads ( pressure and vacuum )
will it be good for emergency conditions such as fire in a nearby tank
what time frame will it be good for
how will future inspections be done

 

[jrafael95]

@HTURKAK:
Thanks for the answer! I will get this API RP right now

@IFRs:
Thanks for the answer too

Will you limit the hole size you going to allow to be patched?
My client didn't say anything about this,so , at this first moment, I'll recommend this type of repair for holes that do not affect the strenght of the roof.

At what point to you say patching is not OK?
Honestly, I need to study more about this type of repair before giving a technical opinion

Will you patch in service?
Yes.

Do you need to restrict the tank's use after making a soft patch, for instance
No.

My client has it's own inspection program and I don't have any info about how they would inspect a tank with it's roof repaired with belzona.

 

[Dhurjati Sen]

Well your client is going for a very unsafe and unscientific practice.

Unsafe as the personnel applying belzona (or other people who would later visit the tank roof) are at risk as the perforated roof plates need to be replaced.

Unscientific as the hydro-carbon vapours could eat away the belzona in days or months which is not properly known.

These are nothing but cost cutting measures in uncertain times. Try to stay away from such non-sense.

DHURJATI SEN
Kolkata, India

 

[jrafael95]

@Dhujarti Sen, thanks for your answer.

I'm worried about this practice too. I'll have a meeting with my client and I'll alert him about this practice.

If you have some good info about this, could you send to me?

 

[Dhurjati Sen]

Google the following:

Durapol UHT

http://www.sealtec.co.il/index.asp

They are experts and you may contact them.

Application of Belzona 1391 was tried in a plant in the middle east, but it did not last for long.

Standard Disclaimer: I am in no way connected to M/s Sealtec and strongly believe that complete or partial replacement of the perforated roof is the most appropriate solution.

DHURJATI SEN
Kolkata, India