FRP tank Inspection 3

[SSood]

Hi Everyone

I would like to pursue my inquiry regarding the inspection of our double walled fiberglass underground storage tank system. We want to perform the integrity check for the tank and want to estimate how much longer we can safely use our tanks with little risk of a leak (what is the likely remaining life expectancy of the tank system?).

Can anyone please give the suggestion for an appropriate inspection protocol to use for checking the Tank.
Also please refer the codes and standards need to be followed for the same.

Thanks and Regards
Sood

 

[LittleInch]

See the guidance provided here

http://www.hse.gov.uk/pubns/guidance/pm75.pdf

In short, you need to look at the original design and to see whether the actual operating conditions and most importantly fluid, has changed over time. Any incidents of over pressure or external damage will form part of your assessment.

Also see this

http://www.hse.gov.uk/offshore/ageing/ageing-plant-summary-guide.pdf

P 23 deals with tanks and also refers to ISO 14692 pt 4 which is for GRP piping, but many of the same issues apply.

AFAIK, there are few, if any, NDT inspections which can be done other than visual and examination of records. A conversation with the original vendor, if still around, might point out issues that have occurred with other tanks of a similar design and use.

Clearly visual inspection is something you can do and also noting any visible weeping or de-lamination.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bimr]

Here is a link to an inspection test:

http://www.fiberglasstankandpipe.co...and-triple-wall-tanks-with-dry-annular-space/

 

[LittleInch]

Bimr

They look the real deal. They also have an inspection paper.

Still don't think they have much other than good visual inspection and performance testing like the annular test though.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bimr]

LittleInch

How would you do a visual on a buried test? Superman visual powers?

 

[LittleInch]

I think that's what the OP is looking for.... , but meant visual inspection of the surfaces exposed to the product or ones you could see - we have no idea of size of the tanks being referred to.

what I meant was that I haven't seen or heard of any inspection "tool" unlike various UT probes you get for steel that can give you any idea of future life.

The only thing I've come across requires a sample of the material (it was pipe I had) then mechanically test it to destruction and compare to the original material. Clearly with a tank that would then require a patch - not so good.

In theory FRP / GRP should last indefinitely if product is as designed and no damage has occurred.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Compositepro]

I thought the whole point of a double walled tank was to have leak sensors between the two walls. Then the tank can be used safely until a leak is detected.

 

[bimr]

The fact that a tank has a double wall does not eliminate the need for periodic inspection.

 

[SSood]

Thank You Gentlemen

Appreciate your help.

With Regards
Sood

 

[Pumprin]

My company actually used a vendor that specializes in fiberglass to conduct ultrasonic readings on a fiberglass pressure vessel a few weeks back to document/determine the remaining design strength of the resin from holding corrosive chemicals. Granted NDE methods for fiberglass doesn't seem as refined as for steel, but the vendor has documentation on comparing his ultrasonic readings to mechanically tested results.