Does external floating roof replacement require an hydrotest ?

[FrCivEng]

This is a 83 m diam x 20 m ht API 650 tank the external floating roof is to be dismantled and rebuilt with taking care about the bottom plate and no works within the critical zone; the rest of the tank is recent and was started up in May 2008 ; additionnaly a 2nd intermediate shell girder will be installed at 11 m ht
Do external floating roof replacement and additional girder installation require an hydrotest ?

 

[IFRs]

API 653 12.3.3.2 - Repair or alteration to a floating roof does not require a hydrotest.

 

[FrCivEng]

Thank you. In reality, we have to make a temporary opening in the tank shell to enter with equipment for EFR removal, which seems to be considered as a major repair according to API § 3.20, so I guess we have to perform the hydrotest ; what do you think about ?

 

[IFRs]

You may still avoid a hydro if the tank has tough steel, and you cut the door sheet above the corner weld a certain distance, and you perform extra NDE on the welds, and you use tough steel for any new shell steel, and you follow API 650 and 653, etc. Read API 653 section 12.3.2.

 

[786392]

Dear FrCivEng hello/Good Evening,
If recalled correctly you mentioned a double deck floating (sunken)roof damage, some 2 months back in these forums and also posted an image of mechanical excavator working inside to remove debris of damaged roof.

If this is the context then In all fairness I would go for Hydro on three accounts

1)It is safer/better for bottom plates damages revealing, if any and also for integrity assurance of the cut,re-welded shell segment test with water instead of stored material

2)Since making it again gas-free after crude Oil or whatever else of combustible flammable or volatile nature material storage for any repairs will become hell of a job

3)Even the floating roof's in-contact portions and its re-built structures as per design Bouyancy and free travel upto the top edge and back on the legs has to be ensured to avoide another failure consequently,you should appreciate.

On the above grounds I will never go further without Hydro test and floating roof's bouyancy/free travel assurance.

Best Regards
Qalander(Chem)