Can i design shop fabricated tank on API 620

[inammanj123]

Hi,

I have api 620 water tank with 15 psig design pressure and 9.4 m dia. Client is looking for a way to limit site activities. One solution is to reduce the diameter to 6 m . In this case i did not find referece of shop fbricated tank in API 620. My question is can we do API 620 tank in shop, including hydro, which will be challenge to hold down the tank in shop with anchors.

thanks,
Inam

 

[MJCronin]

IMHO, there is nothing prohibiting shop construction of API650 or API620 tanks...

You will, of course, have to pay a lot of attention to lifting, rigging and transport of the tank.

IMHO, the 6 meter diameter seems a little large ... In the USA, we are constrained to ~ 5 meters + or - for most states

MJCronin
Sr. Process Engineer

 

[HTURKAK]

As per API 650 Appendix J (SHOP-ASSEMBLED STORAGE TANKS) the maximum diameter is 6m.

API 620 Section 1— Scope '.....this standard to cover large, field-assembled storage tanks of the type
described in 1.2 that contain petroleum intermediates....'

IMO, your tank is apparently small size and in case of mutual agreement of the Purchaser and the Manufacturer
,should be possible.

 

[inammanj123]

so it means API 620 can be done in shop, and still meet all requirements of API 620. like thickness formula, hydro testing, material allowable etc.
But i believe first we need to take confirmation from client, because it will be deviation of API 620 and also his specs.

Second case:
Keep the dimensions same as existing 9.4 m dia, but to limit site activities we can fabricate in two or three halves, and then weld all pieces on site. bottom plate+first shell course, second piece can be roof(with nozzles welded) and top shell course. Painting can be done in shop also. In this way anchors bolts can be placed on site on foundation and hydro test done on site.
I can understand that rolling shell course into 9.4 m dia and transporting on trailer is something questionable
what do you suggest.

thanks,
Inam

 

[JStephen]

My take- the tank can be shop-fabricated, but the pressure tests, which include anchor bolt testing, should be done in the field.

 

[inammanj123]

thanks got it !
if anyone has practically done a api 620 tank in shop, please do share your experience.

Regards,
Inam

 

[MJCronin]

imam...

There are only a certain number of tank fabricators who are able to transport your API-620 to the site.

Not every fabricator will transport this large tank to your site.... You do not have vast numbers of fabricators to chose from

What did they say when you called some of them ? .... What did they say about API-620 tanks shop fabricated ?

Please do share your experience ....

MJCronin
Sr. Process Engineer