rectangular opening for shell at API 650 Tank

[rudiawan .]

i am designing API 650 tank with diameter 40 meter, there is request from client to have opening for cleaning the sludge anytime, and should have an access for small heavy equipment, which estimate the size is 2 m width and 2.5 m hight.
is API 650 standard allow to make the opening for this size (rectangular size) ?




regards
rudiawan

 

[LittleInch]

You need to read section 5.7 carefully, but in general API 650 doesn't like big openings.

The general rule is that anything needs to be within one shell plate ( i/e/ doesn't cut across a vertical or horizontal weld and in general are considerably small than your dimensions. 1200 x 1200 looks to be the biggest in API 650.

All corners have a significant radius.

During tank repairs, contractors often cut out a larger section and then reweld, but not for regular access.

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

 

[JStephen]

That can be and has been done, but the opening will not comply with API-650.
Consider using a 48"x48" flush manway and whatever equipment will fit through that.
Or perhaps a large roof hatch and drop something in with a crane.

 

[LittleInch]

If you look at the photos of these the reinforcement pad is pretty large as is the reinforcement inside.

For a door that big (2m plus) it will be larger than you can transport on a normal truck....

Given that your client wants a water tank built to hydrocarbon standards (not much cheaper AWWA standard) and now wants a door big enough to drive a tractor through, do they really know what they are doing??

This is probably what he's thinking of, but is part of API 653 - Tank inspection and repair, not API 650.
See attachment I'll add it tomorrow.

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

 

[JStephen]

Just a side note- if the tank accessories, coatings, etc., are similar, an API tank would normally be cheaper than an AWWA tank, due to thinner plate, etc.

 

[HTURKAK]

NO!!!

Pls look API 653 ( Tank Inspection, Repair, Alteration,
and Reconstruction )

Rectangular opening having such a size 2 m width and 2.5 m height could be temporary opening . Pls search the forum for DOOR SHEET.

Definition of door sheet
A plate (or plates) cut from an existing tank shell to create a temporary access opening. After planned work is
completed, the door sheet(s) shall be reinstalled or replaced.



Good Luck




Use it up, wear it out;
Make it do, or do without.

NEW ENGLAND MAXIM

 

[LittleInch]

Attached is the information I was talking about.

You need some pretty big structures to stop the tank bending....

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

 

[LittleInch]

I stand corrected...

https://ui.adsabs.harvard.edu/abs/2023AIPC.2592e0004I/abstract

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

 

[Geoff13]

Attached is the information I was talking about.

You need some pretty big structures to stop the tank bending....

The attached presentation addresses temporary door sheet stiffening while the tank is out-of-service. As always, John does a nice job summarizing what's required. Love the solids removal photo on page 26.

However, if the OP's client meant something permanent, like a flush type clean out but larger than 48"x48" max size, then they are out of luck within API 650 rules. I suspect even if FEA could justify a custom solution, it would so expensive that cutting and re-welding a door sheet at each shutdown will look cheap.

 

[LittleInch]

The client definetly means a bolted flush type clean out door but agree with you about it being out of the scope of 650.

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