I have always used a full fillet weld here for a 3/16" roof plate. Since
API650 is for atm. or low pressure., there should be no problems.
For a small diameter tank like this, it will be shop built and your greatest
loading will be from shipping. It will be shipped on its side so the roof
weld will see some large loads.
If you have some heavy roof loads or just want to verify the weld, you can
use the free-body method in API620.
Ron Hill, P.E.
HILL Consulting Engineering
Birmingham, Alabama USA
From: Ken Peoples [mailto:lvtakp(--nospam--at)yahoo.com]
Sent: Wednesday, June 21, 2000 8:48 AM
Subject: API 650 roof to shell joint
I have been asked to design a small tank (10' dia.) to
meet API 650. It seems to me that most things are
spelled out for me in the standard but I don't see
where the weld between the roof plate and the angle at
the top of the shell is specified. My detail is
Detail C of figure F-2. I see the information
regarding the weld having to not exceed 3/16" for a
frangible design (which I can't meet anyway because of
the area limitation), but I don't see where this weld
Thanks for your assistance
Ken Peoples, P. E.