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Re: Flat Heads-ASME Boiler Code Question

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> The Client has already confirmed 
>that the 10 psig shown on the drawing is incorrect.
Something is wrong, and I suggest you beware of someone pulling a fast 
one on you. You're right about the head dimensions for the detail you've 
described. 

>Does anyone know if you can have a flat head (one-piece) greater than 24" in 
>diameter?
Not for the construction you described. See UG-34 for acceptable details 
for any diameter.

>If not, what are reasonable methods of retrofit?.
The vessel can't legally be upgraded in any state with a pressure vessel 
law. The vessel carries a code plate if it is truly an ASME Code vessel. 
National Board repair rules allow repairs which will restore the vessel 
to the original design pressure, which will be on the Code plate. If you 
can't find the Code plate you don't have any idea what's there, and you 
shouldn't touch it. One psi doesn't sound like much but applied over a 5 
foot circle it makes a force of about a ton and a half--enough to spoil 
someone's whole afternoon. 

It sounds to me like your client doesn't really know what he has, so you 
should be real careful. Any mods to an ASME Code vessel have to be made 
according to the National Board repair Code, which, as I mentioned are 
not to be used to increase the operating pressure.


Christopher Wright P.E.    |"They couldn't hit an elephant from
chrisw(--nospam--at)skypoint.com        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)
http://www.skypoint.com/~chrisw