The reinf. pad to vessel shell weld (mostly) broke.
A pinhole leak in nozzle weld is unlikely. Generally the nozzle will be welded from both sides of shell. Also, DP test of welds (after root pass on one side) is rigorously followed (even when we are not around. After satisfactory completion of nozzle welding only, the doubler plate will be fitted & welded.
Regarding the dryness part, any person working in the field knows the hazards, even when not conversant with the codes.
Regards
-----Original Message-----
From: <a href="/group/PipingDesign/post?postID=za76YwvVIwbBpo_xXN9ROeJ07ZtT_QNVd_H7D4o7QkSFUrfaRdZH6talkuoA5nU5pyykgeZbaatmzVzvtOdldBes--bUyl0">PipingDesign@yahoogroups.com</a>
[mailto:PipingDesign@yahoogroups.com]On Behalf Of Christopher Wright
Sent: Thursday, September 15, 2005 8:58 PM
To: <a href="/group/PipingDesign/post?postID=za76YwvVIwbBpo_xXN9ROeJ07ZtT_QNVd_H7D4o7QkSFUrfaRdZH6talkuoA5nU5pyykgeZbaatmzVzvtOdldBes--bUyl0">PipingDesign@yahoogroups.com</a>
Subject: Re: [PipingDesign] Re: Reinforcement Pad Weep hole
On Sep 15, 2005, at 12:31 AM, CHAKRABORTYP2@iocl.co.in wrote:
> But that does not explain the bulging of reinf. pad with
> some sort of explosion, neither it solves the inward
> movement of shell plates in that location after the
> explosion.
You're right, it doesn't. Which welds broke on your vessel? Was the
construction a formed doubler plate fitted around a nozzle or a pipe
saddle?
I expect there's a clue in the Section VIII sub-paragraph I quoted--possibly a pinhole leak in the nozzle attachment weld. I don't think they'd have such a strong a requirement for a tell-tale hole nor a mention of possible leaky nozzle welds if it hadn't happened before. I confess that provision had completely slipped my mind when I replied to the post. I'm not all that fond of doubler plates anyway since they're difficult to form and fit properly, and the open tell-tale is an invitation to corrosion problems. Pipe saddles are different, but the attachment welds have to be 100% sound or you will get leakage into the space between the saddle flange and the vessel wall.
You might also want to note that Part UW of section VIII requires that parts to be welded must be dry--no exemptions for Assam.
Christopher Wright P.E. |"They couldn't hit an elephant at <a href="/group/PipingDesign/post?postID=kwfMQpuC3GAoEIO0oBdXZ0ZepI7wQXQVfpiM-L0RYoqLZPGBojJ2EJxICeR3cxHUZqlE-WPFNjF2Gg">chrisw@skypoint.com</a> | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania1864)
Yahoo! Groups Links Received on Fri Sep 16 00:37:00 2005
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