Re: Re: CHEMICAL CLEANING FOR NEW PIPLEINES

Are the contractors that are doing the troubleshooting the same people that built it?

Occam's Razor: <a href="http://pespmc1.vub.ac.be/OCCAMRAZ.html">http://pespmc1.vub.ac.be/OCCAMRAZ.html</a>

<<Recently, during our plant start-up, some of our newly welded joints burst and break-off. To date, there had been no finding to the cause of these problems..
Some of the guys suggested that maybe the welded joint needs to undergo chemical cleaning to remove any unwanted contaminants that may cause flammabality such as oil and grease and other debris inside the pipelines.... The HAZ area inside the welding joint may also cause the welding joint to be weak and also stresses the need for chemical cleaning...

1. Does anyone knows why we need to do chemical cleaning for a new pipelines?
2. Does this chemical cleaning process also need to be done if we do some modification in the lines which involves a lot of welding procedure?
3. Is it possible that without chemical cleaning, there is a danger of explosions?>>
   • Original Message ----- From: "benj" <tinapabagoong@yahoo.com> To: <PipingDesign@yahoogroups.com> Sent: Saturday, August 02, 2003 7:30 AM Subject: [PipingDesign] Re: CHEMICAL CLEANING FOR NEW PIPLEINES

Let us say that the following has been performed. Hydrostatic Testing to B31 code requirement. NDE. No rejection noted/defect found
Qualified welding
Stress and flexibility analysis OK
Material is compatible with the service and traceable. Walkthrough/punchlist during cold functional test with emphasis at support location. OK
As-built confirm design layout.

What more is left. If its SS material, then one other possibility is buildup of biomounds resulting in UDC initiating MIC leading to failure of weld joints (and only weld joints – good weld joints). Possible Root cause – improper layup procedure. Such failure has been fairly documented by NIDI and NACE. What is interesting is that most reported failure happen during the commissioning and only weld joints has been attacked – one smart bug. The failure mode however is leak before break, which is not consistent with what has been posted – sudden bursting. Received on Sat Aug 02 07:53:00 2003