Re: MIC on Potable Water Piping.

From: <geoff.stone@lendlease.com.au>
Date: Tue May 29 2001 - 07:13:00 EDT

Suggest you use ABS pipe for such an application. Its easier to install and resistant to such attacks.

I have experienced such a microbe eating its way out of aluminium tanks in fighter jets. We ahd to build the Avtur installation with aluminium pipe and 316 ss elbows. each sch 10s fiiting had to be internally profile so the whole pipe would drain. The microbe lived in small quantities of water in the Avtur. Lines were sloped so no water was left in the system.

Nalco love to sell you a solution. Normally a very high priced chemical.

"SARE, RALPH H." <SARERH@YANPET.SABIC.com> on 29/05/2001 21:02:42

Please respond to <a href="/group/PipingDesign/post?postID=dNChKHgasWX0MUbgvnmPVr1sDGQ9GUtEB6wBKMM6TXcu_VqVxWWeBfiIxeX1oIHswfVEHShZOTw9Kg4bTd_Kz0loNw">PipingDesign@yahoogroups.com</a>

To: <a href="/group/PipingDesign/post?postID=dNChKHgasWX0MUbgvnmPVr1sDGQ9GUtEB6wBKMM6TXcu_VqVxWWeBfiIxeX1oIHswfVEHShZOTw9Kg4bTd_Kz0loNw">PipingDesign@yahoogroups.com</a> cc:

Subject: [PipingDesign] MIC on Potable Water Piping.

Contractor has just completed the installion of 6" 304L ss potable water piping. After 3 months, 50% of the 300 welding joints has been observed leaking . Pitting attack has so far been confined only at the weld joints.. No failure was observed in the process ss lines.

Expert from Nalco has been called to assist and identify the cause of pitting and weld failure. Nalco says the cause is MIC. No it does not stand for microphone but rather to microbiologically influenced corrosion caused by anaerobic acid producing bacteria.

System has been treated with shock dosage of chlorine, but what do you know. Damn MIC can survive in chlorinated water. Its source unknown.

What suprises us is how come this bugger only loves to eat a weld joint ? Our lab has also indincated that this bacteria is no health hazard - system is potable water. Meaning its ok to drink the wtaer because the MIC only attacks a ss weld joint (the bugger must have hated a human intestine)?

Anybody has any experience on this MIC?

Metallurgist suggestion is top apply a leeve around the weld joint using AL-6XN or wrap with fiberglass or compeltely replaced it with galvainzed cs pipe.

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[Non-text portions of this message have been removed] Received on Tue May 29 07:13:00 2001