[labnetwork] Toxic Gases tubing

Tue Sep 15 14:04:20 EDT 2020

We have the same at the University of Louisville.  Coax helps me sleep at night.

Cheers!

Julia Aebersold, Ph.D.
Manager, Micro/Nano Technology Center
University of Louisville
Shumaker Research Building, Room 233
2210 South Brook Street
Louisville, KY  40292
(502) 852-1572

http://louisville.edu/micronano/

From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Leif Steen Johansen
Sent: Monday, September 14, 2020 4:13 PM
To: Kamal Yadav <kamal.yadav at gmail.com>; labnetwork at mtl.mit.edu
Subject: Re: [labnetwork] Toxic Gases tubing

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Hello Kamal,

Like University of Michigan we also run all toxic and pyrophoric gases in coaxial pipes. The inner pipe is made of electro polished 316L stainless steel with a surface roughness of 0.25μm. All welding is orbital welding performed by certified welders using certified equipment. We allow our welders to bend the tubes with a dedicated tool. Some sites don’t allow this, since this theoretically could cause a larger surface roughness in the bends. Such sites buy pre-made bends that are welded onto the straight pipes.

The outer pipe of the coax line is monitored for gas leaks. We have two systems: One system constantly pumps on the outer pipe and monitors the pumped air for toxics. In the other type of system the outer pipe is pumped to vacuum, sealed off, and then monitored by a vacuum gauge. A coax monitor alarm (sensed gas or loss of vacuum in outer pipe) automatically shuts down the gas line, evacuates the building and calls the fire brigade.

All connections are of the VCR type and are placed inside a vented and gas monitored enclosure.

We have all the four gases you mention, and all of them are nasty in their own way, so please take good care of yourself.

Best regards,
Leif

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Leif Steen Johansen
Head of Operations, Ph.D.

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From: labnetwork-bounces at mtl.mit.edu<mailto:labnetwork-bounces at mtl.mit.edu> <labnetwork-bounces at mtl.mit.edu<mailto:labnetwork-bounces at mtl.mit.edu>> On Behalf Of Kamal Yadav
Sent: 14. september 2020 18:43
To: labnetwork at mtl.mit.edu<mailto:labnetwork at mtl.mit.edu>
Subject: [labnetwork] Toxic Gases tubing

Dear All,

We will be installing SS gas tubing for Cl2, BCl3, HBr, SiH4.

I have some experience in how industry does it, but wanted to know how different universities do this. From some prior posts, I got to know University of Michigan has co-axial tubing for all these gases and every connector location for these gases is exhausted as well at their facility

My queries are:
1. Is this how most of the Universities do it or there are places where these gases are in single tubing [non co-axial or double contained].
2. Also if you do orbital welding or just bending of the tubes?

I have been informed it is based on the fire code of the city or county, but it's not apparent from those documents.

Thanks for your help.

--
Thanks,
Kamal

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