[labnetwork] Toxic Gases tubing

[mtkhbeis at gmail.com]

Kamal,

1. Not all jurisdictions require coax tubing by code. Unfortunately, my old university only wanted to pay for what was a code requirement and I had to fight for and pay for coax tubing. Double containment on toxic gasses is a best practice. As a lab owner/manager you should insist on it as secondary containment should not be viewed as a luxury. 

2. Both welded elbows and bending are acceptable practices. There are pros and cons to each approach. Bottom line is that you need to run quality control checks on both approaches and have assurance of line integrity. 

3. Heat tracing is chemical dependent. It is not based on the length of tubing. If you have a cold spot on an otherwise heated line, you will end up with condensation and problems. Vacuum jacketed tubing will obviously not conduct heat as efficiently; however, you are looking at steady state heating not transient heating. You should have heat trace coupled with insulation jackets from source to endpoint. 

4. You mentioned exhausted gas box at any point there is a mechanical connection (eg VCR interface, manifold, etc). This is a requirement. One point you didn’t mention is gas detection. You should be detecting at source, point of use ambient, and any location that has a mechanical connection. 

Best regards,

Dr. Michael Khbeis
(C) 443.254.5192

> On Sep 14, 2020, at 12:41 PM, Kamal Yadav <kamal.yadav at gmail.com> wrote:
> 
> 
> 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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