Cleanroom Fittings

I am not familar with clean rooms but my concern is for running a deadly gas inside a closed building. We had to do this for labs in chemical plants and we used all brass pipe or stainless. The brass was socket weld fittings, silver soldered and the stainless was welded. Our concern developed from the fact that the building was a safe haven for protection from violent events occuring outside, which could impact the piping systems entering the building. We did not want the gas escaping inside our refuge. soldered and welded joints are much more durable and leak free.

Thanks.

The pipelines that we are going to run are for Nitrogen & CDA, so they're not deadly. Only concern is that the production requires high quality (contamination free) gasses and I was wondering whether the brass fittings would pose any contamination issues.

There would more contamination from the line, more than the fitting. You would have to see if the gases might interact with brass. I am assuming your lines are brass since you want to use brass fittings.

<The pipelines that we are going to run are for Nitrogen & CDA, so they're not deadly> Must disagree as not deadly, attest my neighbor and his two employees, that are no longer with us due to nitrogen. Each trying to rescue the other. Just in case you are not aware--- our breathing in and out is triggered by a build up of co2 in our lungs, co2 present-- breathe, no co2 =don't breathe. Excess N2 displaces the co2 = no trigger- no breathe- no o2 going in. The o2 that was breathed on the last breath has transfered from high concentration (lungs) to low concentration(blood vessels) now N2 has displaced O2 in the lungs, O2 flows back from blood to lungs( high to low) blood is suppling brain first thing, heart pumps blood with no o2 - brain go limp no co2 no more breathing === no life. 1 breath is all it takes.

Second case of death = An outside tank was made ready to be cleaned the day before, Manhole opened. N2 purge was supposed to be shut off, it wasn't. The tank was inside a containment wall 42" high with no openings. The next morning an operator with gas monitor( hydrocarbon, H2s, and low O2 detect) in his hand with the sample hose looped over his sholder behind his neck, entered the dike wall via a ladder for the purpose. The weather was no wind, 70 degrees F. The investigation showed that the dike wall had filled with N2 that had come from the tank and being cooler than the air had setteled, no wind to stir it, the "sniffer hose was high enough being over his sholder that it was above the walls height. There was a wrench left on the floor the day before that he bent to pick up. He never straightened back up and died. His low o2 monitor was in alarm. Be very careful.

This link should provide some ammo.

www.csb.gov/safety_publications/docs/SB-Nitrogen-6-11-03.pdf

Thank You

Stick with stainless steel. In the US all clean rooms use stainless steel. Stainless steel tubing and the fittings can be either welded or high reliability compression fittings like Swagelok, Parker, Tylok or similar, usually two part ferrule. Welded is superior but significantly more expensive. Good luck!

Ability@ameritech.net

In the cleanrooms that I have worked in everything had to be SS SC-11 cleaned. That was for medical device manufacturing though, it may be different for your specifications.

Good morning, Alvin,

I'd tend to avoid brass fittings due to the possible contamination that you speak of, but also due to the potential for particle contamination of your process gases and the process lines/chambers inside the equipment. If you review the materials of construction inside your equipment or contact the manufacturers, that'll give you a good idea as to the MOC of the supply lines.

And, as always, check regulations and codes. They may have requirements and specifications that make the choice a moot point. IE: they may make the decision for you :)

Hope this helps!

Thanks for all the replies. To me the SS parts would be easier to clean but I still can't imagine how it would contaminate the process gasses. Is it because of the material itself or the surface finish of the different materials.

I'll also take it in mind to be careful with N2. Thanks a lot.