Sanitary Stainless Pressure Vessels and ASME Certification

[turb0tuned]

Hey All,

I'm designing an extraction process and have a few questions regarding ASME certification.

Why would one need ASME certification of the vessels vs. using "non-code" vessels?

Is it possible to get ASME U-stamped certification on a vessel that uses tri-clamp fittings as opposed to tank heads/pipe ends? See attached. Or are the only ASME code vessels those with semi-elliptical etc. tank heads/pipe ends? I know that there are certified vessels that utilize TC connections in combination with standard ASME tank heads/pipe ends but none that utilize a TC ferrule as the entire head.

If all vessels in the process were to be ASME U-code certified would each have its own code nameplate welded onto the vessel?

 

[JStephen]

The answers are "it depends".

In some areas, the state may require that pressure vessels be ASME vessels (but that's not the case everywhere). Or, insurance requirements or OSHA workplace rules might require it.

There are various exemptions to the ASME code: Piping, vessels less than 6" diameter, machinery parts, etc. You have sort of an oddball item there, and I'd take a good look to see if it fits one of those exemptions.

If the vessels are individual vessels, each would have its own nameplate. But you could have several bulby-looking things all connected that were all one "vessel", too.

Not sure about the triclamp- if it's some sort of conventional piping closure, I would think you could use it, just like you can use a flange and blind flange on the end of a vessel.

 

[turb0tuned]

Interesting! I will look into local regs to see if it is required that the vessels be certified as well as the exemption potential.

I'm not sure if Short Weld Tri-Clamp ferrules are a means to make a conventional piping closure. However, interesting point they do share a similarity with flange endings, and should be treated similarly. Anybody with experience using Tri-Clamp ferrules as piping closures? (see attached dwg) I could see them not being ASME certified because of the interesting load paths from the Tri-Clamps but I know they have pressure ratings themselves. This is a pretty low pressure application, looking at a MAWP of 150 psi and a MDMT of -20 F @ 150 psi.

Thanks JStephen!

 

[LittleEd]

Here's a good source to begin to find out what the jurisdictional requirements are in the state where the boiler or pressure vessel is located:

http://www.stateboilerlaws.com

 

[turb0tuned]

Thanks LittleEd!

 

[racookpe1978]

Any chance your pressure/temperature - even for food grade - got hot enough that somebody thinks a limit got exceeded?
Any chance "somebody" is simply assuming that "well we had better certify them, because all PV's get certified" ?

 

[turb0tuned]

Temps should stay very low, we are passively cooling, hottest they may see is a hot room temp @ ~90 deg f. Do you think this is "hot enough" to exceed a limit?

I think there could be chance "somebody" is assuming the latter. However, is this the correct train of thought? I would like to avoid the hoops and lead times of certification if possible.

 

[Compositepro]

You are using piping components so I think it is quite reasonable to call this piping. But then piping codes may apply.