Code? - To be or not to be ASME 2

[tjrush2000]

Rectangular vessel, 150 psi, 6" x 10" rectangular inside cross section.

code exemption rule - vessels having an inside diameter, width, height or cross sectional diagonal not exceeding 6 in., with no limitation on length.

it does not say - vessels having an inside diameter, width, height AND cross sectional diagonal not exceeding 6 in., with no limitation on length.

Is it Exempt?

 

[JimCasey]

Far in the deep recesses of my mind I remember that the code once stipulated vessels of 15 ft3 or larger as the threshhold of applicability. Last time I searched the code I could not find this stipulation.

Pragmaticlly, if the vessel fails is there a potential for property damage or personal injury? If so then assume the code applies and you will dodge a BIG potential for (personal) liability.

A rectangular tube with 150 psi in it WANTS to be a round tube. (This explains the dearth of square balloons). You will have huge stress concentration factors at the inside corners....that's where it will let go if it does. Robust external bracing is in order if you want it to remain rectangular with the pressure on the inside.

 

[djack77494]

I do not believe that the ASME pressure vessel code applies to rectangular vessels. Also, I have never in >30 years of practicing engineering seen a high pressure vessel that was not either cylindrical or spherical. As Jim Casey points out, it WANTS to become round. Please provide additional information for this most unusual application.
Doug.

 

[speco]

tjrush,

Actually, rectangular pressure vessels are quite common. The most obvious example of one is the rectangular box header normally found at each end of an air-cooled exchanger tube bundle. There is a whole section in the Code for calculating thicknesses, called Appendix 13.

Yes, rectangular boxes don't make good pressure vessels, unless they are very thick. So, they usually are. Especially when they are designed for pressures of, say 2000 psi.

I believe that your 6" X 10" cross-sectional vessel would normally require a Code stamp if it is designed for 15 PSIG or above. There are some minimum volumes in the code, but they are pretty small.

Regards,

Speco (

http://www.stoneprocess.com)

 

[jte]

tj-

When you state that the inside dimensions are 6" x 10" is that new or corroded? If it's new and you have any corrosion allowance, the design inside dimensions exceed 6" and you cannot use the 6" excemption in U-1(c)(2)(i).

Keep in mind, though, that even if you meet the excemption, you may still U stamp the vessel if you wish in accordance with U-1(c)(2) Based on the Committee’s consideration, the following classes of vessels are not included in the scope of this Division; however, any pressure vessel which meets all the applicable requirements of this Division may be stamped with the Code U Symbol:...

See also thread794-168265

jt

 

[MJCronin]

tj............

Suggest that you post on "Boiler & pressure vessel engineering" forum

You will get another group of opinions

-MJC

 

[Compositepro]

The code you quote says "or". Two of three factors exceed 6". So I read that the code applies.

 

[jte]

Compositepro-

You are interpreting the code incorrectly. If any inside dimension (diameter or height or width or diagonal) meets the 6" requirement it may be excluded from the scope. By your interpretation a #4 soccer ball would be a pressure vessel if I pump it up to 15.1 psig.

jt

 

[Compositepro]

That may be. I'm certainly not an expert on this code, but then a vessel that is 10 ft. x 10 ft. by 5" is exempt. That certainly doesn't make any sense.

 

[0707]

The ASME pressure vessel code Section VIII Division 1 has a section devoted to the design of rectangular tanks. It is in its Appendix 13.

For more i9nformation go to

design of rectangular pressure vessels
thread794-27937

luis marques