PVHO Minimum Thickness

[kholasa]

Hi,

I'm a structural Engineer working on a design for PVHO...


What is the minimum thickness allowed for a Steel PVHO? Is there a workaround to go beyond this thickness? For example, A destructive testing or structural analysis.

Thanks

 

[JStephen]

I'll be curious if anyone's actually familiar with it.
I'd suggest to check the scope to make sure your application falls under it. And if weight is a concern, look at alternate materials.

 

[DriveMeNuts]

Do you mean ASME PVHO-1? Pressure Vessels for Human Occupancy?
I am very familiar with this spec.
Which country of use?

 

[kholasa]

Yes PVHO-1...Pressure vessel for Human Occupancy. Specifically a design for a Hyperbaric oxygen therapy cylindrical tank.

Country is United States.

 

[DriveMeNuts]

ASME PVHO-1 says that ASME VIII Div 1 or 2 be used to design the vessel. As most US staes require ASME U-stamped vessels, there are no loop holes. It has additional requirements for internal heads and does have some optional rules for external pressure design which may reduce some weight.
Your only option to reduce weight is to make the vessel div 2 (higher allowable stress).
In Europe, the vessel codes allow a higher allowable stress and therefore thinner shell (ASME PVHO is used to design the viewports only).
Most of PVHO-1 relates to the design of viewports.

 

[kholasa]

The PVHO states that for stiffened and un-stiffened cylinders, the minimum shell thickness excluding corrosion allowance shall not be less than 3/8". While the ASME DIV 2 says that the minimum thickness allowed regardless of the material is 0.0625".

I think that this answer the question, doesn't it?

 

[DriveMeNuts]

The 3/8" is for external pressure.
The 0.0625" is for internal pressure.
Comparing the two thicknesses is like comparing Apples and Oranges.
I think you need to pass this project over to a vessels engineer.