nozzle calc dried compressed air

[CNewman]

I'm trying to do a nozzle calculation for a vessel that uses dried compressed air (non-corrosive service). This vessel is being sold in tandem with an air drying system.

UG-16 states that materials for use with 'compressed air service' should use a min material thickness of 3/32" (instead of the default 1/16") if the material is listed on Table UCS-23, which this one is. For the purposes of this section, does 'dried compressed air' count as 'compressed air'?

My question is about the min thickness of the nozzle wall. The calculated thickness is less than 1/16", and I need to know if I use the calculated value, 1/16", or 3/32". I'm asking because there are sections (i.e. UG-46) where dried air is specifically mentioned as not equivalent, because plain pressurized air is considered corrosive (water condenses out).

 

[vesselfab]

std wt plus corrosion allowance
or
required thickness of shell plus corrosion allowance

lesser of the two

 

[CNewman]

Just to clarify, if the calculated value min t = .06", and the required material thickness is 3/32", I use t = .06 for the reinforcement calculation.

Thanks.

 

[GenB]

any ansi nozzle is acceptable depending on the pressure of the equipment.
I don't think compressed air has a difference if you dry the air.- what if the dryer fails...
you design to the most worst condition or expected service.
in this case compressed air.

 

[gr2vessels]

CNewman,
The intent of the code is to set a minimum thickness of the air receiver to 3/32", exclusive of corrosion allowance and irrespective of wet or dry compressed air. It is up to you and your customer to add a corrosion allowance or not, depending on the application (wet or dry), internal painting, expected service life, etc.
The UG-46 makes optional the inspection opening on the dry compressed air receiver, not the wall thickness.
Cheers,
gr2vessels