LPG ullage requirement for Pressure Vessels

[napster385]

Hi everyone,

Is there any code requirements for ullage of LPG storage in pressure vessels? Is above 85% liquid LPG volume content for a aboveground pressure vessel permitted?

Thanks

 

[chicopee]

No, I have not read any code that allow for ullage in a LPG tank. I suppose that if the tank was positioned in the North or South pole(where the temperatures, regardless of the season, are too low to generate useful vapor pressures) you could fill the tank to its volume but then you'll need a preheater to warm up the liquid propane into a gaseous state. Ullage in a LPG tank is to allow for thermal expansion that one may see during changing weather conditions.

 

[GenB]

Better consult local,jurisdictional Rules not ASME Code. I heard of tanks bloawn up in the summer due to overfilling and expansion. A suitable PRV may be the answer.

 

[saplanti]

I have mechanically designed a LPG spherical storage vessel even with 5% of ullage. I am not sure about your background, I think the ullage of storage vessel should come from the process department/client since the process is their responsibility.

Hope it helps.

 

[dcasto]

http://chrysmetal.com/itemimages/314701.jpg

Look at this picture of a level gauge on a propane tank, this is the propane accepted standard for outage based on temperature.