ASME Propane Tank California 86.5% Fixed Liquid Level Gauge?

[JohnMcNutt]

Folks, this question has been in my memory bank for a long time and don't know who to ask but this seems as good a place as any.

On aboveground tanks built for the California market, the fixed liquid level gauge (outage valve) seems to be most commonly set at 86.5%. Some manufacturers (AWT) build theirs at 80% anyway but not too manu.

I believe underground tanks have an even higher setting, maybe 89%? And MC330 truck tanks have some other setting, don't remember.

Additionally, California tanks usually have some additional guarding around the relief valve, and different placement of the liquid evac valve.

There is also a seldom-used allowance for a 275 psi relief valve setting in California.

Can anybody enlighten me as to what codes or standards apply and are used to make these changes from the "normal" tank?

 

[chicopee]

Get a copy (of any year) NFPA 57 which is the National Fire Code for LNG and that will explain the maximum fill level. I suppose that if you were either in the North or South pole the maximum fill level would be 100% as liquid propane could not vaporize at those very low temperatures until you had incorporated a vaporizer.

 

[JohnMcNutt]

NFPA 58, to be precise....

In Table 4.4.2.2(a) and surrounding, it seems to indicate that 40°F is a standard temperature that results in a final fill level of 80% for SG of .510 which would seem to correspond to 49 state tanks having that level preset.

However, California tanks are often (usually) built at 86.5% and that would correspond to a liquid temperature of between 85 and 90°F on the same column.

It gets warm here, but not warm enough that that could be considered a normal liquid temp.