Question, vintage LP72 tank

[John C. Ratliff]

Pointless to search hydro facilities, you can do even better than that with a standard hydro. You just need a shop that understands those tanks.

I can get 3K from several shops as long as they know the background of these 72's and have a VIP that they can trust. Not so sure about ungalvanized, just don't know. But a 2800 fill seems entirely reasonable for that tank. ***Internet Advice***

72cuft at 10% overfill: So they are really 72-7.2cuft = 64.8cuft at rated pressure (2250).

64.8*(2800/2250) = 80.6cuft

Your math is good, but your advise is not so good. It is not a good idea, especially for these ol' tanks, to overfill them on purpose. There is a reason they don't have the "+" on the hydro, as these are old tanks, and must have more testing before the plus can be added to the hydro. There is quite an extensive discussion about overfilling these tanks here:

Overfilling LP Steel Tanks -- How bad is it?

SeaRat

 

[halocline]

There is a reason they don't have the "+" on the hydro, as these are old tanks, and must have more testing before the plus can be added to the hydro.
SeaRat

The only reason hydro test facilities don't give LP72s plus rating is they either are too ignorant or lazy to do so, or they don't have access to the REE number for the tank. There is no additional testing required for the plus rating beyond the standard hydro test. I would think you would know that given your level of experience. The age of the tank has nothing to do with it.

 

[rjack321]

Your math is good, but your advise is not so good. It is not a good idea, especially for these ol' tanks, to overfill them on purpose. There is a reason they don't have the "+" on the hydro, as these are old tanks, and must have more testing before the plus can be added to the hydro. There is quite an extensive discussion about overfilling these tanks here:

Overfilling LP Steel Tanks -- How bad is it?

SeaRat

I dont think an 11 yr old thread proves your point. LP72s with or without +s are not failing from 2800psi fills. They didnt in 2009 and they haven't gotten any worse since then.

 

[Luis H]

There is a reason they don't have the "+" on the hydro, as these are old tanks, and must have more testing before the plus can be added to the hydro.

SeaRat

Age affects humans; (with very few exceptions) it does not affect steel. I realize that some humans may think that just because we decay with age, everything else must decay as well, but that is not the case.

The only thing that age will do to a steel cylinder (or structure) is provide more opportunity for corrosion (rust) and other potential exposures to fire or other damage. All of this detrimental factors can be accounted for by inspection and testing.

Like @halocline mentioned, there is no extra testing needed for the + stamping. It uses the same data from the same hydro test, but it compares different numbers.

To obtain the number needed, the REE it requires just a little bit more effort and a little bit of knowledge.

All of my steel 72's are stamped with the + stamp. The hydro's were done by my LDS and I calculated and provided the REE numbers.

I can't remember ever seen a properly tested steel 72 fail hydro or fail the + stamp requirements. I didn't always checked for the + stamp requirements, but thinking back to the last 48 years and I can't remember a steel deciliter that passed without a large margin.



To calculate an accurate REE for any particular cylinder, it is best to measure the actual wall thickness of that cylinder. I did my cylinders by using ultrasound equipment at work (with the assistance of a technician, etc.). To do it again, I would just buy an ultrasound measuring device for about $82 at Amazon.

https://www.amazon.com/dp/B07QGZ94D...olid=3IKLA2O5BPLGF&psc=1&ref_=lv_ov_lig_dp_it

Once you have an average wall thickness (you want about 20 data points for the average), the calculations are relatively simple.

 

[John C. Ratliff]

Thanks Luis, I stand corrected.

The "+" rating doesn't allow for overfilling a stamped 2250 psig tank, with a "+" rating, to be filled to 3000+ psi though. 'Glad to hear that my steel cylinders will be around for longer than me!

SeaRat