Question on plus (+) sign on Steel Tanks

[captain]

I find it interesting in this thread:
http://www.scubaboard.com/forums/ta...6-10-overfill-plus-rating-steel-lp-tanks.html

Post # 10

Go back and read post 24 of the same thread.

I think either the DOT representative didn't understand the question or the answer was misunderstood.
The hydro and + rating is good until the next hydro. At that time it could be hydroed but not + rated, not because it failed but simply because it was not checked to see if it qualified, and it could not be legally overfilled 10%.
This could be the case again at the third hydro but if at the fourth hydro it is is checked and qualifies for the + it can then be overfilled 10% again.
It is possible for a tank to fail to qualify for the + at a hydro and then qualify for the + at the next. But it must be + stamped after the latest hydro to legally be overfilled 10%

 

[Scott L]

I think you are misunderstanding the either the question or the answer.
The hydro and + rating is good until the next hydro. At that time it could be hydroed but not + rated, not because it failed but simply because it was not checked to see if it qualified, and it could not be legally overfilled 10%.
This could be the case again at the third hydro but if at the fourth hydro it is is checked and qualifies for the + it can then be overfilled 10% again.
It is possible for a tank to fail to qualify for the + at a hydro and then qualify for the + at the next. But it must be + stamped after the latest hydro to legally be overfilled 10%

Howard E does not miss understand much of anything you will find. He was speaking of DOT's rules and by inference indicates the diving industry is playing by their own moving target rules which are nonsencical...

 

[HowardE]

I think you are misunderstanding the either the question or the answer.

I was just quoting an old post, where they guy says he called the DOT.

 

[captain]

I was just quoting an old post, where they guy says he called the DOT.

By posting it I assumed you agreed with what was said in post 10 but in post 24 he corrects his misinterpertation of the CFR in post 10.
Just trying to keep from spreading misinformation, there already is enough of it where tanks are concerned.

 

[Dr Wu]

The + sign is used when you double the tanks. There should be a + sign on the right tank and a - on the left. When you attach the regulators make sure you don't touch them together or they will short out the gas in the tanks.

 

[WD8CDH]

There is no extra step that stresses the cylinder. It is tested to the exact same pressure as any hydro. The plus is derived from simply a mathamtical calculation that the shops don't have the ability to do because they do not have the magic number, the the REE limit (residual elastic expansion limit), or simply refuse to do it.

Newer steel cylinders sometimes has the REE stamped on the cylinders, older ones do not. If the REE is stamped on the cylinder there is no good reason not to + rate the cylinder if it qualifies.

If there is no REE, unfortunatly, it's not just a mathamatical calculation to get the plus. The hydro shop would also need both the internal volume of the tank and it's wall thickness to perform the math. Very few shops have the equipment to measure the wall thickness.

 

[WD8CDH]

The + sign is used when you double the tanks. There should be a + sign on the right tank and a - on the left. When you attach the regulators make sure you don't touch them together or they will short out the gas in the tanks.

When I set up doubles, I prefer to use tanks with the right tank marked Scotch and the left tank marked Soda. That way if the two regulators touch, it just mixes rather than shorting out the gas.

 

[HowardE]

By posting it I assumed you agreed with what was said in post 10 but in post 24 he corrects his misinterpertation of the CFR in post 10.
Just trying to keep from spreading misinformation, there already is enough of it where tanks are concerned.

My bad. I didn't read the whole thread.

http://www.scubaboard.com/forums/326364-post24.html

 

[scubafanatic]

I have had great difficulty getting a LDS to test for the + rating. It's my opinion they purposely avoid beleiving it is best not to overfill regardless of the rating. The extra step does further stress the cylinder as compared to the normal hydro giving them some arguement. If you want the + rating bypass the LDS and go straight to a hydro facility...

...it's interesting that you are reporting this from Florida of all places ! . .isn't Florida the home of the fabled...the mythical...the magical....CAVE FILL ??? ...heck, I often read how they routinely even fill party balloons to 5000 PSI down there.....

 

[Scott L]

By posting it I assumed you agreed with what was said in post 10 but in post 24 he corrects his misinterpertation of the CFR in post 10.
Just trying to keep from spreading misinformation, there already is enough of it where tanks are concerned.

Good clarification. It was mentioned earler in this thread and the one refrenced that LDS's must calculate wall thickness to gain the + rating. I know of no shop in S Florida that actually hydro's cylinders. They are transported to hydro facilities who perfrom the entire function. That is why I mentioned aerlier to go directly to a hydro facility which are refrenced on DOT's web-site to avoid the inevitable clash with the LDS....