The Final Word on + Ratings?

[Locus]

I've read various things about the significance of the + ratings on LP tanks. Many say that if a tank was + rated on its first hydro, then it should always be expected to get a 10% overfill. My LDS regularly gives me the overfill, but they mentioned something in passing about how my tanks don't necessarily qualify for it because they were only + rated on their first hydro, but not on any of their subsequent ones.

Which of these is correct? Assuming I'm entitled to the overfill, is there an official source for this that I can point to in the event that a shop won't fill my tanks above 2400psi? As a new diver, I'm greedy for every extra pound of pressure I can take on a dive, but it's not like I'm asking for a cave fill...

 

[Dr. Lecter]

In the US, the + rating is renewed, or not, after each hydrotesting contingent upon the REE value obtained in the test being within whatever the + rating REE value is for that make/model of tank. I have not idea how things are done up in America's Hat, however.

 

[halocline]

What Dr. Lecter said is true. The 'final word' unfortunately is that there are many incompetent shops, hydro facilities, and testers that don't know how to deal with scuba tanks, but have the ultimate say in how much air goes in your tank.

In the U.S., the + rating is only good for the most recent hydro test that has the + stamp. The most difficult part of getting it in the U.S. is finding a hydro shop that has a clue. You wouldn't believe the B.S. that gets spouted once you bring up the + rating at dive shops or hydro shops around here. It's really quite entertaining.

Good luck!

 

[KD8NPB]

I feel a lot safer filling a 40 year old steel tank than I do filling a 1980s aluminum tank.

At my shop:
6351 tanks = 2900-3000 fill
Old LP cylinders = 2500-2600 fill
Modern 3AL = 3200 fill

 

[idive2]

Make sure before your next hydro you ask the test station BEFORE your hydro if they do plus ratings.
If it leaves the hydro facility with a new date stamp and no plus stamp it may be five years before your next
chance for a plus rating. Once it is skipped I am told it is much harder to find someone to give it a plus
when the last hydro was not.

 

[halocline]

If it leaves the hydro facility with a new date stamp and no plus stamp it may be five years before your next
chance for a plus rating. Once it is skipped I am told it is much harder to find someone to give it a plus
when the last hydro was not.

You were told wrong, at least by the rules this is wrong. In fact, you could take the tank back to the hydro shop where it was last done, and they 'should' have recorded the total expansion of the tank at hydro pressure. If that number is lower than the REE number for that tank, the shop 'should' give the tank a + rating and stamp it as such. If the expansion exceeded the REE, then no + rating. Next hydro, whether it's in 5 years or 5 days, they simply go through the process again. I believe (I don't know this part for a fact) that there is some variance in the test procedure, and certainly it's possible that a tank could exceed REE on one test and not exceed it on the next.

What's truly depressing is that someone like me, just a recreational diver with a computer, some smart friends, and an interest in this topic, apparently knows the rules more accurately than many dive shops and hydro shops.

 

[Scared Silly]

Last winter I took some old PST LP72 in for hydro. The shop did not have REE but I did thanks to Certified Training Company - Hazmat Training Seminars. A month later they looked up the test numbers did the calcs and viola a shinny +.

 

[rjack321]

I have not idea how things are done up in America's Hat, however.

If you go out and buy a new 2400/2640+ rated tank in Canada they "should" be ignoring the plus since these tanks are all dual rated in metric for the North American market. Next to the TC mark it will say "182 bar" which is equal to 2640psi. I.e. they ignore pluses if the tank is TC approved in metric.

If you have a very old psi rated tank (pre-1970s), without a metric rating, its unlikely to be TC approved and is not legal in Canada.

Given that the OP is in Canada, their shop is filling in the wrong units

 

[Locus]

If you go out and buy a new 2400/2640+ rated tank in Canada they "should" be ignoring the plus since these tanks are all dual rated in metric for the North American market. Next to the TC mark it will say "182 bar" which is equal to 2640psi. I.e. they ignore pluses if the tank is TC approved in metric.

If you have a very old psi rated tank (pre-1970s), without a metric rating, its unlikely to be TC approved and is not legal in Canada.

Given that the OP is in Canada, their shop is filling in the wrong units

Hm, no mention of bar on them. Here are their markings:

SCUBAPRO DOT3AA 2400 85/9043 185 M8303 FABER 5/85 +

 

[Eric Sedletzky]

I've never been able to get a + rating on any of my old steel 72's.
The good part is I don't need to because my LDS will inadvertently fill them to 2500 or more on a regular basis.
I leave them and then ask them to please top them up once they cool down before I get back because I have a pet peeve about short fills. It works like magic.
I heard a steel 72 filled to 3000 makes it an 86, is that true?