The elusive "+" rating. . .

[Wookie]

Captain, I really believe it is the stamp of approval of a slightly higher fill pressure and the perceived additional
liability that may come with the plus rating. I really don't think it is the math or the additional time. While I don't
agree with shops not giving this rating I can kind of understand their decision.

It has nothing to do with any dive shop, it has to do with whether the hydro facility understands how to test a scuba cylinder or not. Shops don't have anything to do with whether or not a cylinder gets a plus stamp.

 

[idive2]

It has nothing to do with any dive shop, it has to do with whether the hydro facility understands how to test a scuba cylinder or not. Shops don't have anything to do with whether or not a cylinder gets a plus stamp.

And you're convinced that it is because they do not know how rather than they prefer not to ?
By shops I was referring to the hydro facility.

 

[Wookie]

And you're convinced that it is because they do not know how rather than they prefer not to ?
By shops I was referring to the hydro facility.

It doesn't take any more time to do the proper procedure as it does to shortcut it. Why would a facility cheat you if it gains them nothing? I always ask the hydro facility if they have the special procedures for whatever SP tanks I'm giving them. I've never been turned down.

 

[captain]

You have to go back to why there is a plus to begin with. During World War II steel was in short supply for anything other than weapons of war. Tanks are steel but with ship building, needing gas overseas etc a way was need to move more gas in the same number of cylinders so it was determined that it was safe to overfill tank by 10% if they met the developed test specifications to do it.
Now the biggest use of cylinders is commercial gas, we can make as many new cylinder as needed and commercial gas is sold by the cubic foot. Users don't care how much is in the tank because they pay by the cubic foot and when it goes empty they grab another so there is no demand for plus rated tanks except in scuba and scuba is only a small part of their business. For 20 years after the war shop were familiar with it but as shop and people came and went the knowledge and need for it faded away.
Secondly commercial tanks may be filled 50 at a time so they are not going to worry if a tank or two in the batch has a plus, they fill all to the same pressure.

 

[halocline]

Captain, I really believe it is the stamp of approval of a slightly higher fill pressure and the perceived additional
liability that may come with the plus rating. I really don't think it is the math or the additional time. While I don't
agree with some shops not giving this rating I can kind of understand their decision.

The dive shop doesn't have anything to do with it, it's just a matter of hydro shops' ignorance or knowledge of these tanks. Remember, 90% of any hydro shop's business is fire extinguishers and welding tanks. Scuba tanks are way down the list. You'd be surprised how many of the hydro testers just don't know or don't care about 40 yr old scuba tanks.

OTOH, I have never had any sort of problem with a hydro tester once I actually spoke with him and showed him the PST REE document. Most of these guys are decent blue collar guys who want to do a good job, (not all, unfortunately!) in a field that surely pays fairly poorly. This is why I always bring my tanks directly to the hydro shop and, if I'm dealing with steel tanks, try to talk with the tester. I still don't have the plus rating on my kidde 72, but I did find one guy that invested a pretty fair amount of time in trying to locate the REE.

According to Luis, and I believe him, it is possible to measure tanks and calculate a REE with some precision, but that's getting into the engineering/design world, far beyond what can be probably expected of someone working in a hydro shop.

 

[elan]

Thanks God we are in Canada haha

 

[Wookie]

Thanks God we are in Canada haha

Why? TC allows a 10% overfill if the cylinder is marked with a "+" marking.....

 

[zider]

Is the hydro technician or the shop required to have additional training or certification to perform the plus rating step?

 

[Wookie]

Is the hydro technician or the shop required to have additional training or certification to perform the plus rating step?

No. They just have to follow the procedure. As has been stated, not all of them have the procedure, I always make sure the place I take my cylinders does before I drop them off...

Southern Indiana Scuba is only an hour south of you and they are a hydro facility. They specialize in scuba, and will not screw up your cylinders.

 

[zider]

No. They just have to follow the procedure. As has been stated, not all of them have the procedure, I always make sure the place I take my cylinders does before I drop them off...

Southern Indiana Scuba is only an hour south of you and they are a hydro facility. They specialize in scuba, and will not screw up your cylinders.

Thanks for the reply. Unfortunately that shop won't put a + rating back on if it was lost.