+ Hydroing old steel 72s

[aquaregia]

I need a hydro on two of my 72s. The local places I've tried to use won't + rate any of my 72s "automatically". I sent them in once with instructions to test for + and got them back without a + or any explanation (I'd be fine with it not passing, but I suspect they didn't even try).

Is there a procedure that I can use to 'encourage' a place to test? Can I get ahold of the REE numbers based on serial number or something? Does it help to go straight to the hydro place instead of an LDS? How can I find hydro places?

Cheers.

 

[Jimmer]

Send a PM to Luis H, I believe he has the REE # for the old PST 2250psi 72's. He might be able to help you out.

Jim

 

[captain]

The REE for PST 72 is 58.4 cc's. If they don't believe you you can direct them here.

http://www.ctcseminars.com/files/technical/PST REE values.pdf

Other tanks such as Norris or Walter Kidde may be slightly different but so far no one has found any documents from either to verify what they are. Luis is working on doing the necessary wall thickness measurements to calculate the REE for Norris tanks.

 

[Bob DBF]

Are you going to the hydro facility and talking to the operator? If you send them in through an LDS the note or instructions may not be sent or the LDS order says hydro x# of tanks and it's business as usual for the operator.

My LDS has been giving me good fills since I started giving feedback on every tank pressure when they cooled so having the + is not an issue for me. I have bigger tanks if I need more air for a dive.

For a hydro outfit look for a big fire extinguisher company, if they don't hydro themselves they know who does 'cause all those extinguisher bottles need hydros.

Bob
-------------------------------
I may be old, but I’m not dead yet.

 

[halocline]

Once I asked for a plus rating on my 72s, and they came back with the words "no plus" stamped on the tank. That was because they didn't have the REE number. Just goes to show you there are some real idiots hydroing tanks.

 

[captain]

You can find all the hydro testers in the country here. You need one listed as high pressure. You will also notice that very few are listed as scuba shops.

PHMSA - Cylinders - Authorized DOT Cylinder Retesters: Domestic

 

[duckbill]

Make sure the hydrotester knows what the heck he is doing!
I used to have my tanks sent to the only guy around here that I knew of who would plus rate steel 72s. I later found out that his method was to test them at a test pressure in excess of 10 percent over the standard test pressure (i.e. data showed tested at 4166psi instead of 3750psi). Needless to say, I won't allow my tanks to be subjected to such abuse any more!

P.S. Yes, they all passed.

 

[idive2]

I have read that the test pressure for the plus is the same as the test
pressure for a standard hydro. And it is my understanding that it is a matter
of subracting the residual (after the test pressure has been released) cc's in
the burette from the test pressure cc's. Then subtracting the residual
cc's from the test pressure cc's and keeping that number under the REE number.
Can anyone who has done hydros confirm the pressure test is the same and when
an REE number is available it is just a matter of subtracting one value from
another ?

 

[captain]

I have read that the test pressure for the plus is the same as the test
pressure for a standard hydro. And it is my understanding that it is a matter
of subracting the residual (after the test pressure has been released) cc's in
the burette from the test pressure cc's. Then subtracting the residual
cc's from the test pressure cc's and keeping that number under the REE number.
Can anyone who has done hydros confirm the pressure test is the same and when
an REE number is available it is just a matter of subtracting one value from
another ?

Correct, if residual expansion is less than the REE it can be plus rated. Keep in mind it also must pass the 10% permanent expansion limit also.

 

[duckbill]

Can anyone who has done hydros confirm the pressure test is the same and when
an REE number is available it is just a matter of subtracting one value from
another ?

Don't expect to get a correct answer from someone who actually does hydros

Edit: Captain and I posted at the same time. My comment was not directed toward him. My understanding is the same as his, and, as far as I know, neither of us does hydros