Cylinder Testing Standards - Where?

[Graham Smith]

The club has just had a load of cylinders tested with mixed results. Some require internal blasting, some have passed with flying colours. However, some have apparently failed on fairly subjective criteria such as needing repainting or valve threads worn.

What I am after is a copy of the test standards, i.e. what is the standard that the test centre is measuring against? I would like to be able to see to what degree the external paint can be damaged before failing the test. How badly worn does a valve thread need to be before it is considered dangerous? This is so a decision can be made as to whether it is even worth sending the tank for testing or if it is worth asking for a second opinion if it fails, something along the lines of the M.O.T. Guidelines so you can at least have a rough idea of the minimum standards.

Do these exist in the public domain? Anyone got any links?

Cheers,

[Prometheus]

Don't know about the paint question , but the thread test is with a go/no go thread guage so it either passes or doesn't , as I found to my cost with a 7lt alloy.

[Morag]

As far as the thread test is also concerned, the tolerance (or soemthing) is lower during manufacture than during test. Therefore, it would be perfectly possible for a valve made to manufacture standards to go straight to a testing centre, and fail.

(AFIUI)

[Gav]

These may be able to help. Repsonded promptly to an email I sent querying the 15 month test period of O2 cleaning.

Scuba Industries Trade Association

[fatone]

Most large libary's hold the standards and you can photocopy up to 10%, of the standard.
The standard's are BS-EN 1968:2002 steel & BS-EN 1802:2002 aluminium.

The go / no go thread gauge's should have had a certificate of callibration done within 12 months. Tidy shops will let you see the fault, i.e. the dicky thread with their gauge, even better shop's have two gauges to reduce the likelyhood of the one they use all the time, (and has a callibration cert.) being out of compliance, i.e. the bloke dropped it on the floor last week !
Paint, or not, on a cylinder is not part of the standard, however the corrosion that might have removed the paint is.

[bubbleless]

These may be able to help. Repsonded promptly to an email I sent querying the 15 month test period of O2 cleaning.

Scuba Industries Trade Association

What did they say??

Worn threads as said previously are tested by go/nogo also some valves were a problem failing on there first test , so should be returned to supplier.

The paint issue is also the corrosion problem its a percentage of the cylinder surface

[Scubafill]

The club has just had a load of cylinders tested with mixed results. Some require internal blasting, some have passed with flying colours. However, some have apparently failed on fairly subjective criteria such as needing repainting or valve threads worn.

What I am after is a copy of the test standards, i.e. what is the standard that the test centre is measuring against? I would like to be able to see to what degree the external paint can be damaged before failing the test. How badly worn does a valve thread need to be before it is considered dangerous? This is so a decision can be made as to whether it is even worth sending the tank for testing or if it is worth asking for a second opinion if it fails, something along the lines of the M.O.T. Guidelines so you can at least have a rough idea of the minimum standards.

Do these exist in the public domain? Anyone got any links?

Cheers,

This is the reply I got from the testing agency when I queried why they had failed the cylinders on external paintwork. The company wanted £40 to paint each cylinder. With painting, testing and O2 clean £160 + VAT - probably cheaper to buy a new twinset.

I have had cylinders tested in the past where the tester scraped off the paint to check for rust errosion under bubbles, been happy and covered the area with primer.

DIR kit does not include cylinder boots, are these cylinders going to fail because the base has damaged paintwork or light rusting?

Seems like the elf an safety brigade have joined the jobsworths to rip the divers yet again

[fatone]

You might be missing the point here.
They have not failed the paintwork, they have questioned the blistering, and failed the cylinder, and assumed that it is corrossion under the paintwork causing the blistering !

I would suggest you sand them down, prime, and repaint them, and then take them back to another test station who should not queery the good paint, and i am sure you would have not filled in any oxidisation pits !

There are laid down examples in the standards that say what %, of what type of corrossion, is allowed on a cylinder. It is not subjective. It is usualy 10 or 20% depending on the type of corrossion, bearing in mind that your (modern) cylinders will show a minimum wall thickness of say 4 - 5mm, 10% of that is .4mm ! That's a pretty small pit.

[Scubafill]

You might be missing the point here.
They have not failed the paintwork, they have questioned the blistering, and failed the cylinder, and assumed that it is corrossion under the paintwork causing the blistering !

I would suggest you sand them down, prime, and repaint them, and then take them back to another test station who should not queery the good paint, and i am sure you would have not filled in any oxidisation pits !

There are laid down examples in the standards that say what %, of what type of corrossion, is allowed on a cylinder. It is not subjective. It is usualy 10 or 20% depending on the type of corrossion, bearing in mind that your (modern) cylinders will show a minimum wall thickness of say 4 - 5mm, 10% of that is .4mm ! That's a pretty small pit.

Thanks for the info.
I have a number of cylinders and think I would recognise any serious blistering and dealt with the problem by repainting or disposing of the cylinders.
I will of course strip down the cylinders, treat them accordinglyand have them tested elseware as you have suggested. Funnily enough a member of my club had identified a different test station with a better deal.
I still feel a little miffed that there is and inspection charge of £16 each or a repaint charge of £40 each. Dammed if you do - dammed if you don't.

It's a bit like getting parts for a regulator - closed shop under elf and safety - But thats a different story