Scuba accident in a swimming pool close to my house

[CT-Rich]

I took a closer look at some of my valves, now that I have some daylight. Of the valves I checked so far.

• 4 valves have marking indicating threading
• 5 do not.

As far as tanks with markings? Don't know, because markings can be a pain to read, and I have a very random assortment of tanks.

This is one of the moments where you defer to the guy who has the correct tool for the job. The cost of having someone with correct tool check is far lower than the potential of being wrong.

I am sure who ever gets tagged with this mistake, will be wishing more care had been taken.

 

[Marie13]

Also out of curiosity:

Is there a good way to identify different threads, except the valve almost-but-not-quite screwing in all the way?

From what I hear, an my experience with some pony-tanks, you should just be able to easily hand-tighten most valves.

Do you have a mix of older and newer tanks or all new?

 

[runsongas]

this is an EU bureaucracy fail that they didn't pick a size that would have been different enough to prevent this from occurring when they made the m25 standard. they could have just used g3/4 also instead as the DIN fitting standard is g5/8 anyways.

 

[SlugLife]

Do you have a mix of older and newer tanks or all new?

Hah, quite a mix! I currently have

• 2x PST Steel 100s from 2004
• 4x AL 80 tanks, born 2000 to 2010, all "random"
• 2x AL 80 1987 tanks. These I'll be getting rid of very soon.
• 2x 19cu pony bottles. 1 is 1-year old, the other about 6 years old.
• 2x 6cu matching pony bottles (not sure year, but newish?)

I've been wanting to remove my ultra-nice valves from the 1987 tanks, so I can get rid of those tanks.

One dive-shop claimed to swap valves with tank-fills for no extra charge, but refused when I showed up, saying they only swapped valves with a $25 VIP. There's another LDS that claims to swap for free with a fill, so I'll try them next.

Worst case, I have serviced my own regulators, and what what I've seen swapping valves looks 100x easier (on the modern valves). If the threading is right, it's smoothly hand-tight the whole way with practically no resistance.

 

[BlueTrin]

this is an EU bureaucracy fail that they didn't pick a size that would have been different enough to prevent this from occurring when they made the m25 standard. they could have just used g3/4 also instead as the DIN fitting standard is g5/8 anyways.

It’s a bit weird to choose a fitting that could cause accidents I agree.

 

[ijdod]

@runsongas it gets better, there’s also the old French 25x2 SI standard (not the quite the same as M25x2), and of course the American DOT NPSM 3/4” which is not the same as G3/4”.

 

[runsongas]

G3/4 and 3/4 NPS have a different thread form so you can't really screw them up at least.

 

[Bob DBF]

G3/4 and 3/4 NPS have a different thread form so you can't really screw them up at least.

From my understanding from reading, they are the same.

Vacuum Fitting Conversions – Standard Sizes for Threads

The second is “G“, which is a straight pipe thread also known in the trade as BSPP, NPS or “G“, commonly used in Europe, Asia and most of the rest of the world. It is technically a Witworth thread which is actually a British Standard Pipe Parallel (BSPP) thread known as “G”. Per the ISO standard, the proper designation is “G” in front of the fraction.

 

[ofg-1]

O2 tank?

 

[runsongas]

@Bob DBF G3/4 is a 55 degree thread angle vs 60 degree for US NPT/NPS. the combination doesn't seal like it can for m25 and G3/4 as it ends up leaking so you don't create a ticking time bomb.

Thread angle - Wikipedia

en.wikipedia.org