Torque value for cylinder valves

richieoflynn · March 12th, 2008, 10:31 PM

So as the title says... can someone please tell me the correct torque value for cylinder valves. Are they the same for alis and steel ?

The reason I ask is because I broke down a set of doubles this winter while I wasn't doing much diving to clean / regrease the valves and have a gander inside to see how they were looking. I made up a tool to remove the valves easily without damaging them and I also have a torque wrench that I use at work so rather than go upto LDS, I could finish them off at home. Mind you, my buddy in the dive shop is sound and makes a mean cup of tea but just to save me the bother of lugging them around.

Thanks,

Richie.

rjack · March 12th, 2008, 11:04 PM

Just very firmly hand tight is fine. The threads don't do any sealing - torqueing them just keeps the valve on when there's no/very little pressure inside. Even minimal 20bar will make it impossible for the valve to accidentally come off without a wrench. If you need to use a wrench on a valve to remove it that is a huge red flag. Be absolutely sure its working and the tank is empty. Best to put a small amount of gas in and let it out to be sure the valve can vent properly. Otherwise if you use a wrench you might be creating a deadly missile

richieoflynn · March 12th, 2008, 11:46 PM

Well that all sounds fairly logical when I think about it

However, I'm sure that there is definately a torque value somewhere either specified by a countrys safety standard or possibly from a valve or cylinder manufacturer. I know for example that the guys in the dive shop torque them but don't know where they got their info from and who told them 'hey, this is what you should be doing here'. Might ask him tomorrow for the craic and see what he says.

Richie.

GLOC · March 12th, 2008, 11:56 PM

Richie,

There is a standard but most people I know use the following standard...

"Hand tighten it, then twat it with the palm of the hand to tighten it a little bit more"

You are more likely to do damage to your hand than the valve or the cylinder this way

rjack · March 13th, 2008, 12:12 AM

That's my standard

I think one reason why dive shops like to use wrenches is so they are the only ones who can get the damned things off to do visuals. Ca-ching! Cynical, who me

richieoflynn · March 13th, 2008, 12:17 AM

Well folks, looks like the vote is unanimous... slap of the hand it is then

Leigh u · March 13th, 2008, 01:23 AM

Quote: (Originally Posted by GLOC)

Richie,

There is a standard but most people I know use the following standard...

"Hand tighten it, then twat it with the palm of the hand to tighten it a little bit more"

You are more likely to do damage to your hand than the valve or the cylinder this way

you said twat

we prefer smack

daviddem · March 13th, 2008, 02:25 AM

From the Luxfer Scuba Cylinder inspection guide, p21:

Quote:

We recommend that all straight thread valves be installed in Luxfer high-pressure aluminum scuba cylinders with a torque recommended by the valve manufacturer for aluminum cylinders.
Without a recommended torque from the valve manufacturer,we would recommend a torque of 50 lbf-ft, plus or minus 10 lbf-ft. All torquing should be done such that valve, valve components and cylinder are not damaged.

and also (same page):

Quote:

The application of a small quantity of lubricant to the valve threads is essential for the proper care of the valve and cylinder. We recommend that only Dow Corning Compound 111 be used on valve threads. Only a very small amount of the lube is needed, and only applied at the bottom of the valve threads. The lubricant will ride up the threads as it is installed. We only recommend this lubricant since it has proven compatible with cylinders and valves, doesn’t add any grease or oil to the cylinder, is safe to use, and helps prevent galvanic corrosion.

The complete guide can be downloaded here

I could not locate recommended torque for Sherwood, Thermo or MDE valves, and did not find any more info on the Faber or Eurocylinder websites.

david_1 · March 13th, 2008, 03:47 AM

Dow Corning Compound 111 SO WHAT IS IT ?

rjack · March 13th, 2008, 05:30 AM

Quote: (Originally Posted by david_1)

Dow Corning Compound 111 SO WHAT IS IT ?

A thick goopy non-O2 compatible silicon. Gotta use an O2 compatible lube if you partial pressure blend.

March 12th, 2008, 10:31 PM	#1 (permalink)
richieoflynn (Online) New Member Join Date: May 2007 Location: Ireland Posts: 52	Torque value for cylinder valves So as the title says... can someone please tell me the correct torque value for cylinder valves. Are they the same for alis and steel ? The reason I ask is because I broke down a set of doubles this winter while I wasn't doing much diving to clean / regrease the valves and have a gander inside to see how they were looking. I made up a tool to remove the valves easily without damaging them and I also have a torque wrench that I use at work so rather than go upto LDS, I could finish them off at home. Mind you, my buddy in the dive shop is sound and makes a mean cup of tea but just to save me the bother of lugging them around. Thanks, Richie.

March 12th, 2008, 11:56 PM	#4 (permalink)
GLOC (Online) Moderator Join Date: Nov 2005 Location: Fleet, Hants Posts: 1,950	Richie, There is a standard but most people I know use the following standard... "Hand tighten it, then twat it with the palm of the hand to tighten it a little bit more" You are more likely to do damage to your hand than the valve or the cylinder this way __________________ Gareth Images of Life Photography DIR Team Foxturd Travels Underwater and Further Afar If you don't have the time to do something right, where are you going to find the time to fix it? - Stephen King

March 13th, 2008, 01:23 AM	#7 (permalink)
Leigh u(Offline) We Go Down Join Date: Nov 2005 Location: Ottawa Canada Posts: 227	Quote: (Originally Posted by GLOC) Richie, There is a standard but most people I know use the following standard... "Hand tighten it, then twat it with the palm of the hand to tighten it a little bit more" You are more likely to do damage to your hand than the valve or the cylinder this way you said twat we prefer smack __________________ http://youtube.com/wegodown

March 12th, 2008, 11:04 PM	#2 (permalink)
rjack(Offline) wet behind the ears Join Date: Nov 2005 Location: Seattle, WA Posts: 860	Just very firmly hand tight is fine. The threads don't do any sealing - torqueing them just keeps the valve on when there's no/very little pressure inside. Even minimal 20bar will make it impossible for the valve to accidentally come off without a wrench. If you need to use a wrench on a valve to remove it that is a huge red flag. Be absolutely sure its working and the tank is empty. Best to put a small amount of gas in and let it out to be sure the valve can vent properly. Otherwise if you use a wrench you might be creating a deadly missile

March 12th, 2008, 11:46 PM	#3 (permalink)
richieoflynn (Online) New Member Join Date: May 2007 Location: Ireland Posts: 52	Well that all sounds fairly logical when I think about it However, I'm sure that there is definately a torque value somewhere either specified by a countrys safety standard or possibly from a valve or cylinder manufacturer. I know for example that the guys in the dive shop torque them but don't know where they got their info from and who told them 'hey, this is what you should be doing here'. Might ask him tomorrow for the craic and see what he says. Richie.

March 13th, 2008, 12:12 AM	#5 (permalink)
rjack(Offline) wet behind the ears Join Date: Nov 2005 Location: Seattle, WA Posts: 860	That's my standard I think one reason why dive shops like to use wrenches is so they are the only ones who can get the damned things off to do visuals. Ca-ching! Cynical, who me

March 13th, 2008, 12:17 AM	#6 (permalink)
richieoflynn (Online) New Member Join Date: May 2007 Location: Ireland Posts: 52	Well folks, looks like the vote is unanimous... slap of the hand it is then

March 13th, 2008, 02:25 AM	#8 (permalink)
daviddem(Offline) New Member Join Date: Feb 2007 Location: Dubai Posts: 111	From the Luxfer Scuba Cylinder inspection guide, p21: Quote: We recommend that all straight thread valves be installed in Luxfer high-pressure aluminum scuba cylinders with a torque recommended by the valve manufacturer for aluminum cylinders. Without a recommended torque from the valve manufacturer,we would recommend a torque of 50 lbf-ft, plus or minus 10 lbf-ft. All torquing should be done such that valve, valve components and cylinder are not damaged. and also (same page): Quote: The application of a small quantity of lubricant to the valve threads is essential for the proper care of the valve and cylinder. We recommend that only Dow Corning Compound 111 be used on valve threads. Only a very small amount of the lube is needed, and only applied at the bottom of the valve threads. The lubricant will ride up the threads as it is installed. We only recommend this lubricant since it has proven compatible with cylinders and valves, doesn’t add any grease or oil to the cylinder, is safe to use, and helps prevent galvanic corrosion. The complete guide can be downloaded here I could not locate recommended torque for Sherwood, Thermo or MDE valves, and did not find any more info on the Faber or Eurocylinder websites.

March 13th, 2008, 03:47 AM	#9 (permalink)
david_1(Offline) New Member Join Date: Jul 2006 Location: sussex Posts: 295	Dow Corning Compound 111 SO WHAT IS IT ?

March 13th, 2008, 05:30 AM	#10 (permalink)
rjack(Offline) wet behind the ears Join Date: Nov 2005 Location: Seattle, WA Posts: 860	Quote: (Originally Posted by david_1) Dow Corning Compound 111 SO WHAT IS IT ? A thick goopy non-O2 compatible silicon. Gotta use an O2 compatible lube if you partial pressure blend.