How often do most shops in your area require Nitrox tanks to be O2 cleaned?

[danktex]

You clean the tank every year but not the valve? It is my understanding that fires usually start in the valve. At least you are honest.

I come across HP banks every now and again. I will let you know next time. I have been meaning to come in and check out your shop. I have not been in there since Mark owned it.

 

[padiscubapro]

For the record, I am ready willing and able to bank 32 mix. All I need are the HP bank cylinders to store it in. Those boogers are pricey! If I could get my hands on 4 - 6 of them cheap, I would certainly invest the rest of the $$$ to make the setup happen.

For Nitrox fills, we do not require an overnight wait. We can usually fill your tanks on the spot. Granted, because of the partial pressure blending process, the fill takes longer than an air fill. However, its not like it takes hours or anything. I have several customers come in and get their tanks filled while they wait.

As far as O2 cleaning goes, we charge a slight premium to VIP a nitrox tank. That covers the cost to clean the tank. We do not require an annual rebuild on the valve. So far, our policy has not burned us, pardon the pun.

When it comes to contamination from regular compressed air fills, I think it depends on where you get your fills. When this thread started taking off, I check the latest test report on my fill station. Total gaseous hydrocarbons were 3.3 ppm, with a specification limit of 25 ppm. I doubt all 3.3 would adhere to the tank on each fill, so I'm not sure how many fills it would take to reach a critical level. Too much math for my little brain.

Mack,
If I had a choice of cleaning a valve or cleaning a tank,, The valve would win every time.. A cylinder is a HUGE heat sink.. An oxygen fire is much less likely to start at the cylinder than the valve.. Having the valve clean is MUCH MUCH more important..

as to gaseous hydrocarbons, these are not an issue, its the condensing hydrocarbons that are a problem.. The majority of measured gaseous hydrocarbons are methane, which is naturaaly found in atmospheric air at low levels.. Parden the pun, but pass gas near your air inlet and you'll probably spike more than 25ppm..

 

[Mack Diver]

I guess I was not clear in what I said. By cleaning the tank, I should have said tank and valve. However, we do not rebuild the valve, unless their is an issue with the valves operation.

We do have some customers that want their valve rebuilt on an annual basis and we oblige them. I think it comes down to how much the tank is used during the year. Folks that do a lot of dives and therefore get lots of fills should have a more thorough service done. Folks that use their tanks just a few times a year can probably get by with a less stringent service.

However, as has been mentioned, the risk of fire is at the time of partial pressure filling. Therefore, it is up to each shop owner to set their own policy. If you do not agree with that policy, take your tanks to another shop.

 

[oxyhacker]

Just out of curiousity, how are you cleaning the valve when you don't rebuild it?

I'm curious because we are in an area of ambiguous nomenclature here. Some people would consider dismantling a valve, inspecting and cleaning the parts, and replacing anything that needs it to be "rebuilding". Others would consider that to be "cleaning and lubing" or "servicing" and say that to be considered a rebuild, a full OH kit should be installed, so that all the wearing parts including the seat are replaced.

Regardless of which interpretation one prefers, you can't clean a valve without taking it completely apart, and I agree with PSP that the valve is a much greater concern when O2 cleaning than the tank.

I guess I was not clear in what I said. By cleaning the tank, I should have said tank and valve. However, we do not rebuild the valve, unless their is an issue with the valves operation.