Skating101
Long term storage of filled steel cylinders will not pose a problem. Steel cylinders are not subject to sustained load cracking like aluminum, especially the older 6351 aluminum cylinders.
The whole PO2 discussion has some theoretical merit but the data set is pitiful and in the scope of in-season diving has no merit. I wouldn't even consider this risk unless you're taking 6 or more months away from he sport. Over true long term storage it falls in to the "can't hurt" category. Dry filled cylinders had been dormant for decades at a time and were pristine when opened the element of moisture is the real risk.
Another discussion centers around fire. In the event of a fire it is said that gas expansion in a full cylinder will cause the burst disc to safely release the contents before the cylinder has a catastrophic failure. When stored in the 300-500 PSI range the energy contained is limited and failure won't be dramatic. Somewhere between full and nearly empty there is the potential for a cylinder with dangerous energy to fail and become destructive / dangerous. The bottom line is to try storing either near empty or full. It's all shades of gray as many of us will have such partial fill handy for cleaning out computers, testing regulators and other utility uses.
Don't hesitate to keep all cylinders charged and ready during the season.
Doc Harry's suggestion of periodic inspections is above and beyond what most divers do but it does have merit. To do this you need a unique relationship with a shop or a trans-fill whip or if you're styling, a compressor. If you show up with an empty cylinder you have a real chance of getting hit with a mid-year VIP fee. After a recent round of hydro tests I had one cylinder needing cleaning for a spoon full of water in the base. Since I know the pressure never dropped to allow water to enter it either entered while filling or the drying after hydro was not thorough. Since I own a trans-fill whip I'll consider doing an adhoc visual not long after future hydros.
Keep them filled and and dive regularly and it will all be good.
Pete
Long term storage of filled steel cylinders will not pose a problem. Steel cylinders are not subject to sustained load cracking like aluminum, especially the older 6351 aluminum cylinders.
The whole PO2 discussion has some theoretical merit but the data set is pitiful and in the scope of in-season diving has no merit. I wouldn't even consider this risk unless you're taking 6 or more months away from he sport. Over true long term storage it falls in to the "can't hurt" category. Dry filled cylinders had been dormant for decades at a time and were pristine when opened the element of moisture is the real risk.
Another discussion centers around fire. In the event of a fire it is said that gas expansion in a full cylinder will cause the burst disc to safely release the contents before the cylinder has a catastrophic failure. When stored in the 300-500 PSI range the energy contained is limited and failure won't be dramatic. Somewhere between full and nearly empty there is the potential for a cylinder with dangerous energy to fail and become destructive / dangerous. The bottom line is to try storing either near empty or full. It's all shades of gray as many of us will have such partial fill handy for cleaning out computers, testing regulators and other utility uses.
Don't hesitate to keep all cylinders charged and ready during the season.
Doc Harry's suggestion of periodic inspections is above and beyond what most divers do but it does have merit. To do this you need a unique relationship with a shop or a trans-fill whip or if you're styling, a compressor. If you show up with an empty cylinder you have a real chance of getting hit with a mid-year VIP fee. After a recent round of hydro tests I had one cylinder needing cleaning for a spoon full of water in the base. Since I know the pressure never dropped to allow water to enter it either entered while filling or the drying after hydro was not thorough. Since I own a trans-fill whip I'll consider doing an adhoc visual not long after future hydros.
Keep them filled and and dive regularly and it will all be good.
Pete
