The Importance of Scuba Cylinder Maintenance and Inspections
Scuba divers depend on their equipment to survive underwater. It’s why manufacturers and common sense require divers to proactively service their equipment.
When it comes to scuba cylinders, regulators mandate specific inspections and testing to ensure the integrity of the tank.
According to the Divers Alert Network (DAN), Every year, there are preventable accidents involving scuba, rebreather, and oxygen cylinders.
Jupiter Dive Center’s service technicians are specially trained and certified to make sure your tanks get the attention they need to keep you safe.
It’s All About Safety
That cylinder on your back? Calling it a bomb is a bit over the top, but there is a reason that the construction of high-pressure containers is classified as hazardous materials by the U.S. Occupational Safety and Health Administration (OSHA). Then there’s the fact that it’s actually the Department of Transportation that sets the engineering and manufacturing standards for scuba tanks.
One of the reasons divers don’t give much thought to servicing their tanks is that tanks can appear to be indestructible. Sadly, they are not. The good news is that it doesn’t take much effort to ensure your tank is in compliance with safety standards.
Required Inspections
The two most common cylinder inspections are hydrostatic testing and visual inspections. You’ll often hear them referred to as a hydro and VIP.
Visual Inspections
Should be performed annually or more often if moisture or damage is suspected.
During the test, a technician will first inspect the outside of the tank, looking for dents or damage to both the cylinder and valve.
Then they’ll insert a light into the tank and look for dents, pitting, and signs of corrosion or moisture.
Hydrostatic Testing
Checks the cylinder’s flexibility and the metal’s integrity while under pressure. In the U.S., federal law mandates hydrostatic testing every five years and requires scuba shops as a commercial entity to adhere to the timeline. The takeaway? If your tank needs to undergo hydrostatic testing, don’t expect to get an air fill first. (If you’re having trouble sleeping, U.S. Code of Federal Regulations (CFR), specifically 49 CFR 180.209 Table 1, has a lot more details that go well beyond Scuba cylinders.)
Air Fills
Every time a tank is filled, the fill station technician is going to check out several things, starting with the markings on your tank. Stamped into the metal of every tank are some or all of the following: the identification of the alloy of the tank; its serial number; the working pressure; manufacturer’s identification; the date the tank was made; the test pressure used for hydrostatic testing; and the date(s) when hydrostatic test(s) were completed.
In addition to the engraved marks, stickers are added to the tank after the cylinder passes its VIP and include the date the inspection was performed. Don’t remove this decal! If a tank doesn’t have this documentation, you’ll need a new test.
Are you a Nitrox diver? Air and enriched air cylinders are not interchangeable, and Nitrox tanks will have a different sticker designating them as an Oxygen Clean tank. Be prepared to show your Enriched Air Certification card to get this cylinder filled.
Easy Ways to Care for Your Cylinder
In addition to the required inspections mentioned above, there are several steps you can take to extend the life of your tank.
1. Prevent moisture from entering your tank by keeping at least 300 psi in the tank. Moisture inside a tank leads to corrosion. If you do run your tank dry, you should have it visually inspected before putting it back in service.
2. After your last dive of the day, and after you’ve removed your regulator, gently open the tank valve to blow out any remaining moisture.
3. Store the tank standing up, but make sure it’s secure so it doesn’t get knocked over, which can damage it. Tank boots or blocks are good options.
4. Protect your cylinder from excessive heat. Car trunks and garages can get hot (especially near heat sources like the water heater), and as the temperature rises, the pressure inside the tank will increase. If the pressure gets too high, the burst disk on the tank valve could blow. Not only does the rupture sound pretty dramatic, but a small piece of metal will be expelled, and if the tank is unsecured, the escaping air will cause the tank to whip around, possibly causing injury or property damage. To add insult to injury, the rapid air drain can cause condensation inside the tank, exactly the kind of thing you’re trying to avoid in #1 above.
5. Open and close your valve gently. Remember when you open it up and come to the end, ease it back a bit. Cranking it open or closed could damage the valve.
Buyer Beware
If a tank has been condemned, both the code specification and pressure testing should be covered with Xs. But there are also tanks out there that dive shops won’t fill, chief among them tanks made from 6351 alloy that were made before 1990.
Ideally, if you are buying a used tank, the seller would have the tank’s service records. The reality is, they probably won’t. The tank markings and an internet search will go a long way in determining if you bought a usable tank or a doorstop that no reputable dive shop will fill.
At Jupiter Dive Center, your safety is our priority. Scuba diving, like many sports, has its risks, but maintaining and servicing your equipment reduces those risks considerably. And winter is the perfect time to bring in your tanks and other equipment that are due for service into the shop!
We’ll have you back on the boat in no time! (And we have tanks you can rent if you want to dive right away!) Call us at 561-745-7807 for more information about a service or book your dive online today!
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