You must know when the hydrostatic tests of your dive tank expire. DOT requirements require that tanks undergo a new test every 5 years. Check the markings on the shoulders of the tank for earliest hydro test date and latest visual inspection stamp. Luxfer recommends visual inspections every four months, especially for heavy users. If you see a tank that's older than 1990, request a newer model. If the tank was manufactured before 1990, look for the manufacturer's name and permit or exemption numbers. Aluminum cylinders are recommended. Dive operators who do not use aluminum cylinders are best avoided.
If you're a scuba diver, it's important to have your dive tanks hydrostatically tested on a regular basis. Hydrostatic testing is a procedure that checks the cylinder's elasticity and capacity. During this process, the cylinder is filled with fresh water and immersed in a water-filled jacket. This jacket is designed to withstand pressures much greater than a normal working pressure. The test cylinder is usually pressurized to five-thirds of its rated pressure. If there's a problem with elasticity, it could lead to catastrophic damage.
The DOT mandates a new hydrostatic testing every five years for dive tanks. Some dive tanks, however, require a test three years after the first hydrotest. The DOT also recommends that dive tanks undergo a visual inspection annually. Hydrostatic tests are especially important if you're using the same tank for many dives. The test will tell you if your cylinder is in good condition or needs to undergo a new hydrostatic test.
If you're a scuba diver, you should have your tank hydrostatically tested every five years to ensure it's in good condition. It will be marked with a permanent mark if it fails the test. Depending on how old your dive tank is, you may be able to salvage it if you've done all of the proper maintenance and retesting.
Luxfer cylinders made from a 6351 aluminum alloy are more likely to crack and explode. The alloy is subject to sustained load cracking, which occurs when a material is put under significant stress. This type of fracturing is not always visible and can take decades before it reaches a critical point. This type of tank has been the cause of many cylinder explosions and injuries, and Scuba Com has stopped accepting and filling cylinders with this alloy stamp.
The main reason for these problems is that diving equipment made of this alloy is more prone to corrosion than other types of metals. In addition to corrosion, a dive tank made of this material can have problems with regulators. The pressure in a tank decreases as the diver goes deeper, and the risk of fracturing or an explosion is lower. However, if a faulty valve or seal fails, the tank may still degrade or explode.
Fortunately, there are some precautions that you can take to minimize the risk of fracturing or explosions. It's important to keep your scuba tank away from sharp objects and always transport it in a car. Even the most protective tank can explode when punctured. A spark could ignite the gas inside, and cause an explosion. This is why a 6351 alloy cylinder should be stored out of reach of children.
Did you know that some Walter Kidde dive tanks have expired warranties? If so, you should definitely take a look at your tank. The company has issued a recall for aluminum tanks, as these tanks can crack when pressured. A few of these devastating explosions have led to numerous tank recalls. If you're looking for a new tank, you can check out the Walter Kidde website. You can also ask your dive shop about the expiry dates of your current tank.
Older tanks are known to be prone to bursting, and the valves on these models may fall off. The DOT safety guidelines for hydro should catch the older models if they're defective. In Florida, many stores won't fill older tanks. However, if you're considering a new dive tank, you should read the warranty terms carefully before buying. Remember that warranties are only good for a specific period of time, and they are only valid for the manufacturer.
While your tank may seem fine, it may have a defect or two. It may be corroded due to corrosion, or it may be cracked from the fill station. Both of these issues are often the fault of the fill station, which can pump water into your tank. A 6351 alloy has a defect called sustained load cracking. Luxfer Gas Cylinders used this alloy from 1971 through 1987. Walter Kidde also used this alloy to make scuba cylinders.