Gear – Page 2 – Diving Info

If you plan on diving more often, you'll want to have your own scuba tank in the future. It takes away the hassle of renting a cylinder every time you go for a dive. How long do scuba tanks last? That's a question that usually comes up when looking to purchase one. Scuba tanks can last up to 15–20 years, depending on several factors. Those include frequency of use, material composition, diving environment, and maintenance. Let’s look at how each factor affects the lifespan of a scuba tank in the following sections. How Long Do Scuba Tanks Last? Most scuba tanks are aluminum or steel. Between these two, steel cylinders are likely to last longer, with a life expectancy of 15–20 years. Aluminum tanks are also durable and can reach 10–15 years. Yet, never rely on these values or always expect your tank to be in good condition. Perform routine checking and inspection before going for a dive. Failure of your diving equipment in the water can be lethal, so be cautious. What Factors Affect How Long Scuba Tanks Last? Several factors can shorten or lengthen your tank's lifespan. Here’s a list for your guidance: 1. Construction Material The type of material used in your scuba tank is a factor in its life expectancy. In particular, aluminum tanks are softer. That makes them more vulnerable to dents, cracks, and scratches. These can compromise your tank’s integrity. On the other hand, steel tanks are more susceptible to corrosion. The extent of damage due to this occurrence will determine the tank’s usability and affect its lifespan. 2. Frequency of Use Naturally, how often a scuba tank is used affects its lifespan. The more you dive, the more the cylinder is subjected to handling issues, which can shorten its lifespan. It may bump into objects while you carry it around or during transport and may incur unwanted damage. Frequent use also means more air fills. During this process, tanks are exposed to possible moisture attacks. This can lead to oxidation and corrosion that can diminish a tank’s performance. In the case of steel tanks, rust is the product of corrosion. This is a big problem, especially in interiors. Removal will require special equipment and periodic tumbling. However, rust may still exist no matter how careful you are. After all, moisture isn’t completely avoidable. Even the air you breathe contains humidity, so expect rusting at some point. Aluminum tanks are equally susceptible to corrosion, although in a different form. The oxidation reaction is known as pitting corrosion. Instead of rust, a layer of aluminum oxide is produced. This powdery substance isn’t destructive to the aluminum material. In fact, it even prevents further corrosion. Nevertheless, excessive amounts can be troublesome. That’s especially true when present at the valve and thread interface. When this happens, the regulator interiors can get damaged. This can create serious problems if left unchecked and then used underwater. As you may know, the regulator plays an essential role in your gear since it allows you to inhale air at an acceptable pressure. Imagine not having a regulator. You’ll then be looking at a standard 3000 psi of compressed air or nitrox. Your lungs will blow up at that pressure. Therefore, remove aluminum oxide and rust at all costs. 3. Environment or Exposure to Seawater Your scuba tank will be submerged in water. That alone makes it prone to corrosion and shortens its lifespan. What's worse is when you regularly dive in seawater. The combination of moisture, salt, and oxygen speeds up the corrosion of your tanks. To put it in perspective, the salt in seawater corrodes metal five times faster than when it's in freshwater. Plus, the high humidity in ocean air corrodes at a rate that’s 10 times higher than air with normal humidity. Although tanks are made up of alloys, they’re still mainly metal. So expect your tank to degrade faster when diving frequently in saltwater. 4. Maintenance Proper care and maintenance of your scuba tank can lengthen its lifespan. Observe the following best practices for this purpose: Rinse After Use Rinse your scuba tanks with fresh water after a dive session. This ensures the removal of contaminants and unnecessary salt buildup, especially after a seawater dive. Just make sure to dry it with warm air afterward, so it doesn’t corrode. Don’t Overfill Scuba tanks have specific capacities and pressure ratings. Use these values as your guide when doing air fills. If at a dive shop, remind personnel about the limits too. Moreover, avoid overfilling at all times as this adds pressure on the tank. When this happens, the regulator can rupture and can lead to an explosion. In case you overfill, drain the air slowly. A rapid release can cause moisture to develop in the interiors and may corrode the tank. To go about that, submerge a portion of the tank in shallow water for safety. Make sure the valve is above the water, then let the air out slowly. Don’t Leave Tank Empty or Full The amount of air left in the tank is another factor in its lifespan. Pay extra attention to this, especially when looking at long-term storage. It isn’t advisable to empty the air in the tank, though. But it shouldn’t be full as well. That’s because an empty tank is prone to moisture attack. At best, you should make room for air, with at least 100–300 psi to prevent this from happening. Similarly, a full tank poses several issues. One, the cylinder will need to bear the pressure inside. Under prolonged storage, this weakens the tank. Second, more air inside the tank increases internal rusting. Lastly, but more importantly, external corrosion may occur and degrade the equipment. Anyone nearby may be in danger once the tank gives out. Store in an Upright Position Ideally, diving cylinders should be stored upright in a tank holder. The reason behind this is that tanks are designed with thicker bottom portions. In an upright position, corrosion will happen at the bottom. So, when you clean out corroded material, it won't degrade the tank as much as when the corrosion is on the sides. Moreover, corrosion is easier to spot when it’s at the bottom. Store in Cool and Dry Conditions Never store your tank in a hot area, especially when it's full. This is because of two things. First, gasses expand at high temperatures. If the tank cannot contain these, chances are, they’ll escape and find a release. An explosion is a possibility if too much pressure builds up. Second, the tank also expands with high heat. Once the temperature cools down, it’ll contract. These changes wear out the tank and shorten its lifespan. Thus, store the tank in an area with cool and stable temperatures and avoid direct sunlight. Additionally, ensure dry conditions to avoid corrosion. Fill Your Tank at Credible Dive Shops Make sure to fill your scuba tank at trusted dive shops. This will assure you that you’re getting high-quality air. Remember, you’ll be inhaling this throughout your dive. Even the slightest contamination can damage your tank. Worse, if toxic gasses are in the mix, you may suffer from serious health concerns. These can be deadly as well. Do Regular Inspection A yearly visual inspection is a requirement you should meet for your scuba tank. Doing your regular inspections can be beneficial to assess the tank’s integrity too. Check for any signs of corrosion or damage. If you find any, send your tank over to a reputable dive shop or repair establishment. Comply with Visual Inspections As mentioned, you should comply with a yearly visual inspection conducted by a licensed technician. These professionals check external and internal tank parts for dents, cracks, and corrosion. They inspect all attachments, too. A sticker is issued if your tank passes. This will indicate the date of inspection and expiration. Take note, credible dive shops usually look for this before air-filling your tank. If you’re renting a cylinder, the inspection sticker is also something you should pay attention to. This somehow guarantees that the tank is in good working condition. Do Hydrostatic Tests On top of routine visual inspection, hydrostatic testing is performed every five years. Do check local regulations for any changes as well. This test checks the ability of your tank to handle more refills. Specialized equipment is used for this and the tank is submerged in water for safety. First, the tank is filled with water—around 5/3 of the maximum capacity. Afterward, it’s pressurized up to 167% of its specified pressure. The aluminum or steel will react by flexing, which is measured by the water’s displacement. The cylinder should go back to its original shape to pass. Wrapping Up How long do scuba tanks last? A quick answer is that aluminum and steel tanks can last up to 15–20 years. However, several factors can affect this. For starters, the inherent characteristics of aluminum and steel, like susceptibility to dents and corrosion can shorten a tank’s lifespan. The same is true with frequent use and regular seawater diving. Nevertheless, extend your tank's lifespan with proper care, handling, and maintenance.