Regular SCUBA tank inspections are vital for diver safety. Neglecting to inspect a SCUBA tank can lead to catastrophic failure, which can cause injury or worse. In this guide, we cover the importance of tank inspections, the different types of inspections required, and what divers need to know to keep their cylinders safe.
Why SCUBA tank inspections are crucial
1. Preventing catastrophic failures
A SCUBA tank holds air at extremely high pressures, typically around 200-300 bar (2900-4350 psi). If the cylinder is weakened by corrosion, physical damage, or manufacturing flaws, it can rupture. Regular inspections ensure that the tank is structurally sound and capable of handling high pressure safely.
2. Identifying corrosion and damage
SCUBA tanks are regularly exposed to saltwater and general condensation, especially if stored empty for prolonged periods. This can lead to internal and external corrosion over time. Inspections help identify corrosion, cracks, or other damage that could compromise the tank's integrity.
3. Compliance with safety regulations
Most countries require SCUBA tanks to be inspected and tested at set intervals to ensure compliance with safety standards. This not only ensures diver safety but also helps dive centers and operators adhere to legal requirements.
Types of SCUBA tank inspection
1. Visual Inspection
- Frequency: Annually
- A visual inspection involves checking both the inside and outside of the tank for signs of corrosion, pitting, dents, or other damage. The inspector will also check the condition of the tank valve, O-ring, and threads.
- A certified technician will look inside the tank using a bright light and a mirror to identify any signs of internal corrosion or damage. The outside of the tank is also inspected for cracks, dents, or other damage that could weaken the structure.
- If the tank passes, it will receive a sticker indicating the next due inspection date.
2. Hydrostatic test
- Frequency: Every 2 years
- A hydrostatic test checks the tank’s ability to handle high pressures and identifies any structural weaknesses. During the test, the tank is pressurised to a level higher than its working pressure to ensure it can withstand the stress.
- If the tank passes, it is stamped with the date of the test, indicating when the next hydrostatic test is due.
Common issues found during tank inspections
1. Corrosion
- Internal corrosion: Moisture that enters the tank during improper filling or storage can lead to rust or corrosion inside the cylinder. This weakens the metal and compromises its ability to safely hold high-pressure gas.
- External corrosion: Tanks exposed to saltwater without proper rinsing can develop external corrosion, which can weaken the metal over time.
2. Cracks and pitting
- Cracks: Cracks, especially around the neck of the tank, can be caused by repeated pressurisation cycles. If a crack is found during inspection, the tank is deemed unsafe for use.
- Pitting: Pitting is the formation of small holes or depressions on the tank surface due to corrosion. Severe pitting can lead to structural weakness and failure.
3. Valve and thread damage
- Valve wear: The tank valve is subjected to regular use and can develop leaks or fail over time. Inspections involve checking valve functionality and replacing worn O-rings.
- Thread issues: The threads that connect the valve to the tank are critical. Damaged threads can lead to leaks or difficulty securing the valve properly.
Care for Your SCUBA Tank Between Inspections
1. Rinse thoroughly after every dive
Rinse your tank thoroughly with fresh water after each dive to remove salt and prevent external corrosion. Pay special attention to the valve area, as sand or salt deposits can accumulate there.
2. Store with a small amount of pressure
Store your SCUBA tank with about 30-50 bar (500-700 psi) of pressure. This helps keep moisture out of the cylinder, reducing the risk of internal corrosion. Never store a tank completely empty.
3. Avoid extreme temperatures
Do not store your tank in places with extreme temperatures. Excessive heat or cold can weaken the tank material and increase the risk of damage. Always store the tank in a cool, dry place.
4. Transport with care
When transporting your tank, make sure it is secure and cannot roll around or fall. Physical impacts can cause dents or other damage that could compromise the cylinder’s safety.
Working with certified inspectors
1. Certified technicians
Always have your tank inspected by a certified technician. These professionals have the necessary training and equipment to conduct thorough inspections and tests according to safety standards.
2. Understanding the inspection process
It’s a good idea to understand the basics of what’s involved in a visual or hydrostatic inspection. This allows you to ask the right questions and be confident that your tank is being properly assessed.
Common myths about SCUBA tank inspections
1. If it looks fine, it must be safe
Just because a tank looks fine from the outside doesn’t mean it’s safe. Internal corrosion and invisible cracks can make a tank dangerous to use. Regular inspections are the only way to ensure it’s truly safe.
2. Skipping inspections if the tank isn’t used often
Even if your tank hasn’t been used, it should still be inspected at regular intervals. Moisture can enter the tank even during storage, leading to internal rust and damage.
Conclusion
SCUBA tank inspections are a critical part of ensuring your safety as a diver. A well-maintained tank will provide reliable performance and reduce the risk of accidents due to structural failure. Make sure to follow the recommended inspection intervals and take care of your tank between dives to extend its life and keep yourself safe. Remember, there’s no substitute for a properly inspected and well-maintained SCUBA cylinder when it comes to your safety underwater.
