Gear : HYDRO VS. VIP

What is the difference between a hydro and visual inspection and why are they required?

To ensure the safety of all who may come in contact with SCUBA cylinders; we fill, handle and use only those cylinders which have a current hydrostatic test mark (5 years) and have a valid, recognized visual inspection sticker (one year or less). We can arrange these services if your cylinder does not comply. When a cylinder fails our comprehensive evaluation, you may be certain that a significant potential danger has been identified. We will show you both the problem and the documents that guided our decision.

Hydrostatic Testing: SCUBA tanks must be hydro tested every five years. In this test the tank is filled with water and then lowered into a water filled chamber. The tank is then pressurized to 5/3 of its operating pressure. The test is done with water instead of air because should there be a failure the water does not hold potential energy and the failure would be less explosive.

Once pressurized the tank is measured for expansion. If the expansion is not within tolerances the tank fails the test and must be discarded.

The test is the same for aluminum and steel tanks. The burst disc is replace on the valve at this time.

VIP – Visual Inspection: Cylinders should be periodically inspected according to their conditions of use by an experienced, competent visual inspector. Have your cylinder inspected once every four months if you fill it five or more times per week or if you use your cylinder wherever damage is more likely than in normal diving use, and/or your cylinder shows signs of damage or corrosion. Have your cylinder inspected once every twelve months when it is filled four times a week or less and used under normal conditions and is being properly cared for.

Eddy Current Test: Aluminum tanks manufactured before 1990 and made of 6351-T6 alloy have been found to be subject to neck cracks. These tanks need to have an eddy current test which involves screwing a threaded prob into the neck of the tank to test for cracks that may be too small to be seen by the naked eye. This does not replace the need for a visual inspection!

NEVER:
• completely discharge a cylinder as it can lead to water seeping into the cylinder, except when you’re planning to remove the valve;
• overfill aluminum cylinders;
• artificially heat your cylinder;
• fill or partially fill a cylinder with pure oxygen;
• fill a cylinder if it leaks;
• use a cylinder past its retest date;
• use a cylinder that hasn’t been visually inspected according to its condition of use;
• over-torque the valve;
• remove, obscure or alter labels or markings;
• use excess Dow 111 lubricant on valve; or
• fast fill (over 1000 psig/minute) your scuba cylinder.

If you have any questions regarding why cylinder inspection and testing is required, we’re happy to go over more details. We reserve the right to refuse an air fill for a cylinder we do not feel is safe and current with its testing! Certification cards are required for all air fills.