DOT Hydro Testing Services

Flatirons Scuba is a Department of Transportation certified Hydrostatic Re-Testing Facility (RIN # I551). We can safely test and certify most SCUBA, Avalanche Pack, SCBA, Aviation, Airsoft/Paintball,CO2 and Oxygen tanks with quick turnaround time. See below for our prices and frequently asked questions

Tanks that Have DOT cylinder specifications that we can Hydrotest:
           3A, 3AA, 3AL, 3HT, and special permits 8162,7235,7277,8059,10019,9634,9716,10915,11194,13583,              9894,10147,10664,10905,10970,11005,9421,9791,9909 and 10869

Frequently Asked Questions:

What Is Hydrostatic Testing?

Hydro testing consists of three main steps:

• Perform a visual inspection of the tank
• Place the tank inside a steel water jacket and pressurize to a specified PSI
• Measure the tank wall expansion

Testing a tank in this way checks for permanent expansion or overexpansion of the tank walls, indicating unsafe structural deficiencies. All testing is done within a water jacket to ensure safety in case of a catastrophic tank failure.

Why is hydrostatic testing necessary?

Because it’s the law! Pressure tanks (including all SCUBA tanks!) are regulated by the Department of Transportation. Every tank must pass an initial DOT certification, visual inspection, and hydrostatic test prior to being sold, and before being filled.

How often do my tanks need to be tested?

The DOT mandates a new hydrostatic test every 5 years after the initial test, some special tanks are 3 years hydro tests.  Visual inspections are required yearly on scuba cylinders. 

What are the common reasons for tank failure?

Weak valve threads is a common issue. Corrosion inside the tank can also cause a hydro failure

If my tank fails, can I still use it?

DOT regulations states that a tank that fails during hydrostatic testing cannot be filled again, and will not be given a test stamp. No reputable dive shop will fill a tank without a hydro test stamp.  The tank serial # is stamped out with an X, and the cylinder threads are scored so that it cannot be filled again. 

What is sustained load Cracking and which cylinders are affected?  
There were certain manufacturers that used a special alloy 6351-T6 in the manufacturer of Aluminum cylinders.   This alloy was prone over time to have load cracking.  What that means is the pressure of the tank could eventually cause cracks in the neck of the cylinder.   Most of these tanks are 45 plus years old.  Because of the known problems and age we will not test or fill this type of cylinder.   

Here are the effected years for CYLINDERS MAUFACTURED WITH 6351-T6 ALLOY that  WE WILL NOT HYDRO:

WALTER KIDDIE CYLINDERS MANUFACTURED Jan 72 - Dec 31, 1989
CYLINDERS MARKED AS SP7042 OR E7042 prior to July 1982
LUXFER CYLINDERS MANUFACTURED Nov 71 - May 31, 1988
CYLINDERS MARKED AS SP6498 OR E6498 MANUFACTURED prior to July 1982 (THAT MAY BE ADDITIONALLY MARKED WITH 3AL  ABOVE IT)
Any Chinese cylinders imported that DO NOT INDICATE DOT OR SP

WE WILL HYDRO:

CATALINA 1986 - CURRENT 
LUXFER June 1, 1988 - CURRENT

ALL OTHER CYLINDERS that Have DOT cylinder specifications AND ARE NOT ON OUR 'WILL NOT HYDRO LIST'  WHICH INCLUDES:
           DOT 3A, 3AA, 3AL, 3HT, and SPECIAL PERMITS 8162,7235,7277,8059,10019,9634,9716,10915,11194,13583,              9894,10147,10664,10905,10970,11005,9421,9791,9909 and 10869