For many divers, the markings around the neck(top) of the tank may well be like reading hieroglyphics. The only real numbers most divers need to know is the tank pressure that the tank will hold, the annual inspection date, and when the periodic tank inspection is due. I will talk about all these as well as the metal types of the of most popular tanks. All dive shop owners will be able to help you interrupt the markings as well as taking care of your tank. Please visit your local dive shop for more information. The marking are not hard to learn and I will attempt to take the mystery out of the markings.
You’ve probably already heard that there are two types of metals commonly used for scuba tanks: steel and aluminum. But what’s the difference between these two, and which one will best suit your style of diving? In this article, we discuss a few factors you need to consider when choosing between steel and aluminum tanks. Scuba cylinders (tanks) come in several capacities ranging from 6 to 130 cubic feet (cubic feet represent the gas capacity of the tank and 80 cubic tanks are the most popular size). Scuba tanks come in two basic metals: Aluminum and Steel Steel tanks cost more and are more durable and more negative buoyant in the water than aluminum tanks.
Material Cylinders are made out of two types of material: steel and aluminum (actually an aluminum alloy). Each have different properties that make it appealing for different types of construction and use. Steel cylinders are tough, making them resistant to damage.
Manufacturers of steel scuba cylinders included Pressed Steel Tank Co. (PST), Norris Industries, and Walter Kidde Co. The Italian firm Faber makes U.S. Department of Transportation (DOT) approved cylinders sold until recently under several brand names. Currently Faber cylinders are distributed by the Blue Steel Company. The size and working pressure of your Scuba tank can be determined by looking at the markings on the crown of your tank. There is a lot of information listed on the crown of the tank and the order in which the information is listed varies from tank to tank, but the codes are standardized and easy to read if you know what to look for.FIRST ROWGOVERNMENT APPROVAL
First set of letters either DOT or DOT/CTC. These stand for US Department of transportation and the Canadian Transportation Commission. If you travel to Canada and take tanks across the boarder, make sure it has this CTC marking on it. Most tanks sold in the US have the DOT stamp on it.METAL TYPE
Next set of letters tell what type metal the tank is made from. The 3A denotes carbon steel. Used for early tanks. This tank more prone to corrosion than chrome steel of aluminum.
The 3AA stands for chrome-molybdenum steel. It appears on virtually all steel tanks today.
Aluminum cylinders may bear the designations SP6498, E6498, or most times it is 3AL. First two designations identify permit numbers under which aluminum cylinders are manufactured. But the 3AL is the usual mark you will see on tanks manufactured in the US after July 1, 1982.WORKING PRESSURE
The next set of numbers, usually four, is the working pressure of the tank. This is expressed in pounds-per-square inch. The cylinder should not be filled past this point. The single exception to this is when you see a + sign at the end of the second row or next to this pressure. That plus sign is usually assigned to steel tank and means you can fill by 10% increase. Most aluminum tanks go to 3000 psi, a few go to 3300 psi. You need to look at this to see what your tank is rated at. Of course the dive shop you take you tanks to will look at this number.
What Two Metals Are Scuba Tanks Made From ItalySUBSEQUENT ROWSSERIAL NUMBERS
Some tanks have a second row while others may have more. All tanks have an unique number assigned to them to identify the tank, this is the serial number. May represent the size and lot number.
What Two Metals Are Scuba Tanks Made From RecycledMANUFACTURER IDENTIFICATION
This usually follows the serial number and describes the dealer who made the tank. PST is Pressed Steel Company, Luxfer, and Kidde are the common. HYDROSTATIC DATE
The cylinders initial date follows the manufacturer name. It consist of numbers representing month and year that the cylinder was tested. These numbers will be separated by the hydrostatic tester's initials or a special symbol that the tested had registered with the DOT. Each tank needs to be re-tested every 5 years. Each 5 year test date will appear somewhere at the top around the neck.
What Two Metals Are Scuba Tanks Made From Germany
What 2 Metals Are Scuba Tanks Made From
This is a brief explanation of tank markings. Like I mentioned above, ask you local dive shop to help you determine what your specific markings mean.
Please visit my sponsors links for some very cool things, which are free,