most of our guys are turning towards powerful pcp and its a must to know how to read the marking on the scuba tank for our own safety of shooting faternity .know about your own new / refurb tanks
http://www.ehow.com/how_5671711_read-scuba-tank.html
Place the scuba tank on the table and orient it so that the tank valve is pointing to you. Place ankle weights on each side of the scuba tank to secure its position.
Step 2Identify three rows of imprinted letters at the top (crown) of the tank, near the tank valve. Write down each row of letters and numbers.
Step 3Translate the first row of information using the legend below and reading each line from left to right:
Transport mark: "TC" or "CTC" means "Transport Canada"
Tank material: "3AL" means the tank is aluminum
Working pressure in bar (e.g., M207)
Tare weight in kilograms (e.g., T11.3KG)
Step 4Translate the markings in the middle row:
"DOT" specifies US Department of Transportation
Tank material code (e.g., "3AL" is the code in the US)
Working pressure in PSI (e.g., 3000)
Tank model (e.g., S80)
Manufacturer name or code (e.g., LUXFER or M4002)
Tank serial number assigned (e.g., U123456)
Step 5Translate the markings on the bottom line:
Month and year of hydrostatic test, each expressed in two digits and separated by an inspection code (e.g., 01A00 for January 2000 independently inspected)
Carbon dioxide capacity (e.g., 20#CO2)
Tare weight in pounds (TW24.9)
Step 6Check whether additional markings are included such as:
Overfill is indicated with a "+" sign which enables some steel tanks to be filled 10% greater than the pressure indicated on the tank (see Step 3 or Step 4)
Test pressure in PSI (e.g., TP4500 which is greater than the working pressure)
Technical Support Document
Crown Markings of a Standard SCUBA Cylinder
http://www.catalinacylinders.com/markscuba.html
Example of the crown marking on an S80 SCUBA Cylinder:
DOT-3AL3000..ASXXXXXXX M4002 07C08 CATALINA S80 SP12 TC-3ALM207
Marking Description
DOT-3AL The U.S. regulatory authority, the Department of Transportation (DOT), and specification, 3AL, to which the cylinder is manufactured in compliance (required mark).
3000 The service pressure, in pounds per square inch (psi), of the cylinder (required mark).
ASXXXXXXX The serial number of the cylinder. For Catalina Cylinders, the serial number prefix of "AS" is specific to the S80 (80 cu ft, 3000 psi) SCUBA cylinders followed by a six digit number.
M4002 The M-number or Manufacturers Number issued by the DOT to the manufacturer, Catalina Cylinders (required mark). This mark is recognized by TC
07C08 The original hydrostatic test date of the cylinder, month followed by year, performed at the time of manufacture of the cylinder. The "*" represents the symbol of the Independent Inspection Agency (IIA) performing the inspection of and certifying the acceptance of the cylinder at the time of manufacture (required mark).
CATALINA The name of the manufacturer of the cylinder.
S80 The cylinder identifier. It identifies the market, "S" for SCUBA, and capacity, "80" for a capacity of 80cuft charge, of the cylinder.
SP12 The cylinder outlet thread designation as specified in CGA TB-16.
TC-3ALM The Canadian regulatory authority, Transport Canada (TC), and specification, 3ALM, to which the cylinder is manufactured in compliance (required mark).
207 The service pressure of the cylinder expressed in metric units, bars (required mark).
Scuba Tank Markings
How to read the markings on a Scuba Tank
http://www.scubagonewild.com/documents/ ... kings.html
Explanation of the marks in the top line.
These are used in Canada but you might also find them on some U.S. tanks as well as the U.S. markings
"TC" or CTC (an older mark) Transport Canada
"3AL" Aluminum specification (Canada)
"M124" Service pressure (bar)
"T11.3KG" Tare weight (Kilograms)
Explanation of the marks in the middle line. (United States)
"DOT" United States Department of Transportation
"3AL" Aluminum specification (USA)
"1800" Service pressure (PSI)
"U372530" Serial number
"LUXFER" or M#### Manufacturing plant or distributor identification
Other manufacturers names you might see here are Catalina, Faber or P or PST ( for Pressed Steel)
You might also see the name of a scuba company such as Scubapro or USD.
If they order a large quantity of tanks they may choose to have their name used instead of the manufacturer.
Explanation of the marks in the bottom line.
"01" Month of manufacture
"A" Mark of independent inspector
"98" Year of manufacture
If it is a steel tank and there is a + stamped after the year it means that the tank may be filled to a pressure 10% higher than the pressure shown on the tank.
Aluminum tanks never have this designation.
Every 5 years, all tanks have to be hydro tested again.
You will find a new date stamped for each test.
Always look to the latest date for the + mark to see if the tank may still be filled to the 10% overfill. If the + is not there, the tank may only be filled to the pressure stamped on the tank.
"20#C02" C02 capacity
"TW24.9" Tare weight (LBS)
Some notes on other markings you may find on tanks.
There has been a common controversy over the original date on the scuba tank.
One group says it is the date of manufacture and the other group insists it is the date of the first hydrostatic test of the tank.
The truth is that it is both. Federal law requires that every high pressure tank be given a hydro test when it is made and before it can be sold.
You may find other markings that are optional.
For example, the test pressure of a tank might be shown as "TP4500", meaning that the test pressure is 4500 psi. It is 1.5 times the working pressure.”
cheers
sankar