Crown Markings of a Standard SCUBA Cylinder

The U.S. Department of Transportation (DOT) and Canada’s Transport Canada (TC) require that cylinders made in compliance to their specifications be marked on the crown with certain information. Over the years the format used by Catalina Cylinders and Catalina East Division to display these markings has changed. Shown below is an example of the current crown markings stamped on the standard S80 (80 cu ft, 3000 psi) SCUBA cylinders manufactured at Catalina Cylinders, Garden Grove, CA. Under the example of the crown marking is a list of each of the specific crown markings followed by a brief explanation of that marking. The descriptions of the markings are the same regardless of the different stamping formats used over the years.
Example of the crown marking on an S80 SCUBA Cylinder:

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).

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