Crown Markings of an Industrial Gas Cylinder


The Department of Transportation (DOT) and Transport Canada (TC) require that a cylinder made in compliance with 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 a few times. Shown below is an example of the current crown marking stamped on the standard industrial gas I150 cylinders (150 cuft 2015 psi) manufactured by Catalina Cylinders, Garden Grove, CA. Under the example of crown marking is a list of each of the specific crown markings followed by a brief explanation of that marking. The information provided by the markings is the same, regardless of the different stamping formats used by Catalina Cylinders and Catalina East Division over the years.

Example of crown marking of an “I150” cylinder manufactured at Catalina Cylinders:

DOT-3AL2015..EBXXXXXXX M4002 07C08 I150 U18 TC-3ALM139

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).
2015 The service pressure “2015”, in pounds per square inch (psi), of the cylinder (required mark).
EBXXXXXXX The serial number of the cylinder. The serial number prefix of “EB” is specific to the 150 cuft 2015 psi industrial gas cylinder, manufactured at Catalina Cylinders, Garden Grove, CA facility, followed by a seven digit number (required mark).
M4002 The DOT Manufacturers Number (M-Number) “M4002” issued to Catalina Cylinders, Garden Grove, California facility (required mark).
07C08 The original hydrostatic test date of the cylinder, month “07” followed by the year “08“, performed at the time of manufacture of the cylinder. The “C” 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.
I150 The cylinder identifier. Identifies the cylinder is designed for the industrial gas service “I” a capacity of 150 cuft “150” of gas charge, hence I150.
U18 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).
139 The service pressure “139” (in bars) of the cylinder (required mark).


Posted in: Industrial