When manufactured, welding gas cylinders are guaranteed to safely store caustic welding gases for a limited time period. These heavy steel and alloy cylinders are designed to deliver highly pressurized flammable gases. These cylinders must be reevaluated, or “static tested” according to manufacturer's specifications in order to guarantee that the cylinders will remain integrity, and provide ongoing reliable service. Knowing how to identify manufacturers dating is essential to maintain gas cylinder safety.

Things You Will Need
  • Welding gas cylinder

  • Cylinder supplier's documentation

Identify the manufacturer's dating stamp. This stamp is typically located on the top portion of the cylinder, near the gauge and regulator. The standardized format for welding gas cylinders date stamps is "month — year;" as an example "4 – 55." The first number in the example, "4," is the month of manufacture. The second number the example, "55," is the year of manufacture. This date code will be stamped into the metal surface of the cylinder.

Identify if any subsequent dating stamps have been added to the cylinder. Each welding gas cylinder must be periodically tested and verified for safety. These testing procedures must be completed regularly, based on the contents of the welding gas cylinder.

Check manufacturer's documentation, and industry standards to determine the length of time allowed between welding gas cylinder certifications.


The types of welding gases include: flammable, flammable liquid, nonflammable, corrosive, poison and oxidizer. The gas cylinders for each of these gas types are required to be retested at various intervals during the cylinders lifetime. Testing intervals vary based upon the properties of the gas.


Welding gas cylinders should never be used if the tank is outside of appropriate dating guidelines. To do so can risk a catastrophic failure, or explosion when the tank is used.