What does the marking 4B195 indicate about pressure and hydrostatic testing?

What does the marking 4B195 indicate about pressure and hydrostatic testing?

• A. 195 is the normal pressure, and the cylinder can be hydrostatically tested to 585 psi.
• B. 195 is the maximum pressure; the cylinder never requires hydrostatic testing.
• C. It indicates a 195 liter capacity with no testing requirement.
• D. It is a model number unrelated to pressure.

Answer: (A)

The marking encodes how much internal pressure the cylinder is designed to handle and the pressure used for hydrostatic testing. The number 195 is the service pressure in psi—the normal operating pressure the cylinder is filled to. The hydrostatic test pressure shown is 585 psi, which is three times the service pressure, meaning the cylinder must withstand that higher pressure during the hydrostatic test. The prefix 4B identifies the cylinder type/construction, not its capacity or model. So, 195 is the normal operating pressure, and the cylinder can be hydrostatically tested to 585 psi.

The marking encodes how much internal pressure the cylinder is designed to handle and the pressure used for hydrostatic testing. The number 195 is the service pressure in psi—the normal operating pressure the cylinder is filled to. The hydrostatic test pressure shown is 585 psi, which is three times the service pressure, meaning the cylinder must withstand that higher pressure during the hydrostatic test. The prefix 4B identifies the cylinder type/construction, not its capacity or model.

So, 195 is the normal operating pressure, and the cylinder can be hydrostatically tested to 585 psi.