Protecting Your Gassets
A proper gas sampling and control system is essential to safe and efficient gas delivery

Read the Full Article in the September Issue of Lab Manager Magazine

Selecting the material of your piping system must start with considering the properties of the gas it is intended to transport and the process it is intended to support. When it comes to instrumentation and process gases, maintenance of purity is a key requirement. It does little to purchase high-purity grade instrumentation gases if they are contaminated by the pipeline. All materials selected should be cleaned to a very high level, delivered to the site capped, and installed by persons capable of maintaining that level of purity. If the piping material is copper tubing or pipe it should be at least “Cleaned for Oxygen Service,” a standard that guarantees that it is as free of hydrocarbon contamination as possible and safe for use in oxygen piping systems. In the case of stainless steels like 316L or more exotic alloys, “Electropolishing” may be desired, but it is not required.

For inert or non-reactive gases, copper was once an attractive, less expensive option. But with the increase in the price of copper and the higher installation costs because of the need to purge the system, while the joints are silver brazed, copper installations are now as expensive as those using 316L stainless.

The advantages of using stainless steel tubing are many. It is generally suitable for corrosive or reactive gases, the leak integrity of compression fitting joints or orbitally welded joints is far superior, and the installation costs less. For extremely corrosive or reactive sample or process lines, high nickel alloys like Monel^® or Hastelloy^® are desired if not required. Their high cost is outweighed by the durability of the installation and the improvement in safety.

Source:  Larry Galagher; Lab Manager Magazine