What type of gas is commonly used as an inert gas slug in piping systems?

Nitrogen is commonly used as an inert gas slug in piping systems due to its non-reactive nature and availability. It does not support combustion and does not react chemically with most substances, making it ideal for use in various industrial applications, including piping systems where safety and chemical stability are a priority.

Nitrogen's low cost and abundance in the atmosphere further enhance its utility as an inert filler or slug for displacing oxygen and preventing unwanted reactions, especially in applications where flammable gases are present. This characteristic is essential for maintaining safety and preventing potential hazards during operation and maintenance of gas pipelines.

While other gases like helium and argon are also inert, they are either less available or more expensive compared to nitrogen, making nitrogen the preferred choice in many applications. Carbon dioxide, while also inert under certain conditions, is not suitable for use as a slug gas due to its potential reactive nature with certain materials and its role as a greenhouse gas.