In plumbing what is the purpose of the pipe sleeve?

In Plumbing, a pipe sleeve serves as a protective casing for pipes that pass through walls or floors. It helps prevent damage to the pipe from abrasion and movement, while also reducing the risk of leaks due to friction. Additionally, sleeves can aid in thermal insulation and can allow for expansion and contraction of pipes without causing stress. Overall, they enhance the durability and longevity of plumbing systems.