If the pipes are laid along the walls in an open way, then the casing is most likely not needed. However, if it is necessary to lay the highway through building structures, for example, through screeds, then you can not do without a protective casing.
Protective corrugated casing performs two main functions: 1. Provides temperature fluctuations in the lengths of the pipes, being a kind of spatial buffer. 2. Allows you to repair and replace pipes without dismantling engineering structures.
When using a corrugated casing does not follow: 1. Supply water or gas. 2. Use it in the hydraulic system of warm floor.
The use of a corrugated casing today is not a squeak of fashion, but a modern solution caused by the necessity. Today, repairs are a flexible repair that allows you to make adjustments after a change in needs. Modern technologies allow you to lay up to six pipes in one casing in one casing.