CSLB Class B General Contractor's License Practice Exam

Which type of piping is sleeved when placed in concrete?

1. Metal pipe

2. PVC pipe

3. PEX tubing

4. HDPE tubing

The correct answer is: PEX tubing

In construction, when piping is embedded in concrete, it’s important to protect the piping from potential damage due to the chemical composition of the concrete and to allow for some movement, expansion, or thermal contraction that may occur. PEX tubing is often sleeved when placed in concrete for several reasons. PEX (cross-linked polyethylene) has a high degree of flexibility and can expand when exposed to cold temperatures and shrink when it warms. Sleeving provides additional protection against the physical stresses exerted by the concrete as it cures, preventing abrasion and maintaining the integrity of the pipe. Additionally, sleeve materials may work as barriers to protect PEX from direct contact with moisture or soil contaminants. Moreover, because PEX is not as rigid as metal pipes or other materials, sleeving allows for the necessary space for potential movement without risking the integrity of the connection points. This process helps to prevent structural damage that could occur due to settling, shifting, or the natural expansion and contraction of both the pipe and concrete. While other piping materials may also require protection, they may not need to be sleeved to the same extent as PEX when embedded in concrete, making PEX tubing the most suitable material for this particular application.