Which of the following materials is acceptable for use in a sprinkler system piping under NFPA 13, 2017 edition?

The use of multiple materials in a sprinkler system piping is governed by NFPA 13, which outlines the standards for the installation of sprinkler systems. Under the 2017 edition of NFPA 13, various materials are indeed acceptable depending on the specific application, the environmental conditions, and the requirements of the installation.

Steel is commonly used for its strength and durability, as it can withstand high pressures and extreme temperatures. It is often used in commercial and industrial settings.

PVC, or polyvinyl chloride, is also allowed in specific conditions, particularly for certain types of wet pipe systems. It is lightweight, resistant to corrosion, and easier to install in some circumstances. However, its use is typically limited to certain temperature ranges.

Copper is another viable option due to its excellent corrosion resistance and long lifespan. It is often used in residential systems and can be advantageous in non-combustible environments.

Since all three materials meet the safety and operational requirements outlined in NFPA 13, their acceptance for use in sprinkler system piping reflects the diversity of materials available to meet the various needs of different building types and fire protection strategies. Thus, the correct answer acknowledges the multiple acceptable materials listed in the standard.