The most commonly used steel pipe for sprinkler systems is black steel pipe. Copper tubing is another piping material listed for sprinklers in NFPA 13. Also, plastic pipe (namely, CPVC and PEX tubing) is permitted for certain types of sprinkler systems.
Editor’s Note: “Back to Basics” is a column that will run periodically in PM Engineer reviewing the basic principles of plumbing engineering. This month’s article takes a closer look at the most common types of sprinkler pipe.