Kindly clarify Black steel pipe can be used in the foam concentrate line?
As per NFPA 16 2019 Clause 6.7.2.1
Foam concentrate pipe and valve shall me made of one of the following materials
1.Brass
2.Bronze
3.Stainless steel (304 or 316)
4.Other materials accordance with manufacturer certification and approved by AHJ
Black steel pipe is the preferred material for foam concentrate pipelines.