There are a series of AWWA C2XX standards including AWWA C200 for steel water pipes, couplings and many different coating and lining systems. However, I don't believe steel pipe was really approved for underground fire protection service per e.g. NFPA 24 standard until the early 2000's (when I believe steel was conditionally petitioned in). I don't know the reasons for this; however, I do know small diameter (less than man-entry size) steel piping may be generally less available with combinations of e.g. durable for long-term water service Shop applied cementlinings and field joining systems designed to work with same, than are say ductile iron piping long listed per NFPA 24 for such service. In any case, piping should be appropriately certified or listed by the manufacturer for such service, and NFPA 24 standard in any case contains many requirements that should be understood for design and construction of serviceable systems.
