What Is PEX Piping?

You asked the following question: “The pipe and tubing allowed by NFPA 13D says that as long as the material is listed in Tables 5.2.2 and 5.2.5, it is acceptable. PEX piping is not listed in either of the tables. However, the handbook lists a table in the annex as A.5.2.2(b). Does this indicate that PEX is allowed by NFPA 13D to use in any system configuration? As mentioned in the standard, a material may be specifically listed, however, if it is listed in the tables, it needs no listing.” In response to your question we have reviewed NFPA 13D, 2013 edition as the applicable standard. Our informal interpretation is that PEX has to be listed for fire protection and a stand-alone PEX piping system is permitted.

First, Section 5.2.3 does require PEX piping to be listed for fire protection applications. It states, “Types of pipe other than those specified in Table 5.2.2 shall be permitted to be used …show more content…
In addition, Table A.5.2.2(b) doesn’t negate the listing requirement either. Annex A.5.2.2 says that the information in Table A.5.2.2(a) through Table A.5.2.2(d) is provided to assist in the determination of acceptable water availability. This does not override the requirement of Section 5.2.2. The PEX piping used that meets UL 1821 is likely listed for fire protection. The issue is the description noted from UL that states, “This category covers cross-linked polyethylene (PEX) pipe and fittings intended for use in multipurpose piping systems of