A new section of the 2019 edition of NFPA 13 (126.96.36.199.2) specifically states that nonmetallic piping, including CPVC, may be used in fire sprinkler systems in private garages within a dwelling as long as the garage space:
Does not exceed 1,000 square feet, and
Is protected by the appropriate wall or ceiling sheathing.
This clarifies what some considered to be a limiting factor, where the standard stated that nonmetallic piping is permitted for use in light-hazard areas and in ordinary-hazard rooms not exceeding 400 square feet. Some AHJs interpreted that point to permit only metallic pipe in residential garages exceeding 400 square feet, even if the rest of the system is constructed from CPVC.
Designers, specifiers, building owners and contractors who wanted to use CPVC for fire sprinkler systems in garage construction may have been hampered by the interpretation. They’re now backed by a code specifically outlining CPVC usage.
Code Clarification Means Uniformity, Offers an Alternative for Most Construction
The revision matches NFPA 13 with NFPA 13R and the International Building Code, including treating those garages as part of the dwelling unit and not as a separate occupancy subject to stricter standards.
So, what size garage does the new section cover? A 2016 Builder Magazinearticle comparing square footage costs in home building provides a factoring square footage for a three-car garage at 700 square feet. Thus, it’s a safe bet that most of the residential garages being built or retrofitted in North America can utilize CPVC for fire protection.
That’s not to say that CPVC may be used in all garage applications. Larger automobile parking garages – over 1,000 square feet – remain ordinary-hazard group 1 occupancies, requiring metallic piping for sprinkler systems.
This is an excellent opportunity for all that’s been a long time coming. Codes are written for the protection of all concerned and, certainly, interpretations should err on the side of caution. We applaud the NFPA in its evaluation of NFPA 13 and the revised section that literally opens the door for CPVC in residential garage fire protection systems.