sprinklernotes
Galvanized Piping Requirements for Dry and Preaction Sprinkler Systems
You asked the following questions: “We have an attic protected by a dry system using Viking Attic Sprinklers. Will this system be required to be galvanized per 8.4.7.2.1?” In response to your question, we have reviewed NFPA 13, 2010 edition as the applicable standard. Our informal interpretation is that internally galvanized steel piping is not required on dry pipe and preaction systems using other than CMSA sprinklers and other situations noted below. Section 8.4.7 of NFPA 13 addresses special requirements for CMSA sprinklers. Sections 8.4.7.1 and 8.4.7.2.1 are subsections of 8.4.7 and set requirements that only apply to the use of CMSA sprinklers and do not apply to any other sprinkler types. Thus, NFPA 13 does not require galvanized pipe for all dry pipe and preaction systems. There is some misconception that all dry pipe and preaction systems are required to have galvanized piping. Dry pipe and preaction systems can be black steel except for a few applications. The dry pipe and preaction system piping must be corrosion resistant or internally galvanized when small orifice K-factor 4.2 sprinklers protect light hazard occupancies according to Section 8.3.4.3. Water-cooling towers under the Special Occupancy Requirements Chapter in Section 21.21.2.10.1 require the piping, fittings, hangers, braces, and attachment hardware including fasteners shall be hot-dip galvanized steel or use other materials that have a superior corrosion resistance. Two other sections that require galvanized pipe are Section 6.9.3.3 that requires all piping to water motor-operated devices shall be galvanized or brass or other corrosion-resistant material acceptable under this standard, and Section 6.9.3.4 that piping between the sprinkler system and a pressure-actuated alarm-initiating device shall be galvanized or of nonferrous metal or other approved corrosion-resistant material. Thus, there is no carte blanche requirement that all dry pipe and preaction systems must have galvanized piping.
