Rubber Gasketed Fittings for Fire-Protection Service

Sprinkler Outlet Passageway Test (15A): As originally proposed by UL on August 25, 2021, this test adds minimum waterway dimensions for side outlet fittings for connection to sprinklers and a test to verify the dimensions. After further review, the current published minimum passageway dimensions align with the nominal inside diameter of Schedule 40 pipe, as opposed to the minimum allowable inside diameter. Given that schedule steel pipes are commonly manufactured to the ASTM A53 specification, the minimum allowable tolerances from this standard should be taken into consideration. It should also be made clear that schedule pipe is only dimensionally defined by its outer diameter, wall thickness, and weight per length, including tolerances. This means the inside diameter is a “floating” reference dimension, not specified as a hard requirement in ASTM A53. In consideration of this, the updated dimensions in Table 15A.1 are being proposed to align with the theoretical minimum inside diameters, as calculated using the max./min. material and weight per length conditions allowed per ASTM A53. Additionally, and for further substantiation, actual measurements have been taken of the inside diameters of commercially available ASTM A53 Schedule 40 pipe. The findings show that in many cases the inside diameters fall below the currently published minimum passageway diameters, meaning these pipes, which are commonplace on the market today, will not permit a steel ball of the current published dimensions to pass through. For these reasons, we are proposing these changes to the minimum outlet passageway dimensions to align with the theoretical minimum inside diameters of Schedule 40 pipe per each size. We believe this more closely aligns with the actual allowable pipe conditions, while continuing to provide a practical means of quickly evaluating the outlet passageway dimensionally, prior to subjecting the product to Section 16 performance-based testing for K-factor flow characteristics.  Side Outlet Flow Characteristics for Sprinkler Connections Test (16): Rubber gasketed outlet fittings are often designed for use with sprinklers of a specific nominal K-factor or less. The intent of this proposal is to provide a means to limit usage of an outlet fitting to the maximum nominal K-factor sprinkler for which with the fitting was designed for use. Precedence has been established with the existing language of Sections 16.1 and 20.1(f) for ½” outlets where the nominal sprinkler K-factor can be limited to K8.0. This proposed revision is intended to expand upon this methodology to allow any outlet size to be limited to a maximum allowable K-factor sprinkler.