These requirements cover the construction and performance of Grooved and Plain End fittings intended to be joined to pipe or to another fitting by couplings complying with the requirements of the Standard for Rubber Gasketed Fittings for Fire-Protection Service@ UL 213. For the purpose of this Outline of Investigation@ Grooved and Plain End fittings include constructions having one piece cast devices and fittings fabricated from steel pipe that could be segmented and welded to form the fitting.