The information provided in this standard guide is intended for use by designers and specifiers of siphonic roof drainage systems and their related components. Specifically, this guide addresses the use and limitations of plastic pipe and fittings in siphonic roof drainage systems where internal operating pressures are typically sub-atmospheric.

1.1 This guide covers design and installation considerations for plastic siphonic roof drain systems for industrial, commercial, public, and residential buildings. Requirements for materials, pipe, and fittings are included.

1.2 The interchangeability of pipe and fittings made by different manufacturers is not addressed in this guide. Transition fittings for joining pipe and fittings of different manufacturers is provided for in the referenced pipe and fitting specification.

1.3 In referee decisions, the SI units shall be used for metric-sized pipe and inch-pound units for pipe sized in the IPS system (ANSI B36.10). In all cases, the values given in parentheses are for information only.