Siphonic Roof Drainage Systems Design Standard Opens for First Public Review

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Chicago — A new American National Standard to provide design and installation requirements for siphonic roof drainage systems is being developed by the American Society of Plumbing Engineers (ASPE). ASPE 45: Siphonic Roof Drainage, a standard that was first published in 2007, has gone through extensive revision using the ASPE standards development process accredited by the American National Standards Institute. The draft revisions are now open for public comment until 11:59 CDT on March 24, 2013. To view the draft standard and submit a comment, visit

ASPE 45 establishes the minimum performance specifications for siphonic roof drainage systems and is intended to provide designers, installers, and code officials with a standard of practice for the proper application of siphonic roof drainage by:
•  defining the terms and parameters involved in the proper design of siphonic roof drainage systems,
•  describing the design procedures and calculations required for siphonic roof drainage systems,
•  describing the acceptable materials to be specified for use in siphonic roof drainage systems, and
•  providing guidelines for the inspection and testing of siphonic roof drainage installations.

ASPE 45 applies to engineered siphonic roof drainage systems intended to prime and operate full-bore through proper pipe dimensioning and the use of siphonic roof drains. It does not apply to conventional roof drains covered under ANSI/ASTM A112.6.4, atmospheric roof drainage systems, or sanitary drainage systems.

For more information on ASPE’s Standards Development Program, visit

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