The American Society of Plumbing Engineers (ASPE) is pleased to announce that ASPE/ANSI 45-2025: Siphonic Roof Drainage was approved as an American National Standard by the American National Standards Institute (ANSI) on May 5, 2025.

ASPE/ANSI 45-2025 applies to engineered siphonic roof drainage systems designed to prime and operate full bore through proper pipe dimensioning and the use of siphonic roof drains. The standard establishes minimum performance specifications for systems, offers guidelines for inspection and testing, and outlines the design basis for siphonic roof drainage systems.

Copies of ASPE/ANSI 45-2025 are available for purchase as an eBook through ASPE’s Bookstore.

Last updated in 2018, the standard underwent an extensive revision process conducted in accordance with ASPE’s ANSI-accredited standards development procedures. Input was incorporated from across the plumbing design industry. Working Group 45 devoted significant time to refining the standard based on public comments and feedback from ASPE’s Main Design Standards Committee, ensuring alignment with current industry regulations.

ASPE extends its appreciation to the members of Working Group 45 for their dedication to the revision of this standard:

• Chair: Jay Stenklyft, UV-System Inc.

• Dennis Cavallaro, CPD, LEED AP, Southland Industries

• Brennan Doherty, MIFAB

• Peter Kraut, PE, South Coast Engineering Group Inc.

• Baalaganapathy Manohar, PE, CPD, LEED AP, SSOE Group

• John McNicol, Rainwater Technologies Ltd.

• John Rattenbury, PE, LEED AP, R. G. Vanderweil Engineers LLP

• Bill Ross, HydroMax Inc. Ltd.

• Christopher Rylant, Jay R. Smith Mfg. Co.

• David Weisz, PE, UV-System

ASPE has been an ANSI-accredited standards development organization since 2012. All ASPE standards are developed and published in accordance with the ANSI-approved Procedures for ASPE Design Standards Development. More information about ASPE’s standards development program is available at aspe.org/publications-news/standards.