Overview
ASTM F2021-17(2022): Standard Guide for Design and Installation of Plastic Siphonic Roof Drainage Systems provides essential guidance for the design and installation of siphonic roof drainage systems utilizing plastic pipes and fittings. Developed by ASTM International, this standard targets professionals involved in specifying, designing, and implementing siphonic drainage solutions for a variety of building types, including industrial, commercial, public, and residential structures.
Siphonic roof drainage systems employ specially designed roof drains and piping arrangements that allow water to flow at high velocity under sub-atmospheric (negative pressure) conditions, enabling efficient drainage without requiring pipe gradients. This standard highlights the use, selection, and limitations of plastic materials in such technically advanced systems, ensuring safe, efficient, and code-compliant installations.
Key Topics
- Material Requirements: Specifies appropriate plastic materials such as Poly(Vinyl Chloride) (PVC), Acrylonitrile-Butadiene-Styrene (ABS), and Polyethylene (PE) for use in siphonic roof drainage. Only solid-wall pipes of Schedule 40 or greater are recommended for sub-atmospheric conditions.
- Design Considerations: Addresses requirements for pipe sizing, wall thickness, supports, hangers, and bracing, referencing governing plumbing and building codes such as the International Plumbing Code (IPC), Uniform Plumbing Code (UPC), and NFPA 5000.
- Thermal Expansion: Guidance on accounting for contraction and expansion due to temperature variations, including the use of telescoping expansion joints that maintain system integrity under changing conditions and through fire-rated barriers.
- Fire Protection: Specifies appropriate fire stopping techniques and assemblies for plastic piping where system penetrations occur through fire-rated walls or floors, referencing ANSI/UL 1479 and relevant ASTM test methods.
- Connections & Fittings: Outlines preferred connection methods (e.g., threaded adaptors) for reliable integration of piping to siphonic roof drains and details requirements for reducers and increasers in both horizontal and vertical orientations.
- Inspection and Testing: Verification of correct material installation and pressure testing under hydrostatic conditions form critical parts of system commissioning. Compressed air should not be used for pressure testing.
- Reference to Regulatory Codes: Aligns installation standards with prevailing local and international codes to ensure compliance with fire resistance and performance requirements.
Applications
This standard serves as a key resource for:
- Plumbing and building designers seeking efficient roof drainage solutions in large or complex roof structures
- Specifiers and contractors engaged in the installation of plastic piping in siphonic systems
- Facility managers and building owners pursuing cost-effective and reliable rainwater management
- Code authorities reviewing compliance with safety and performance requirements
Practical applications are found across a range of building types, from high-rise commercial developments and industrial facilities to educational, healthcare, and residential buildings. The use of plastic piping enhances corrosion resistance, reduces system weight, and often improves installation efficiency compared to metal alternatives.
Related Standards
To ensure the correct design and installation, ASTM F2021-17(2022) references several important related standards, including:
- ASTM D2665, D2949, D3034, F714, F1901 - Specifications for various types of PVC and PE plastic drain, waste, and vent pipes and fittings
- ASTM F412, D1600 - Terminology for plastic piping systems
- ASTM E84, E814, E1966, E2393 - Test methods and practices for fire resistance and stopping assemblies
- ANSI/ASME A112.6.4, A112.6.9 - Standards for roof drains and siphonic roof drains
- International Plumbing Code (IPC), Uniform Plumbing Code (UPC), International Building Code (IBC), NFPA 5000 - Governing building and plumbing codes
For compliance, designers and installers should coordinate closely with these standards and associated local regulatory requirements.
Keywords: siphonic roof drainage, plastic drainage systems, ASTM F2021, PVC pipe, ABS pipe, polyethylene pipe, fire stopping, roof drain installation, drainage system design, building plumbing standards.