Waterless trap seals solve a well-documented building performance problem: P-traps that dry out in low-use drains, allowing sewer gas, odors, and pests into occupied spaces. But specifying them correctly in construction documents requires understanding where they fit in the CSI framework, what certifications to require, how to size them for different drain bodies, and what submittal documentation to expect from manufacturers.
This guide is written for architects, mechanical engineers, and specification writers who need to incorporate waterless trap seal devices into project documents. It covers the specification language, the relevant standards, and the practical decisions you will encounter during design and construction administration.
Where waterless trap seals fit in the specification
Waterless trap seal devices are plumbing accessories that install inside existing or new floor drain bodies. They are not drain bodies themselves, not backflow prevention devices, and not part of the piping system. Understanding this classification is essential for correct specification placement.
CSI MasterFormat placement
Under CSI MasterFormat 2018, waterless trap seals most commonly appear in one of two locations:
- Section 22 13 16 - Sanitary Waste Piping Specialties: This is the most technically precise location. Trap seal devices are specialties that augment the sanitary waste piping system. Most plumbing engineers place the specification here.
- Section 22 40 00 - Plumbing Fixtures: When the waterless trap seal is specified as an integral accessory to a floor drain assembly (e.g., "furnish floor drain with waterless trap seal device"), it may appear as a subsection or scheduled item under plumbing fixtures.
Both placements are accepted practice. The key is consistency: if you place the specification under 22 13 16, ensure the floor drain schedule in 22 40 00 cross-references it. If you specify the trap seal as part of the floor drain assembly in 22 40 00, ensure the plumbing engineer coordinates sizing and compatibility.
Specification tip: Regardless of CSI section placement, always include a performance requirement referencing ASSE 1072-2020 (Performance Requirements for Barrier Type Floor Drain Trap Seal Devices). This is the industry standard specifically written for waterless trap seal products and ensures the specified product has been independently tested.
Performance requirements to specify
A well-written specification defines the performance the product must achieve, not just the product name. For waterless trap seals, the critical performance requirements are:
Gas and odor seal
The device must create an airtight seal when no water is flowing through the drain. The relevant test standard is ASSE 1072-2020, which includes specific pass/fail criteria for gas retention under both static and dynamic conditions. Specify that the product must be tested and listed to this standard by an accredited third-party laboratory.
Flow rate
The device must not restrict water flow below the capacity of the drain body it serves. Flow rate testing per ASME A112.6.3 (Floor and Trench Drains) confirms the device does not create a bottleneck. Green Drain's 4-inch model is tested to 73 GPM, which exceeds the capacity of most 4-inch commercial floor drain bodies.
Durability
Specify a minimum cycle life for the valve mechanism. Green Drain is tested to 2,500+ open-close cycles without degradation in sealing performance. This translates to 10-25 years of service under typical commercial building conditions.
Material requirements
For the sealing element, specify medical-grade silicone or equivalent. This ensures chemical resistance to sewer gases (hydrogen sulfide, ammonia), cleaning chemicals, and biological compounds. Avoid specifications that allow generic rubber or elastomeric materials, as these degrade faster in drain environments.
Certification and listing requirements
The submittal documentation for a waterless trap seal should demonstrate compliance with multiple standards. Here is what to require and why each matters:
cUPC listing (IAPMO)
The Uniform Plumbing Code (UPC) requires plumbing products to be listed by an accredited agency. cUPC listing from IAPMO (International Association of Plumbing and Mechanical Officials) confirms the product has been evaluated against applicable UPC requirements and is accepted for installation in UPC jurisdictions across the United States and Canada. This is the foundational listing for code compliance.
ASSE 1072-2020
This is the performance standard specifically written for barrier-type floor drain trap seal devices. It covers gas seal testing, flow rate testing, durability testing, and installation requirements. Requiring ASSE 1072 certification ensures the product has been independently tested to a standard designed specifically for this product category.
NSF/ANSI certifications
Depending on the building type and drain location, additional NSF certifications may be required:
- NSF/ANSI 2 (Food Equipment): Required for drains in food preparation, food service, and food processing areas. This certification confirms the materials and construction are suitable for environments where food safety is regulated. Specify this for restaurant, cafeteria, and commercial kitchen drains.
- NSF/ANSI 61 (Drinking Water System Components): Required when the device may contact potable water. This certification confirms no harmful substances leach from the product. Relevant for drains connected to or near potable water systems.
HACCP International
For food manufacturing and processing facilities that operate under HACCP (Hazard Analysis and Critical Control Points) food safety management systems, HACCP International certification provides additional assurance that the product meets food safety requirements. This is increasingly requested by food industry clients and their auditors.
Green Drain holds 13 certifications including all of the above. Complete certification documentation is available for download on the specifications page and can be included directly in project submittals.
Sizing guide for different drain bodies
Waterless trap seals are sized to the internal diameter of the drain body, not the pipe size below or the grate size above. This is a common source of confusion during specification and submittal review. The drain body internal diameter is typically one nominal size larger than the outlet pipe.
Available sizes
- GD2 (2-inch): Fits drain bodies with a 2-inch internal diameter. Common applications include condensate drains, small fixture drains, and lavatory waste connections. Typical pipe size below: 1.5 inches.
- GD3 (3-inch): Fits 3-inch drain bodies. The most common size for standard restroom floor drains, corridor drains, and light-commercial applications. Typical pipe size below: 2 inches.
- GD4 (4-inch): Fits 4-inch drain bodies. Standard for commercial kitchens, healthcare facilities, mechanical rooms, and most industrial floor drains. Typical pipe size below: 3 inches. This is the most frequently specified size for new construction.
- GD6 (6-inch): Fits 6-inch drain bodies. Used in large-format industrial drains, trench drains, and high-capacity commercial applications. Typical pipe size below: 4 inches.
Sizing notes for specifications
When writing the specification, include language that requires the contractor to verify drain body internal diameter before ordering. Drain bodies from different manufacturers can vary slightly in internal dimensions even at the same nominal size. Green Drain's compression-fit design accommodates normal manufacturing tolerances, but field verification avoids delays during installation.
For projects with multiple drain sizes, include a schedule that maps each drain location to the appropriate trap seal size. This is especially important in healthcare facilities and university campuses where a single project may include 2-inch, 3-inch, and 4-inch drains across different areas.
Writing the specification section
A complete specification section for waterless trap seals should include the following parts:
Part 1 - General
Define the scope (waterless trap seal devices for floor drains), reference standards (ASSE 1072-2020, ASME A112.6.3), and submittal requirements. Require product data, certification certificates, and installation instructions as part of the submittal package.
Part 2 - Products
Specify the performance requirements (gas seal, flow rate, cycle life, material), the required certifications (cUPC, ASSE 1072, NSF as applicable), and the acceptable manufacturers. If writing a proprietary specification, name the product. If writing a performance specification, define the requirements and allow substitutions that meet all listed criteria.
Include sizing requirements by referencing the drain schedule or specifying that the trap seal device shall be sized to fit the drain body specified in Section 22 40 00.
Part 3 - Execution
Installation of waterless trap seals is straightforward: remove the drain grate, insert the device, replace the grate. Specify that installation shall be per manufacturer's instructions. Include a requirement for the contractor to verify drain body compatibility before installation and to demonstrate proper function (water flow through the valve) after installation.
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Coordination with other specification sections
Waterless trap seals interact with several other specification sections. Ensure coordination in the following areas:
- Section 22 40 00 (Plumbing Fixtures): The floor drain schedule should indicate which drains receive waterless trap seals. If the trap seal is specified separately in 22 13 16, add a cross-reference note.
- Section 22 05 00 (Common Work Results for Plumbing): Include waterless trap seals in the general plumbing submittal schedule.
- Section 23 00 00 (HVAC): HVAC condensate drains that connect to the sanitary system may require trap seals. Coordinate with the mechanical engineer to identify these locations.
- Division 01 (General Requirements): If the project has sustainability or water conservation goals, waterless trap seals contribute to water savings by eliminating the need for trap primers. Reference this in the sustainability narrative if applicable.
Submittal review checklist
When reviewing contractor submittals for waterless trap seals, verify the following:
- cUPC listing certificate from IAPMO confirming the product is listed for use as a trap seal device
- ASSE 1072-2020 test report from an accredited laboratory confirming gas seal, flow rate, and durability performance
- NSF certification (NSF/ANSI 2 for food-service areas, NSF/ANSI 61 for potable water contact) as applicable to the project
- Product data sheet with dimensions, materials of construction, and flow rate data for each specified size
- Installation instructions confirming the device fits the drain bodies specified on the project
- Sizing confirmation from the contractor or manufacturer verifying compatibility with the specific drain bodies scheduled
Green Drain provides a complete submittal package that includes all of the above documents in a single download. For project-specific sizing assistance or custom submittal preparation, contact the Green Drain specification team.
Common specification questions
These are the questions that come up most frequently during specification writing and construction administration for waterless trap seals.
Can waterless trap seals be specified for new construction and retrofit?
Yes. The same product works in both applications. For new construction, the trap seal is specified as part of the floor drain assembly and installed during plumbing rough-in or finish. For retrofit, the trap seal drops into the existing drain body with no modification to the drain, the piping, or the surrounding construction. This makes them suitable for both new projects and renovation specifications.
Do waterless trap seals replace the P-trap?
No. The P-trap remains in the piping system as required by plumbing code. The waterless trap seal is an additional barrier device that provides protection when the P-trap's water seal evaporates. Think of it as a backup seal that works regardless of water presence. The P-trap continues to function when water is present; the waterless trap seal takes over when it is not.
Are waterless trap seals accepted by code officials?
Green Drain is cUPC listed and accepted by plumbing authorities in all 50 states. The state plumbing code guide provides jurisdiction-specific details. For projects in jurisdictions that have adopted the International Plumbing Code (IPC) rather than the Uniform Plumbing Code (UPC), the cUPC listing and ASSE 1072 certification provide the basis for acceptance. In practice, code officials rarely reject a cUPC-listed product.
How do I specify trap seals for drains in healthcare infection control areas?
For healthcare facilities, specify waterless trap seals for all floor drains in patient care areas, particularly those in low-use locations (storage rooms, corridor drains, mechanical rooms adjacent to patient areas). Reference the CDC/HICPAC guidelines on environmental infection control and note that the waterless trap seal addresses the specific risk of dry-trap pathogen transmission. Include coordination notes with the infection control risk assessment (ICRA) for the project.
Frequently asked questions
How do I specify waterless trap seals?
Waterless trap seals are typically specified under CSI MasterFormat Section 22 13 16 (Sanitary Waste Piping Specialties) or Section 22 40 00 (Plumbing Fixtures). The specification should reference ASSE 1072 performance requirements, require cUPC listing, and include submittal requirements for product data, certifications, and sizing documentation.
What CSI section covers trap seals?
Waterless trap seal devices fall under CSI MasterFormat Division 22 (Plumbing). The most common placement is Section 22 13 16 (Sanitary Waste Piping Specialties). Some specifications place them under Section 22 40 00 (Plumbing Fixtures) when specified as an accessory to floor drain assemblies. Both placements are accepted practice.
What submittals are needed for waterless trap seals?
Standard submittals include: cUPC listing certificate from IAPMO, ASSE 1072-2020 test report, NSF/ANSI certification as applicable, product data sheets with dimensions and flow rates, and installation instructions. Green Drain provides a complete submittal package available on the specifications page.
What sizes are available for waterless trap seals?
Green Drain is available in four standard sizes: 2-inch (GD2), 3-inch (GD3), 4-inch (GD4), and 6-inch (GD6). Sizes correspond to the internal diameter of the drain body. The 3-inch and 4-inch models cover the majority of commercial and institutional floor drain applications.