Frequently Asked Questions

Loosen the stainless steel clamps (don't remove them), slide the coupling over the plain spigot ends of both pipes, then tighten the clamps. For most standard couplings, torque to 60 in-lb. Pressure test before backfilling or concealing the joint.

See our Installation Instructions page for product-specific guides and videos.

Torque varies by product. Most standard couplings tighten to 60 in-lb. High-torque band products take a higher spec, so check the installation instructions for your product. Some under-sink connectors are hand-tighten only.

A few things to try:

• Confirm the coupling is the right one for your pipe type and size (sizing is OD-based, not nominal).
• Check that pipe ends are clean and free of burrs or flaring.
• Apply a small amount of soapy water to the pipe, not the coupling. Soaping the coupling itself makes it hard to grip.
• Make sure the clamps are fully backed off.
• A gentle tap with a rubber mallet can help seat it.

Yes, where your local code allows it. Many local codes accept standard couplings below ground. For buried joints, we recommend a Strong Back RC shielded coupling for shear resistance.

Yes. Pipes must be properly supported on both sides of the coupling per code. Unsupported pipe can sag at the joint, creating a low spot that traps debris and causes backups.

No special tools required. Pull the toilet and scrape off any old wax. Clean the toilet horn with rubbing alcohol, peel the liner and press the FTS wax-free seal onto the horn. Wet the ribs with soapy water and set the toilet.

Yes, for remodels. The seal stays on the toilet horn, so you can pull the toilet and set it back with the same seal. Check the ribs for damage before you reset it.

Yes. Fernco couplings join cast iron, PVC, ABS, copper, clay, concrete, steel and more, in same-size and reducing versions.

• Proflex: shielded, for above ground
• Strong Back RC: shielded, for below ground
• HULK: for below ground, reinforced with internal stainless steel shear rods (not a shielded coupling)
• Standard Couplings: a flexible option for everyday DWV repairs where your code accepts them

A standard coupling is a flexible PVC sleeve with stainless steel clamps. A shielded coupling adds a stainless steel band around the sleeve. The shield resists shear and holds the pipe ends in line, which matters below ground and on heavy stacks. For most jobs, we recommend shielded.

HULK is not a shielded coupling. It uses stainless steel rods inside the body instead.

No. Fernco flexible couplings are designed for gravity-flow drain, waste, and vent (DWV) systems only. They are not rated for pressurized water supply lines.

Most Fernco couplings are rated up to 140°F intermittent. Ratings can vary by product line, so for specifications on a particular coupling, refer to the product page or cut sheet for the exact series you're using.

Maximum test pressure is 4.3 psi (29.6 kPa). Fernco couplings are intended for gravity-flow DWV systems and are not for pressurized applications.

Standard Fernco couplings are made of elastomeric polyvinyl chloride (PVC) with 300-series stainless steel clamps. A few specialty couplings are made of rubber or neoprene depending on the application. Shielded couplings add a stainless steel shear band over the elastomer sleeve.

Fernco couplings are designed for permanent installation and last as long as a properly installed piping system.

Yes. Fernco's elastomer resists a wide range of chemicals commonly found in DWV systems. For specific chemical compatibility, refer to our Acid Resistance Chart.

Effective April 7, 2026, Fernco's core repair coupling families are AIS (American Iron and Steel) and BABA (Build America, Buy America) compliant, with every component sourced in the United States.

See the AIS and BABA page for the full list of compliant products and submittal documentation.

AIS stands for American Iron and Steel, a domestic sourcing requirement applied to certain federally funded water infrastructure projects.

BABA stands for Build America, Buy America, a broader domestic-content requirement under federal infrastructure funding. Both are commonly specified on public works and federally funded projects.

Submit a request through our AIS Compliance Letter Request form. Have your series, part number, and project information ready to speed up processing.

For most submittal packages, you'll want to include the AIS/BABA Scope List PDF, the relevant product cut sheet, and the compliance letter if your agency requires one.

Yes. Fernco couplings are tested and listed to applicable industry standards. For specific approvals, including ASTM, CSA, UPC and IPC listings by product series, see our Codes / Standards page. Always confirm acceptance with your local code authority.

Yes. The majority of Fernco products are manufactured in Davison, Michigan, Fernco's home since 1977. Building on that foundation, as of April 7, 2026 our core repair coupling families are now produced entirely from 100% U.S.-sourced components, reinforcing our long-standing commitment to American manufacturing.

Fernco couplings, connectors and seals are manufactured articles and do not need an SDS. SDS sheets for Fernco Infrastructure chemical products are on our Safety Data Sheets page.

Yes, on most products. Toilet Seals and StormDrain must be ordered in full box quantities.

Standard lead time is 2–3 business days for orders shipping FedEx Ground. Larger or freight orders may vary, so contact customer service for specifics.

Fernco has no general order minimum. A small number of items must be ordered in box quantities (Toilet Seals and StormDrain).

Fernco products are sold through plumbing wholesalers, distributors, and select retailers nationwide. Use our Where to Buy tool to find a source near you.

Fernco does not sell direct. We distribute through wholesalers and retailers to keep our pro-channel partners strong. Use the Where to Buy tool to find a local source, or call customer service at 1-810-503-9000 for distributor recommendations in your area.

Dimensional drawings and product spec sheets are available on each product page in the Resources section. For high-resolution images, branded promotional materials, or co-marketing assets, contact your Fernco sales representative or reach out through Contact Us.

A flap valve is a passive, one-way device installed at the open end of a stormwater pipe, culvert, or outfall. It lets water discharge through a hinged flap, then the flap swings shut to block water from flowing back into the system. In North America these are most often called flap gates, and also go by flap valve, tide gate or tidal flap (in coastal applications), non-return valve, one-way valve, and check valve. A duckbill valve is a related elastomeric style that serves the same backflow-prevention purpose.

Learn more on our Flap Valves product page.

No. They're different products for different jobs. A flap valve / flap gate mounts at the end of a stormwater pipe or outfall and uses a hinged flap to stop river, lake, or tidal water from backing up into the drainage system. A backwater valve is an in-line device installed within a building's sewer lateral to keep a surcharged municipal sewer from backing up into a home. Fernco flap valves are end-of-pipe stormwater outfall devices, not in-line sewer backwater valves.

The flap opens under normal forward flow to let stormwater discharge. When water levels rise downstream from heavy rain, a high river or lake, retention-pond surge or high tide, the higher outside pressure pushes the flap shut, sealing the pipe and preventing reverse flow into the protected area. Operation is automatic and requires no power.

Fernco flap valves are offered in 4", 6", 8", 10", 12", 14", 15", 16", 18", 20", 21", and 24", available in both wall mount and spigot mount configurations. For spigot mount models, confirm pipe OD and ID to ensure proper fit. See the Flap Valves product page for sizing and submittal documentation.

Fernco flap valves are built from corrosion-resistant high-molecular-weight polyethylene (HMWPE) body and backplate, with an EPDM seal, 316 stainless steel hardware, and glass-filled nylon hinges. Compared with traditional cast iron and metal flap gates, they're lightweight, corrosion- and chemical-resistant, easier to install, and lower-maintenance, while delivering long-term performance in harsh environments.

Fernco flap valves provide passive backflow protection for stormwater outfalls and drainage systems. Common applications include community flooding protection, municipal stormwater discharge where rivers, lakes, or retention ponds can rise, and coastal & tidal sites where the valve prevents tidal surge from entering the drainage system.

Fernco flap valves come in wall mount and spigot mount configurations. Wall mount fastens to a structure such as a headwall. Spigot mount connects using a Strong Back shielded coupling sized to the pipe OD, allowing connection to a wide range of pipe materials and sizes. Confirm pipe OD and ID to ensure proper fit.

Fernco flap valves are automatically operated and designed to be low-maintenance. Their corrosion-resistant HMWPE and 316 stainless steel construction avoids the rust and seizing common with metal flap gates. As with any flap gate, periodic inspection to clear debris and confirm the flap seats fully is recommended.

Fernco provides cut sheets, spec sheets, dimensional drawings (all sizes, both mounting styles), installation instructions, and engineer-ready submittal packages, plus selection support to help match size, mounting style, and site conditions. Find these on the Flap Valves product page, or start a selection-support request there for help specifying the right configuration.

Yes. Fernco launched its flap valve line in North America in June 2026 as part of the new Fernco Water Management portfolio. First introduced by Fernco UK in 2024 and proven in municipal and stormwater applications, the line is now available throughout the U.S. and Canada through Fernco and its authorized distribution partners. Use our Where to Buy tool to find a source.

Call 1-810-503-9000 or email us. Customer service hours are listed on our contact page.

Use our Rep Locator to find your local Fernco sales representative.

Yes. PipePatch is part of Fernco's Infrastructure product line. Visit the PipePatch product page for product information, applications, and resources.

Open positions and the application portal are on our Careers page. You can also reach out to our Human Resources team directly.

Contact us through Contact Us or call 1-810-503-9000 and ask for the sales team. We'll connect you with the right person based on your territory and channel.