Extra strength
Resists heavy earth loads and shear forces in demanding underground applications.
Shielded flexible couplings
1000 Series
Fernco flexible sealing with a stainless steel shear ring, built for underground pipe transitions that face heavy earth loads and pipe movement.
Built for tough underground connections.
Strong Back RC combines Fernco flexible sealing performance with stainless steel reinforcement for a stronger buried transition.
Shielded support
A .012" stainless steel shear ring and molded-in bushing add stability to the joint.
Broad range
Connects clay, cast iron, plastic, concrete, ductile iron and steel underground piping.
Municipal sewerStorm drainUnderground repairNew constructionPipe transitionsHeavy earth loads
Reinforced for demanding pipe transitions.
Strong Back RC couplings are designed for pipe transitions where the outside diameters, pipe materials or jobsite conditions call for added alignment support. The molded-in bushing works with the stainless steel shear ring to keep the connection stable while the flexible elastomeric sleeve conforms to the pipe for a dependable seal.
Stainless steel clamps provide uniform compression, and the shear ring carries shear load so the joint holds alignment under backfill and settling.
Why shielded
Built to hold under load.
Buried couplings face earth loads, settlement and shear. An unshielded flexible coupling can deform and let the pipe pull out of line. The Strong Back RC stainless steel shear ring wraps the sleeve and keeps the joint rigid and aligned, so the connection holds where it is hardest to reach.
UnshieldedDeforms and shifts under load
Shielded RCShear ring holds the line
Specifications.
Coupling
- Standards
- ASTM C1173, CSA B602
- Installation torque
- 60 in-lbs (120 on 16" and larger)
- Maximum test pressure
- 4.3 PSI (29.6 kPa)
- Max operating temp
- 140° F non-consistent
Gasket
- Standards
- CSA B602, ASTM D5926, C1173
- Hardness
- Shore "A" 65 ±5
- Tensile strength
- 1000 psi min
- Elongation
- 250% min
- Brittleness
- -40° F
Clamp
- Housing
- 301 stainless steel
- Band
- 301 stainless steel
- Screw
- 305 stainless steel
Shear ring
- Material
- 300 series stainless steel
- Thickness
- .012"
- Widths
- 1.50", 2.13", 4"
Made in the USA
AIS & BABA details
AIS & BABA compliant.
1000 Series Strong Back RC couplings 15" and below are made in the USA and meet the American Iron and Steel and Build America, Buy America requirements for federally funded underground infrastructure.
Find your coupling.
Browse the 1000 Series pairings, or use the size finder to match the two pipes you are connecting.
1001Clay to ClayDrawings1002Clay to Cast Iron / Plastic / SteelDrawings1003Clay to Ductile IronDrawings1004Concrete to ConcreteDrawings1005Concrete to ClayDrawings1006Concrete to Cast Iron / Plastic / SteelDrawings1051Ductile Iron to Cast Iron / Plastic / SteelDrawings1055Ductile Iron to Ductile IronDrawings1056Cast Iron / Plastic / Steel to Cast Iron / Plastic / SteelDrawings1057Concrete to Ductile IronDrawingsHTRCCorrugated polyethylene to corrugated, plastic or cast iron · high torque, 10"–60"Drawings
Size finder
Choose the material and size of the pipe on each side. The finder returns every Strong Back RC coupling — 1000 and 5000 Series — plus the universal HULK where it fits, whose ends accept both of your pipes, each flagged. Plastic and steel use Schedule 40 (IPS) outside diameters.
Side A
to
Side B
XL RC
Need more holding power? Ask for XL.
Strong Back XL RC couplings are available 12" and below. They fit the same pipe outside diameters as the matching 1000 RC size, but the extra length and additional clamp bands grip more pipe for greater holding power in demanding underground joints. Sizes that offer an XL version are flagged “Also in XL” in the results above.
Dimensional drawings
Every size, with dimensions.
Open the full Strong Back RC drawing library for the outside-diameter ranges, inch and millimeter dimensions, and a downloadable PDF for each size.
Literature.
Installation instructions, submittals and catalogs for Strong Back RC.
Frequently asked questions.
Selection, installation and compliance answers for Strong Back RC.
What is a Strong Back RC coupling?
A Strong Back RC coupling is a Fernco shielded flexible coupling with a stainless steel shear ring and a molded-in bushing added to the flexible body. The shear ring resists the earth loads and pipe movement found in buried service, while the flexible sleeve and stainless steel clamps make a sealed transition between two pipes of different material or outside diameter.
When should I use a Strong Back RC instead of a Standard Coupling?
Use a Strong Back RC for below-ground transitions that carry heavy earth loads or where the pipes may shift, settle or misalign. For above-ground work, a Standard Coupling handles lighter-duty joints, and a Proflex shielded coupling adds a stainless steel shield for transitions that need extra support above grade. All three seal the same way; the shielded couplings add reinforcement for their conditions.
How is the 1000 Series different from the 5000 Series?
Both are Strong Back RC shielded couplings with a stainless steel shield. The 1000 Series uses a worm-gear stainless steel band clamp and, 15 inches and smaller, is made in the USA and AIS/BABA compliant. The 5000 Series uses a 316 stainless steel nut-and-bolt clamp for larger-diameter connections and is not AIS or BABA compliant.
Which pipe materials does Strong Back RC connect?
The Strong Back RC line connects clay, cast iron, plastic, steel, concrete and ductile iron pipe, in same-material and transition joints. The series sets the material pairing, for example the 1002 Series connects clay to cast iron, plastic or steel, and the 1056 Series connects cast iron, plastic or steel to cast iron, plastic or steel.
What is the installation torque?
Tighten the clamps to 60 inch-pounds. Couplings 16 inches and larger ship with high torque bands and are tightened to 120 inch-pounds. Pressure test the joint before backfilling or concealing it. Follow the current Fernco installation instructions for the specific coupling.
What standards does Strong Back RC meet?
Strong Back RC couplings are manufactured to conform to ASTM C1173 and CSA B602 performance requirements, and the gasket meets ASTM D5926, ASTM C1173 and CSA B602. Listings by series are on the Codes and Standards page. Always confirm the application with your local plumbing code.
Are Strong Back RC couplings AIS and BABA compliant?
1000 Series Strong Back RC couplings 15 inches and smaller are made in the USA and comply with the American Iron and Steel (AIS) and Build America, Buy America (BABA) requirements, which supports federally funded underground infrastructure work. The 5000 Series is not AIS or BABA compliant. See the AIS and BABA page for the letter and the compliant product list.
How do I find the right coupling for my two pipes?
Use the size finder on this page: choose the material and size of the pipe on each side of the joint. Fernco couplings seal by outside diameter, so the finder returns every Strong Back RC coupling whose ends accept both of your pipe outside diameters, then links you to the drawing and dimensions for each match. If you are unsure of a pipe outside diameter, measure it and compare it to the ranges shown.