Flexible Couplings Fernco

🛠️ The Ultimate Fernco Coupling Selection Guide

Choosing the right coupling is about measuring the Outside Diameter (OD) of your pipes, not the internal bore.

1. Measure Twice, Order Once

To find the correct Fernco coupling, you must measure the External Diameter of both pipes you are joining.

• Pipe A: Measure the OD of the existing pipe (e.g., Clay or Cast Iron).

• Pipe B: Measure the OD of the new pipe (e.g., PVC/EN1401).

2. Standard vs. Bushing

• Standard Couplings: Use these when the two pipes have a similar OD (within 5-10mm of each other).

• Bushings/Adaptors: Use these if one pipe is significantly thinner than the other to ensure a snug, leak-proof fit under the stainless steel bands.

3. Fernco Size Chart (Quick Reference)

📋 Underground Drainage Installation Checklist

Ensuring your EN1401 system meets Building Regulations.

1. Plan the Fall (Gradient):

   • Standard drainage requires a fall of roughly 1 in 40 (25mm drop for every 1m of pipe). Too steep and solids won't move; too shallow and water won't flow.

2. Trench Preparation:

   • Dig the trench wide enough to allow for 100mm of Pea Shingle or Gravel bedding all around the pipe. This protects the pipe from sharp stones and ground movement.

3. Check the Seals:

   • Ensure all EN1401 rubber rings are present and seated correctly. Use silicone lubricant or soap on the spigot end to prevent the seal from "rolling" during connection.

4. Install Non-Return Valves (NRV):

   • If you are in a flood-prone area or near a main sewer, install an NRV in the final inspection chamber to prevent backflow into the house.

5. Access Points:

   • Install an Inspection Chamber at every change of direction or where two or more pipes meet.

6. Test Before Backfilling:

   • Perform a "leak test" by bunging the pipe and filling it with water to ensure every joint is watertight before you bury it under aggregates.