InspectUSA.com Flexible Coupling Sizing Chart

There has been some confusion in coupling size over the years. In the radon fan, and radon mitigation industry, we use flexible couplings to create a service break between the radon fan and the vent pipe. The vent pipe normally consists of schedule 20 or 40 PVC pipe and the flexible couplings allow the installer to adapt to various size vent pipes and fans. The fans typically have 3.5", 4.5", 6", and 8" O.D. intake and exhaust openings. The PVC pipe will range between 2.5" and 6.5" O.D.

Flexible couplings are not made specifically for the radon fan industry. These are "repair" couplings widely used in the plumbing and sewage trades to adapt to different types and sizes of piping. When using the flex couplings with our 6" and 8" fans, you may find that the Model names do not match up precisely with the manufacturer's coupling name. Some connections may be a bit snug, but they do fit and they are all that is available for making these connections.

Please use the chart below to help better understand the names, sizing, and use of flexible couplings with RadonAway Fans.

Coupling
Inside Dia.

Manufacturer's Model Name

PVC Pipe Size

RadonAway Product Connection
2 x 2

2.45" x 2.45"

2" Plastic or Cast Iron to 2" Plastic or Cast Iron

2"

2" Fan: Discharge of HS Series Fan
2 x 3

2.45" x 3.45"

2" Plastic or Cast Iron to 3" Plastic or Cast Iron

2"

AIRaider Discharge Connection
3 x 3

3.45" x 3.45"

3" Plastic or Cast Iron to 3" Plastic or Cast Iron

3"

3" Fans: GPc Series Fans, Intake of HS Series Fans
4 x 3

3.45" x 4.45"

3" Plastic or Cast Iron to 4" Plastic or Cast Iron

3"
4"

4" Fans: RP140, RP145, XP Series
3" Fans: GX Series, GPc Series
6 x 3

3.45" x 5.35"

3" Plastic or Cast Iron to 4" Clay

3"

6" Fans: XR261, RP260, RP265
4 x 4

4.45" x 4.45"

4" Plastic or Cast Iron to 4" Plastic or Cast Iron

4"

4" Fans: RP140, RP145, SF180, XP Series
6 x 4

4.45" x 5.75"

4" Plastic or Cast Iron to 4" Concrete

4"

6" Fans: XR261, RP260, RP265
6 x 6

6.38" x 5.54"

4" Clay to 6" Plastic or Cast Iron

4"

6" Fans: XR261, RP260, RP265
8 x 4

4.39" x 8.52"

Cast Iron and Plastic to Cast Iron, Plastic

4"

8" Fan: RP380
8 x 6

7.78" x 6.38"

6" Plastic or Cast Iron to 6" Concrete

6"

8" Fan: RP380

FLEX COUPLING SIZING CHART