Spruce Flexible Coupling – 6" × 4" (White)

Spruce Flexible Coupling – 6" × 4" White

Flexible PVC reducing coupling for connecting a 6" radon fan to 4" Schedule 40 PVC pipe.

The Spruce 6" × 4" white flexible coupling provides a secure, airtight reducing connection between a 6"-inlet radon fan and a 4" Schedule 40 PVC vent stack. Built with high-performance flexible PVC and stainless steel clamps, it absorbs fan vibration, accommodates minor misalignment, and creates a reliable seal — making it the standard transition fitting for professional radon mitigators stepping a high-capacity fan down to a 4" riser.

Application

Used to join a 6" radon fan outlet or inlet to 4" PVC pipe in sub-slab depressurization systems. Commonly installed at the fan-to-stack transition for higher-capacity fans — such as the RadonAway RP265, GP501, and XP/XR series — that use a 6" collar feeding a 4" vent run. The flexible body decouples fan vibration from the pipe and simplifies alignment between the fan and stack.

Features

• High-performance flexible PVC construction
• Stainless steel clamps included for a secure, airtight seal
• Reduces 6" to 4" — the standard high-capacity fan-to-stack transition
• White finish blends with Schedule 40 PVC pipe
• Absorbs vibration from inline radon fans
• Accommodates minor pipe misalignment
• UV resistant; conforms to ASTM C1173 and CSA B602
• Operating temperature range 30°F to 140°F (-1°C to 60°C)

Specifications

FAQ

What is a 6" × 4" flexible coupling used for in radon mitigation?
It connects a 6"-inlet radon fan to a 4" Schedule 40 PVC vent stack, creating an airtight, vibration-absorbing transition between the fan and the pipe.

Which radon fans use a 6" × 4" coupling?
Higher-capacity RadonAway fans with a 6" collar — including the RP265, GP501, and XP/XR series — commonly step down to a 4" riser using this coupling.

Does it come with clamps?
Yes. Stainless steel clamps are included for a corrosion-resistant, airtight seal.

Can I use this outdoors?
The coupling is UV resistant; however, in Canada radon fans and their fittings are installed indoors (attic, basement, or garage). Outdoor fan installation is not permitted under Canadian guidelines.

Will it fit Schedule 40 PVC?
Yes. The 4" end is sized for standard 4" Schedule 40 PVC pipe.

Is the coupling load-bearing?
No. The pipe should be independently supported; the flexible coupling is a sealing and vibration-isolation joint, not a structural support.

What standards does it meet?
It conforms to ASTM C1173 and CSA B602.

Why use a flexible coupling instead of a rigid reducer?
A flexible coupling absorbs fan vibration, tolerates minor misalignment between the fan and stack, and can be loosened for service — advantages a glued rigid reducer does not offer.