System Design & Installation Flashcards

What is the most common type of active radon mitigation system installed in U.S. homes?

Answer: Active sub-slab depressurization (ASD)

Active sub-slab depressurization is the most common and effective residential radon mitigation method, using a fan to draw radon from beneath the slab and vent it above the roofline.

Where should the radon vent pipe exhaust be located?

Answer: Above the roofline, at least 10 feet from windows and openings

The radon exhaust must terminate above the roof and at least 10 feet from any operable opening to prevent re-entry of radon into the building.

What type of fan is typically used in residential radon mitigation systems?

Answer: Inline centrifugal fan rated for continuous operation

Residential radon systems use inline centrifugal fans specifically designed for continuous 24/7 operation, installed in the vent pipe above the living space or in the attic.

What is a diagnostic pressure field extension test?

Answer: A test measuring how far suction extends under the slab from the mitigation point

Pressure field extension testing measures suction at various points under the slab to verify that a single suction point adequately depressurizes the entire sub-slab area.

What sealant is typically used to seal pipe penetrations in radon systems?

Answer: Polyurethane caulk or fire-rated sealant rated for the application

Polyurethane caulk or appropriate fire-rated sealants are used to seal pipe penetrations, cracks, and joints to prevent radon from bypassing the mitigation system through unsealed openings.

What is radon-resistant new construction (RRNC)?

Answer: Building techniques incorporated during new construction to prevent radon entry

RRNC includes features like gravel sub-slab layers, vapor barriers, sealed penetrations, and passive vent pipes installed during construction, making future mitigation easier if needed.