Mitigation System Design & Installation Flashcards

What is the primary purpose of a radon mitigation system?

Answer: To reduce the radon levels inside the building

The sole and primary purpose of a radon mitigation system is to lower the concentration of radon gas within a building to levels considered safe by health organizations. Radon is a known carcinogen, and these systems are specifically designed to protect occupants from its harmful effects by preventing its entry or actively removing it.

Which radon mitigation system is most commonly used in homes?

Answer: Active soil depressurization system

Active soil depressurization (ASD) is the most widely used and effective method for mitigating radon in existing homes, particularly those with slab-on-grade foundations or basements. This system uses a fan to create a vacuum beneath the foundation, drawing radon from the soil and venting it safely above the roofline. Its proven effectiveness and versatility make it the industry standard.

How does an active radon mitigation system work?

Answer: It creates negative pressure to vent radon outside

An active radon mitigation system, typically an active soil depressurization system, works by using an electric fan to create a continuous negative pressure (vacuum) beneath the building's foundation. This negative pressure draws radon gas from the soil before it can enter the home and then vents it safely to the outdoors, usually above the roofline.

What is a sub-slab depressurization system?

Answer: A system that vents radon from beneath the building using pipes

A sub-slab depressurization system is a specific type of active radon mitigation system. It involves installing a suction pipe through the concrete slab floor into the gravel or soil beneath. A fan connected to this pipe draws radon-laden air from under the slab and exhausts it safely outside, preventing it from entering the living space.

Why is sealing cracks and gaps in a building important for radon mitigation?

Answer: It prevents radon from entering the building

Radon is a naturally occurring radioactive gas that seeps into buildings from the soil through cracks and other openings in the foundation. Sealing these entry points creates a physical barrier, directly blocking the primary pathway for radon gas to infiltrate the indoor environment. This is a fundamental step in reducing indoor radon concentrations and protecting occupants from its health risks.

What is the function of a radon fan in a mitigation system?

Answer: To create negative pressure and vent radon outside

A radon fan is the active component of a sub-slab depressurization system, the most common and effective mitigation method. It continuously draws air and radon gas from beneath the building's foundation, creating negative pressure. This prevents radon from being drawn into the living space and instead safely vents it outdoors, away from the building's occupants.

What are the key components of a radon mitigation system?

Answer: Fan, pipes, suction point, and venting system

A typical active radon mitigation system, such as sub-slab depressurization, consists of several interconnected components. A suction point (often a hole in the slab) collects radon gas, which is then drawn through a system of pipes by an inline fan. This fan then expels the radon safely outside the building via a dedicated venting system, usually extending above the roofline.

How can a mitigation system reduce radon levels in a building?

Answer: By venting radon gas outside

Radon mitigation systems, particularly sub-slab depressurization, work by actively drawing radon gas from beneath the building's foundation. Instead of allowing it to accumulate indoors, the system captures this gas and safely expels it into the outdoor atmosphere. This process effectively reduces indoor radon concentrations to acceptable levels.

What should be done after a radon mitigation system is installed?

Answer: Test radon levels again to ensure effectiveness

After a radon mitigation system is installed, post-mitigation testing is crucial to verify its effectiveness. This follow-up testing confirms that the system is successfully reducing radon levels below the EPA action level. It ensures the investment in mitigation has achieved its intended health protection goal.