RMS Building Science & Radon Entry 3

Question 1

Which HVAC condition is most likely to increase radon entry into a home?

Accepted Answer

A central return air system that depressurizes the lower level

Answer

Central return air systems, especially those drawing air from lower floors without balanced supply, can depressurize the basement and increase the pressure differential that draws radon in from the soil.

Question 2

What percentage of indoor radon typically enters through the building foundation and sub-slab soil in most US homes?

Accepted Answer

Greater than 80%

Answer

Studies show that in the vast majority of homes, more than 80% of indoor radon enters through foundation openings and cracks from soil beneath and around the structure.

Question 3

Hollow concrete block foundation walls are especially problematic for radon because they:

Accepted Answer

Create internal voids that act as conduits for soil gas flow

Answer

The hollow cores of concrete block walls provide interconnected channels through which soil gas can travel laterally along the wall and enter at any opening, including mortar cracks.

Question 4

Radon entry through building materials (e.g., concrete, granite countertops) is classified as which type of entry mechanism?

Accepted Answer

Diffusion from the material itself

Answer

When radon emanates from radioactive decay within building materials and migrates through pore spaces into indoor air, the mechanism is diffusion driven by concentration gradients.

Question 5

Which of the following best describes the relationship between indoor-outdoor pressure differential and radon entry rate?

Accepted Answer

Greater negative indoor pressure increases radon entry rate

Answer

A greater negative indoor pressure relative to the soil creates a stronger driving force that pulls more soil gas, including radon, through foundation openings per unit time.

(RMS) Radon Mitigation Specialist Practice Test

(RMS) Radon Mitigation Specialist Practice Test

RMS Building Science & Radon Entry 3