RMS Building Science & Radon Entry 2

Question 1

Which foundation type typically presents the greatest challenge for radon mitigation due to the large soil contact area?

Accepted Answer

Slab-on-grade construction

Answer

Slab-on-grade foundations have extensive soil contact across the entire floor footprint, making it difficult to create a sub-slab depressurization field that covers the whole area.

Question 2

The 'stack effect' in buildings causes radon levels to be highest in which location?

Accepted Answer

Lower floors and basement

Answer

The stack effect creates negative pressure at the lower levels of a building relative to outdoor air, drawing soil gases including radon upward through foundation openings.

Question 3

What term describes the process by which radon-laden soil gas is pulled into a building due to indoor-outdoor pressure differences?

Accepted Answer

Advection

Answer

Advection is the bulk flow of soil gas driven by pressure gradients, and it is the dominant radon entry mechanism in most buildings when indoor pressure is lower than soil pressure.

Question 4

Which soil characteristic most strongly promotes radon transport toward a building foundation?

Accepted Answer

High permeability (coarse gravel or sand)

Answer

Highly permeable soils such as coarse gravel and sand allow soil gas to move freely, greatly increasing the rate of radon transport to the building foundation.

Question 5

A sump pit without a sealed lid is a significant radon entry pathway primarily because it:

Accepted Answer

Provides a direct opening to permeable gravel fill below the slab

Answer

Sump pits typically penetrate through the slab into the permeable drainage aggregate below, creating a direct, low-resistance pathway for soil gas to enter the living space.

(RMS) Radon Mitigation Specialist Practice Test

(RMS) Radon Mitigation Specialist Practice Test

RMS Building Science & Radon Entry 2