RMS Commercial Building Mitigation 2 — Questions and Answers
Question 1: In a large commercial building with multiple sub-slabs, what is the primary reason for installing multiple suction points?
- To reduce electrical costs
- To ensure adequate pressure field extension across all zones (Correct answer)
- To comply with fire code requirements
- To simplify system maintenance
Correct answer: To ensure adequate pressure field extension across all zones
Multiple suction points are required when a single point cannot extend the negative pressure field across the entire sub-slab area.
Question 2: Which document is required before beginning radon mitigation work in a commercial building in most U.S. jurisdictions?
- EPA Form 550-F-09-002
- A building permit (Correct answer)
- An OSHA safety plan
- A radon testing certificate
Correct answer: A building permit
Most jurisdictions require a building permit before structural modifications such as core drilling and pipe installation in commercial buildings.
Question 3: A school building has radon levels of 6.2 pCi/L in occupied classrooms. According to EPA guidance, what action is recommended?
- Re-test in 90 days before deciding
- Mitigate the building as soon as possible (Correct answer)
- Increase ventilation only and retest in one year
- Post radon warnings and continue monitoring
Correct answer: Mitigate the building as soon as possible
EPA recommends mitigation when school radon levels exceed 4 pCi/L in frequently occupied areas.
Question 4: What type of fan is most appropriate for a large commercial Sub-Slab Depressurization (SSD) system requiring high airflow at moderate static pressure?
- Centrifugal blower fan (Correct answer)
- Axial inline fan
- Squirrel cage fan
- Variable speed DC fan
Correct answer: Centrifugal blower fan
Centrifugal blower fans are preferred for large commercial SSD systems because they deliver high airflow at the moderate static pressures typical in those applications.
Question 5: When installing radon mitigation piping through a fire-rated wall in a commercial building, what is required?
- No special measures are needed if pipe diameter is under 4 inches
- Fire-rated sleeve or intumescent collar must be installed (Correct answer)
- Pipe must be metal within the wall cavity only
- A shutoff valve must be installed on each side of the wall
Correct answer: Fire-rated sleeve or intumescent collar must be installed
Building codes require fire-rated sleeves or intumescent collars when penetrating fire-rated assemblies to maintain the fire separation rating.
Question 6: In a commercial building, which foundation type presents the greatest challenge for achieving uniform sub-slab depressurization?
- Monolithic slab on grade
- Slab with gravel sub-base
- Slab with multiple isolated footings and interior walls (Correct answer)
- Slab with post-tension cables
Correct answer: Slab with multiple isolated footings and interior walls
Multiple isolated footings and interior walls create compartments that restrict pressure field extension, requiring additional suction points.
Question 7: A diagnostic pressure field extension test in a commercial building shows less than -1 Pa at 10 feet from the suction point. What does this indicate?
- The system is performing adequately
- Sub-slab communication is poor and additional suction points are needed (Correct answer)
- The fan is oversized for the application
- The building envelope is too tight
Correct answer: Sub-slab communication is poor and additional suction points are needed
A pressure differential of less than -1 Pa at 10 feet indicates inadequate sub-slab communication, requiring additional suction points for effective mitigation.
RMS Commercial Building Mitigation 2
In a large commercial building with multiple sub-slabs, what is the primary reason for installing multiple suction points?