MRS Removal Techniques & Methods 2 — Questions and Answers
Question 1: Which removal technique is recommended when mold is found on concrete block walls in a basement?
- Wire brushing followed by HEPA vacuuming (Correct answer)
- Painting over the surface with mold-resistant paint
- Applying bleach and leaving without rinsing
- Sanding with an orbital sander without containment
Correct answer: Wire brushing followed by HEPA vacuuming
Wire brushing dislodges mold from porous concrete, and HEPA vacuuming captures spores without spreading contamination.
Question 2: During dry ice blasting for mold removal, what is the PRIMARY safety concern unique to this method?
- Carbon dioxide buildup in enclosed spaces (Correct answer)
- Excessive heat generation at the blast site
- Static electricity igniting mold spores
- Water intrusion from the dry ice melting
Correct answer: Carbon dioxide buildup in enclosed spaces
Dry ice (CO2) sublimates and can displace oxygen in poorly ventilated spaces, creating an asphyxiation hazard.
Question 3: What is the purpose of applying an encapsulant after mold removal on a wood structural member?
- To seal any residual spores that cannot be physically removed (Correct answer)
- To add structural strength to the wood
- To eliminate the need for post-remediation verification testing
- To replace the antimicrobial treatment step
Correct answer: To seal any residual spores that cannot be physically removed
Encapsulants seal pores in wood to prevent residual spores from becoming airborne in the future.
Question 4: When remediating mold on fiberglass insulation batts, the BEST practice is to:
- Remove and discard the insulation entirely (Correct answer)
- HEPA vacuum the surface and reinstall
- Spray with biocide and leave in place
- Apply encapsulant to the insulation facing
Correct answer: Remove and discard the insulation entirely
Fiberglass insulation cannot be adequately cleaned and must be bagged and discarded to prevent continued contamination.
Question 5: Which of the following BEST describes the 'soda blasting' mold removal method?
- Using sodium bicarbonate propelled by compressed air to abrade mold from surfaces (Correct answer)
- Applying a sodium hypochlorite solution under high pressure
- Mixing baking soda with water and scrubbing manually
- Injecting carbonated water into wall cavities to kill mold
Correct answer: Using sodium bicarbonate propelled by compressed air to abrade mold from surfaces
Soda blasting propels sodium bicarbonate particles at high velocity to remove mold without damaging softer substrates.
Question 6: What is a key advantage of using negative air pressure during mold removal compared to positive pressure?
- It prevents contaminated air from escaping the work area into clean zones (Correct answer)
- It speeds up the drying of wet materials
- It reduces the cost of PPE required for workers
- It eliminates the need for physical containment barriers
Correct answer: It prevents contaminated air from escaping the work area into clean zones
Negative air pressure draws air inward through HEPA filtration, preventing spore migration to unaffected areas.
Question 7: According to IICRC S520, Category 3 (heavily contaminated) areas typically require removal of porous materials to a distance of how far beyond the visible mold boundary?
- 12 inches beyond the visible growth (Correct answer)
- 2 inches beyond the visible growth
- Until moisture readings normalize
- Only visibly affected material need be removed
Correct answer: 12 inches beyond the visible growth
IICRC S520 recommends removing porous materials 12 inches beyond visible mold to capture unseen hyphae growth.
MRS Removal Techniques & Methods 2
Which removal technique is recommended when mold is found on concrete block walls in a basement?