MRS Mold Remediation Techniques and Procedures 4 — Questions and Answers
Question 1: What is the correct air exchange rate recommendation for a negative air machine in a remediation containment zone?
- 1-2 air changes per hour
- 4-6 air changes per hour (Correct answer)
- 15-20 air changes per hour
- 30-40 air changes per hour
Correct answer: 4-6 air changes per hour
Negative air machines should provide 4-6 air changes per hour within the containment zone to maintain effective negative pressure and air quality.
Question 2: When using dry ice blasting for mold remediation on structural lumber, what is a key advantage over conventional methods?
- It kills mold spores with sub-zero temperatures on contact and leaves no secondary waste (Correct answer)
- It is the least expensive method and requires no PPE
- It adds moisture to wood which prevents regrowth
- It permanently seals wood pores preventing future mold growth
Correct answer: It kills mold spores with sub-zero temperatures on contact and leaves no secondary waste
Dry ice blasting removes mold from structural wood without adding moisture and the dry ice sublimates, leaving no secondary waste to clean up.
Question 3: A remediator discovers mold behind a wall cavity during initial demolition that is significantly larger than initially assessed. What is the correct course of action?
- Continue remediation since the work has already started
- Stop work, expand containment, reassess scope, and notify the client before proceeding (Correct answer)
- Quickly remove the additional material before the client notices to avoid delays
- Apply biocide spray and re-close the wall without further demolition
Correct answer: Stop work, expand containment, reassess scope, and notify the client before proceeding
Work must stop when scope significantly changes; containment must be expanded, the new scope assessed, and the client notified before continuing.
Question 4: Which type of air sampling method collects mold spores on a culture medium to identify viable (living) mold?
- Spore trap sampling (non-viable)
- Bulk sampling with tape lift
- Impaction sampling onto an agar plate (viable culture) (Correct answer)
- Swab sampling analyzed by direct microscopy
Correct answer: Impaction sampling onto an agar plate (viable culture)
Viable culture sampling using impaction onto agar plates collects living mold spores that can be cultured and identified, unlike spore trap methods that capture all spores.
Question 5: What is the recommended approach for remediating mold on concrete block walls in a basement?
- Paint over the mold with standard latex paint to seal it
- Wire brush, HEPA vacuum, apply biocide, allow to dry, then encapsulate if needed (Correct answer)
- Pressure wash with plain water and allow to air dry
- Apply joint compound over affected areas to cover the mold
Correct answer: Wire brush, HEPA vacuum, apply biocide, allow to dry, then encapsulate if needed
Concrete block requires mechanical scrubbing with a wire brush, HEPA vacuuming, biocide application, thorough drying, and encapsulation for severely affected areas.
Question 6: What does the term 'condition 1' describe in the IICRC S520 standard for mold remediation?
- Surfaces with visible mold growth requiring immediate demolition
- Normal fungal ecology where no contamination is present (Correct answer)
- Settled dust with elevated mold spore counts but no visible growth
- Active water intrusion causing ongoing mold proliferation
Correct answer: Normal fungal ecology where no contamination is present
Condition 1 in the IICRC S520 standard describes a normal fungal ecology where mold spore types and counts are typical of an unaffected indoor environment.
Question 7: During mold remediation of a commercial kitchen, which additional hazard must the remediator consider that differs from typical residential jobs?
- Higher mold spore concentrations due to cooking activities
- Presence of food-borne pathogens combined with mold in grease-laden environments (Correct answer)
- Requirement for all workers to have food handler certifications
- Mandatory use of ozone generators to sterilize kitchen equipment
Correct answer: Presence of food-borne pathogens combined with mold in grease-laden environments
Commercial kitchens present a combined hazard of mold and food-borne pathogens growing in grease-laden surfaces, requiring additional decontamination protocols.
MRS Mold Remediation Techniques and Procedures 4
What is the correct air exchange rate recommendation for a negative air machine in a remediation containment zone?