Conceptual Study Guide: IICRC MRS Exam
Principles (Based on ANSI/IICRC S520 Standard)
IICRC MRS Exam Preparation: V2 Essential
Concepts & Rationales
Q1: What is the primary goal of mold remediation according to the
S520?
A: To return affected materials to a "normal fungal ecology" for that
specific environment. It is not sterilization. The focus is
removing amplification (active growth) and correcting the moisture
source.
Q2: A remediation plan calls for removing moldy drywall and
insulation. What containment level is typically required?
A: Critical Containment (full poly sheeting sealed on all sides with
negative air pressure). This is standard for Condition 3 removal of
porous materials, as it isolates the work area and prevents cross-
contamination.
Q3: What is the MINIMUM respiratory protection for a worker
performing remediation inside a Condition 3 containment area?
A: A tight-fitting, full-facepiece respirator with P100 (HEPA)
cartridges. Half-face respirators are not sufficient for Condition 3 work.
The full facepiece also provides eye protection.
Q4: During post-remediation verification (PRV), what is the first
and most important criterion that must be met?
A: The area must be visually clean. No dust, debris, or visible
contamination. If it fails the visual inspection, further testing (air/surface
samples) is not yet appropriate. "Visually clean" is the mandatory first
pass.
,Q5: What must be confirmed BEFORE any remediation work
begins?
A: The source of moisture has been identified and
corrected. Remediating mold while water intrusion continues is futile
and violates the core principle of the S520.
Q6: What is the standard procedure for porous materials (like
drywall, carpet padding, or ceiling tiles) with mold growth?
A: Remove and discard. Porous materials cannot be reliably cleaned to
a "normal fungal ecology" standard because hyphae (roots) penetrate
deep into the material matrix.
Q7: What is the purpose of creating negative air pressure inside a
containment area?
A: To ensure that air flows FROM the clean areas INTO the
contained work area, preventing contaminated air from escaping into
occupied spaces. This is achieved with HEPA-filtered air scrubbers set
to exhaust out of the containment.
Q8: When should HEPA vacuuming be performed on a remediated
surface?
A: It is a multi-step process: 1) Pre-cleaning (after source
removal), 2) After wet-cleaning or scrubbing to remove residues,
and 3) As part of the final cleaning of surfaces outside the containment
during cleanup.
Q9: Who should ideally perform the final Post-Remediation
Verification and "clear" a project?
A: A qualified third-party IEQ (Indoor Environmental Quality)
professional who is independent of the remediation contractor. This
avoids a conflict of interest.
Q10: What defines "Condition 2" in an indoor environment?
A: The presence of settled spores, hyphal fragments, or other fungal
structures that have been transported from a Condition 3 area. There is
,no amplification (growth) in the Condition 2 area itself, but it requires
cleaning.
Q11: What is the correct waste handling procedure for mold-
contaminated porous materials?
A: Seal in 6-mil polyethylene bags inside the containment area. Wipe
or spray the bag exteriors with a cleaning agent, then transport the sealed
bags directly out of the building for disposal following local regulations.
Q12: What is the primary role of a cleaning agent (e.g., detergent,
EPA-registered antimicrobial) in mold remediation?
A: To act as a surfactant to suspend soils and fungal residues so they
can be physically removed by wiping, scrubbing, or rinsing. The
physical removal is more critical than any "killing" effect.
Q13: When is an antimicrobial coating (sealant) appropriately
used?
A: Only after cleaning and verification, on semi-porous
materials (like wood framing) to encapsulate any microscopic residues.
It is never a substitute for proper source removal and cleaning.
Q14: What engineering control is mandatory for all projects
involving the disturbance of moldy materials?
A: Containment of the work area. The level (limited, full, critical)
depends on the size and condition, but some form of containment to
limit spore spread is always required.
Q15: What document must a remediator provide that details the
scope of work, methods, and PPE to be used?
A: A Work Plan or Remediation Protocol. This is a required
document that guides the project and communicates procedures to all
stakeholders.
Q16: Why is drying considered a critical final step in mold
remediation?
A: To prevent secondary water damage and renewed microbial
, growth on the remaining or new materials. Remediation is not complete
until moisture levels are returned to normal (per S500 principles).
Q17: What is a key difference between the IICRC S520 (Mold
Remediation) and S500 (Water Damage Restoration) standards?
A: The S500 focuses on rapid water removal and
drying to prevent microbial growth. The S520 provides procedures for
assessment and removal after growth has occurred. They are
complementary.
Q18: What should be done with a mold-contaminated HVAC
system?
A: Shut it down immediately. Remediation requires specialized
procedures, often involving containment of the plenums and ducts,
HEPA vacuuming, and cleaning or replacement of contaminated
components (like insulation). It is a complex task.
Q19: According to the S520, what is the basis for all remediation
decisions and methods?
A: Professional judgment based on the principles and definitions in
the standard, applied to the specific conditions of the project. It is not a
rigid, step-by-step cookbook, but a framework for decision-making.
Q20: What is the ultimate measure of a successful remediation
project?
A: The affected area is returned to a Condition 1 state (normal fungal
ecology for that space), is visually clean, dry, and fit for its intended
use—as verified by a qualified professional.
Q21: What is the primary purpose of a preliminary assessment?
A: To establish a baseline condition (defining the microbial ecology as
Condition 1, 2, or 3), identify the moisture source, and determine the
scope of the remediation. This informs the Work Plan.
Q22: A remediation project involves less than 10 contiguous square
feet of mold growth on non-porous sheathing in an attic. What level
of containment is likely adequate?
Principles (Based on ANSI/IICRC S520 Standard)
IICRC MRS Exam Preparation: V2 Essential
Concepts & Rationales
Q1: What is the primary goal of mold remediation according to the
S520?
A: To return affected materials to a "normal fungal ecology" for that
specific environment. It is not sterilization. The focus is
removing amplification (active growth) and correcting the moisture
source.
Q2: A remediation plan calls for removing moldy drywall and
insulation. What containment level is typically required?
A: Critical Containment (full poly sheeting sealed on all sides with
negative air pressure). This is standard for Condition 3 removal of
porous materials, as it isolates the work area and prevents cross-
contamination.
Q3: What is the MINIMUM respiratory protection for a worker
performing remediation inside a Condition 3 containment area?
A: A tight-fitting, full-facepiece respirator with P100 (HEPA)
cartridges. Half-face respirators are not sufficient for Condition 3 work.
The full facepiece also provides eye protection.
Q4: During post-remediation verification (PRV), what is the first
and most important criterion that must be met?
A: The area must be visually clean. No dust, debris, or visible
contamination. If it fails the visual inspection, further testing (air/surface
samples) is not yet appropriate. "Visually clean" is the mandatory first
pass.
,Q5: What must be confirmed BEFORE any remediation work
begins?
A: The source of moisture has been identified and
corrected. Remediating mold while water intrusion continues is futile
and violates the core principle of the S520.
Q6: What is the standard procedure for porous materials (like
drywall, carpet padding, or ceiling tiles) with mold growth?
A: Remove and discard. Porous materials cannot be reliably cleaned to
a "normal fungal ecology" standard because hyphae (roots) penetrate
deep into the material matrix.
Q7: What is the purpose of creating negative air pressure inside a
containment area?
A: To ensure that air flows FROM the clean areas INTO the
contained work area, preventing contaminated air from escaping into
occupied spaces. This is achieved with HEPA-filtered air scrubbers set
to exhaust out of the containment.
Q8: When should HEPA vacuuming be performed on a remediated
surface?
A: It is a multi-step process: 1) Pre-cleaning (after source
removal), 2) After wet-cleaning or scrubbing to remove residues,
and 3) As part of the final cleaning of surfaces outside the containment
during cleanup.
Q9: Who should ideally perform the final Post-Remediation
Verification and "clear" a project?
A: A qualified third-party IEQ (Indoor Environmental Quality)
professional who is independent of the remediation contractor. This
avoids a conflict of interest.
Q10: What defines "Condition 2" in an indoor environment?
A: The presence of settled spores, hyphal fragments, or other fungal
structures that have been transported from a Condition 3 area. There is
,no amplification (growth) in the Condition 2 area itself, but it requires
cleaning.
Q11: What is the correct waste handling procedure for mold-
contaminated porous materials?
A: Seal in 6-mil polyethylene bags inside the containment area. Wipe
or spray the bag exteriors with a cleaning agent, then transport the sealed
bags directly out of the building for disposal following local regulations.
Q12: What is the primary role of a cleaning agent (e.g., detergent,
EPA-registered antimicrobial) in mold remediation?
A: To act as a surfactant to suspend soils and fungal residues so they
can be physically removed by wiping, scrubbing, or rinsing. The
physical removal is more critical than any "killing" effect.
Q13: When is an antimicrobial coating (sealant) appropriately
used?
A: Only after cleaning and verification, on semi-porous
materials (like wood framing) to encapsulate any microscopic residues.
It is never a substitute for proper source removal and cleaning.
Q14: What engineering control is mandatory for all projects
involving the disturbance of moldy materials?
A: Containment of the work area. The level (limited, full, critical)
depends on the size and condition, but some form of containment to
limit spore spread is always required.
Q15: What document must a remediator provide that details the
scope of work, methods, and PPE to be used?
A: A Work Plan or Remediation Protocol. This is a required
document that guides the project and communicates procedures to all
stakeholders.
Q16: Why is drying considered a critical final step in mold
remediation?
A: To prevent secondary water damage and renewed microbial
, growth on the remaining or new materials. Remediation is not complete
until moisture levels are returned to normal (per S500 principles).
Q17: What is a key difference between the IICRC S520 (Mold
Remediation) and S500 (Water Damage Restoration) standards?
A: The S500 focuses on rapid water removal and
drying to prevent microbial growth. The S520 provides procedures for
assessment and removal after growth has occurred. They are
complementary.
Q18: What should be done with a mold-contaminated HVAC
system?
A: Shut it down immediately. Remediation requires specialized
procedures, often involving containment of the plenums and ducts,
HEPA vacuuming, and cleaning or replacement of contaminated
components (like insulation). It is a complex task.
Q19: According to the S520, what is the basis for all remediation
decisions and methods?
A: Professional judgment based on the principles and definitions in
the standard, applied to the specific conditions of the project. It is not a
rigid, step-by-step cookbook, but a framework for decision-making.
Q20: What is the ultimate measure of a successful remediation
project?
A: The affected area is returned to a Condition 1 state (normal fungal
ecology for that space), is visually clean, dry, and fit for its intended
use—as verified by a qualified professional.
Q21: What is the primary purpose of a preliminary assessment?
A: To establish a baseline condition (defining the microbial ecology as
Condition 1, 2, or 3), identify the moisture source, and determine the
scope of the remediation. This informs the Work Plan.
Q22: A remediation project involves less than 10 contiguous square
feet of mold growth on non-porous sheathing in an attic. What level
of containment is likely adequate?
