IICRC APPLIED STRUCTURAL DRYING VERIFIED
QUESTIONS AND ANSWERS 2025 LATEST SOLUTIONS
Air Filtration Device (ADF) - ANSWER-Commonly called an air scrubber or negative air
machine if airborne particles need to be reduced, you could use an appropriately
installed _______ ________ ________
Air Filtration Device - ANSWER-AFD
Assembly Construction - ANSWER-Prior to determining the best drying system for
affected materials, restorers should identify and understand the assembly construction
(ie wall assembly, floor assembly)
Category 1 - ANSWER-water originates from a sanitary source and does not pose
substantial risk for dermal, ingestion, inhalation, or exposure. Uncontaminated and
routinely cleaned
Category 2 - ANSWER-water contains significant contamination and has the potential to
cause discomfort or sickness if contacted or consumed by humans
Category 3 - ANSWER-water is grossly contaminated and can contain pathogenic,
toxigenic, or other harmful agents
Sewage Back Up - ANSWER-Category 3
Clean water supply line - ANSWER-Category 1
Class 1 - ANSWER-Least amount of water absorption and evaporation load - Wet
porous materials - water loss is less then 5% of the area
Class 2 - ANSWER-Significant amount of water absorption and evaporation load - water
intrusion where wet represents 5% - 40% of the area.
Class 3 - ANSWER-greatest amount of water absorption and evaporation load. Water
intrusion where wet represents over 40% of the area
Class 4 - ANSWER-deeply held or bound water. Significant amount of water absorption
into low evaporation materials. Drying may require special drying methods, longer
drying time, or substantial water vapor pressure differentials.
Closed drying system - ANSWER-Uses mechanical dehumidification and is not open to
outside air. Used if there are security issues, the outside air is not conductive to drying
or when access to outside air is not possible.
, Conventual refrigerant dehumidifier - ANSWER-Removes water vapor from the air by
lowering the temperature of the incoming air to below dew point and causing the water
to condense on the coils. Cold and hot surfaces created with gases inside a closed coil
system.
Combination Drying System - ANSWER-uses some outdoor air with dehumidifiers to
accelerate the drying process. This can include periodically venting (flushing) the
structure, using negative pressure or using small openings to the outside
Desiccant dehumidifier - ANSWER-Removes water vapor from the air through
absorption. Usually requires more amperage as compared to refrigerant dehumidifier.
Desiccants create the lowest vapor pressure which work best on low porosity materials.
When a desiccant dehu is drawing outside air and ducting processed air inside a
building it can create positive pressure in the building. To improve desiccant dehu
performance, it may be beneficial to pre-cool the desiccants air intake
Infiltration - ANSWER-High humidity outside air could affect the drying climate adversely
due to ______________
1. Tightness of the building envelope
2. Prevailing weather
3. HVAC
4. Class of Water
5. Building Construction
5. Build out density - ANSWER-Favors that affect the detailed dehumidifier calculation
is:
Detailed Dehumidification Calculation - ANSWER-See Chart:
Cubic Feet : Divided by 70 = Base Pints per day
Multiply the 5 multipliers together: Build out density x building construction x class of
water x HVAC x Weather Impact = Multiplier
Multiply Base Pints per day x Multiplier = Adjusted Pints Per Day
Dry Standards - ANSWER-The unaffected material readings are called ______ ______.
You know you can use this as your drying goal. Your drying goal is this plus 10% of it.
Drying Goal Calculation - ANSWER-Dry standard + (Dry standard x 10%) =
____________________
Why does demolition occur - ANSWER-1. Removing Materials to eliminate safety
hazards
2. Removing materials that have suffered primary damage and are not restorable
3. Removing porous materials that are holding odor
5. Removing vapor barriers to assist with drying efforts
6. Removing materials to reduce drying time
7. Removing materials to open cavities or areas to provide additional needed services
QUESTIONS AND ANSWERS 2025 LATEST SOLUTIONS
Air Filtration Device (ADF) - ANSWER-Commonly called an air scrubber or negative air
machine if airborne particles need to be reduced, you could use an appropriately
installed _______ ________ ________
Air Filtration Device - ANSWER-AFD
Assembly Construction - ANSWER-Prior to determining the best drying system for
affected materials, restorers should identify and understand the assembly construction
(ie wall assembly, floor assembly)
Category 1 - ANSWER-water originates from a sanitary source and does not pose
substantial risk for dermal, ingestion, inhalation, or exposure. Uncontaminated and
routinely cleaned
Category 2 - ANSWER-water contains significant contamination and has the potential to
cause discomfort or sickness if contacted or consumed by humans
Category 3 - ANSWER-water is grossly contaminated and can contain pathogenic,
toxigenic, or other harmful agents
Sewage Back Up - ANSWER-Category 3
Clean water supply line - ANSWER-Category 1
Class 1 - ANSWER-Least amount of water absorption and evaporation load - Wet
porous materials - water loss is less then 5% of the area
Class 2 - ANSWER-Significant amount of water absorption and evaporation load - water
intrusion where wet represents 5% - 40% of the area.
Class 3 - ANSWER-greatest amount of water absorption and evaporation load. Water
intrusion where wet represents over 40% of the area
Class 4 - ANSWER-deeply held or bound water. Significant amount of water absorption
into low evaporation materials. Drying may require special drying methods, longer
drying time, or substantial water vapor pressure differentials.
Closed drying system - ANSWER-Uses mechanical dehumidification and is not open to
outside air. Used if there are security issues, the outside air is not conductive to drying
or when access to outside air is not possible.
, Conventual refrigerant dehumidifier - ANSWER-Removes water vapor from the air by
lowering the temperature of the incoming air to below dew point and causing the water
to condense on the coils. Cold and hot surfaces created with gases inside a closed coil
system.
Combination Drying System - ANSWER-uses some outdoor air with dehumidifiers to
accelerate the drying process. This can include periodically venting (flushing) the
structure, using negative pressure or using small openings to the outside
Desiccant dehumidifier - ANSWER-Removes water vapor from the air through
absorption. Usually requires more amperage as compared to refrigerant dehumidifier.
Desiccants create the lowest vapor pressure which work best on low porosity materials.
When a desiccant dehu is drawing outside air and ducting processed air inside a
building it can create positive pressure in the building. To improve desiccant dehu
performance, it may be beneficial to pre-cool the desiccants air intake
Infiltration - ANSWER-High humidity outside air could affect the drying climate adversely
due to ______________
1. Tightness of the building envelope
2. Prevailing weather
3. HVAC
4. Class of Water
5. Building Construction
5. Build out density - ANSWER-Favors that affect the detailed dehumidifier calculation
is:
Detailed Dehumidification Calculation - ANSWER-See Chart:
Cubic Feet : Divided by 70 = Base Pints per day
Multiply the 5 multipliers together: Build out density x building construction x class of
water x HVAC x Weather Impact = Multiplier
Multiply Base Pints per day x Multiplier = Adjusted Pints Per Day
Dry Standards - ANSWER-The unaffected material readings are called ______ ______.
You know you can use this as your drying goal. Your drying goal is this plus 10% of it.
Drying Goal Calculation - ANSWER-Dry standard + (Dry standard x 10%) =
____________________
Why does demolition occur - ANSWER-1. Removing Materials to eliminate safety
hazards
2. Removing materials that have suffered primary damage and are not restorable
3. Removing porous materials that are holding odor
5. Removing vapor barriers to assist with drying efforts
6. Removing materials to reduce drying time
7. Removing materials to open cavities or areas to provide additional needed services
