Wrt questions and answers 2024 latest update
Category 1 correct answers 1 (previously known as "clean") - originates from a sanitary water
source
Category 2 correct answers (previously known as "gray") - contaminated; potentially causes
discomfort or sickness
Category 3 correct answers (previously known as "black") - grossly contaminated; includes
toxins, pathogens
• Regulated or hazardous materials and mold correct answers (creating special situations) - IEP
recommended
Class of Water correct answers (quantity; anticipated evaporation rate; initial dehumidifier
calculations)
Class 1 correct answers - (least amount of water, absorption and evaporation) wet less than ~5%
of combined floor, wall, and ceiling surface area - minimal moisture absorption into the materials
Class 2 correct answers (large amount of water, absorption and evaporation) wet between ~5 -
~40% of combined floor, wall, and ceiling surface area - minimal moisture absorption into the
materials
Class 3 correct answers - (greatest amount of water, absorption and evaporation) wet more than
~40% of combined floor, wall, and ceiling surface area - minimal absorption into the materials
Class 4 correct answers - (deeply held or bound water) - (e.g., hardwood; lath and plaster;
concrete) - water hidden, trapped, or bound in low evaporation assemblies; requires controlled
drying techniques, low vapor pressure, specialty equipment probable
Principles of Drying correct answers Remove excess / Evaporation / Dehumidification
(ventilation) / Temperature control
Extraction tools: correct answers Light wand - perimeter of water loss; extract glue-down
carpets; follow-up extraction-stationary tool • Stationary tool (e.g., Water claw; Flash Xtractor) -
subsurface tool; extract carpet/cushion together • Self-propelled tools (e.g., Rover; Xtreme
Xtractor) -self-propelled riding tool; multi-speed; extract carpet and cushion • Vacuum squeegee
- concrete; hardwood; vinyl; laminate • Submersion pumps - Formula - (ft2 x inches deep) ÷ 12"
= ft3 water x 7.48 = water volume
Evaporation tools correct answers Airmovers - centrifugal (laminar); axial (high-amperage; low-
amperage; focus ability) o placement -5-45 degree focus; almost touching wall; always round up
to next number § Initially one airmover each affected room
, • Airmovers correct answers centrifugal (laminar); axial (high-amperage; low-amperage; focus
ability) o placement -5-45 degree focus; almost touching wall; always round up to next number §
Initially one airmover each affected room § Additionally, add one: • Every 50-70 sq. ft. wet floor
and walls up to 24 inches high • Every 100-150 sq. ft. of affected wet ceiling and walls over 24
inches high • Each wall offset greater than 18 inches o One per 14 LF of all only (if only lower
wall and limited flooring) o One per small areas under 25 sq. ft. if upper walls and ceilings not
affected o safety screens - intake and output areas; clean with compressed air; do not block
intake o electrical safety - lightweight extension cords; three-prong plugs; electrical cord safety
Structural Cavity Drying Systems (SCDS) correct answers Vented-ducted (e.g., Turbovents 18"-
48" widths; Octi-dry; Air Wolf) o injected (e.g., Injectidry; Dri-Force; Omni-dry; Direct-it In)
Floor Drying Systems correct answers vented (e.g., Air Wolf) o injected - negative air
mats/panels (e.g., Dri-Force; Injectidry) o air-blanket style
Air Filtration Devices correct answers AFDs (negative air machines - NAM; air scrubbers;
HEPA filters)
Dehumidifier Ranges correct answers Understanding where temperature, RH, and GPP ratings
are out of working ranges
AHAM rating: correct answers pints removed at 80º F / 60% RH in 24 hours
Refrigerants correct answers Most efficient operating conditions 70º - 90º F. (most energy
efficient is an LGR)
Desiccants correct answers most efficient with incoming air from coolest/driest air possible;
capable of creating greatest pressure differentials (air and vapor pressures); produces low
humidity ratio (gpp) important to dry Class 4 materials, dense materials, and complex systems.
Uses correct answers closed-drying environments; multiple layers of materials; security
limitations; high outside (and inside) humidity conditions; no ventilation ports; basement areas
Initial dehumidification recommendations correct answers (psychrometric readings dictate
requirements after first day)
Inspection equipment: correct answers Moisture sensor
Thermo-hygrometer
Moisture meters
infrared camera and thermometer; manometer; borescope; data logger
Moisture sensor correct answers senses moisture in materials over 17% MC; helps determine
perimeter of water damage; unable to determine which layer is wet or when dry
Category 1 correct answers 1 (previously known as "clean") - originates from a sanitary water
source
Category 2 correct answers (previously known as "gray") - contaminated; potentially causes
discomfort or sickness
Category 3 correct answers (previously known as "black") - grossly contaminated; includes
toxins, pathogens
• Regulated or hazardous materials and mold correct answers (creating special situations) - IEP
recommended
Class of Water correct answers (quantity; anticipated evaporation rate; initial dehumidifier
calculations)
Class 1 correct answers - (least amount of water, absorption and evaporation) wet less than ~5%
of combined floor, wall, and ceiling surface area - minimal moisture absorption into the materials
Class 2 correct answers (large amount of water, absorption and evaporation) wet between ~5 -
~40% of combined floor, wall, and ceiling surface area - minimal moisture absorption into the
materials
Class 3 correct answers - (greatest amount of water, absorption and evaporation) wet more than
~40% of combined floor, wall, and ceiling surface area - minimal absorption into the materials
Class 4 correct answers - (deeply held or bound water) - (e.g., hardwood; lath and plaster;
concrete) - water hidden, trapped, or bound in low evaporation assemblies; requires controlled
drying techniques, low vapor pressure, specialty equipment probable
Principles of Drying correct answers Remove excess / Evaporation / Dehumidification
(ventilation) / Temperature control
Extraction tools: correct answers Light wand - perimeter of water loss; extract glue-down
carpets; follow-up extraction-stationary tool • Stationary tool (e.g., Water claw; Flash Xtractor) -
subsurface tool; extract carpet/cushion together • Self-propelled tools (e.g., Rover; Xtreme
Xtractor) -self-propelled riding tool; multi-speed; extract carpet and cushion • Vacuum squeegee
- concrete; hardwood; vinyl; laminate • Submersion pumps - Formula - (ft2 x inches deep) ÷ 12"
= ft3 water x 7.48 = water volume
Evaporation tools correct answers Airmovers - centrifugal (laminar); axial (high-amperage; low-
amperage; focus ability) o placement -5-45 degree focus; almost touching wall; always round up
to next number § Initially one airmover each affected room
, • Airmovers correct answers centrifugal (laminar); axial (high-amperage; low-amperage; focus
ability) o placement -5-45 degree focus; almost touching wall; always round up to next number §
Initially one airmover each affected room § Additionally, add one: • Every 50-70 sq. ft. wet floor
and walls up to 24 inches high • Every 100-150 sq. ft. of affected wet ceiling and walls over 24
inches high • Each wall offset greater than 18 inches o One per 14 LF of all only (if only lower
wall and limited flooring) o One per small areas under 25 sq. ft. if upper walls and ceilings not
affected o safety screens - intake and output areas; clean with compressed air; do not block
intake o electrical safety - lightweight extension cords; three-prong plugs; electrical cord safety
Structural Cavity Drying Systems (SCDS) correct answers Vented-ducted (e.g., Turbovents 18"-
48" widths; Octi-dry; Air Wolf) o injected (e.g., Injectidry; Dri-Force; Omni-dry; Direct-it In)
Floor Drying Systems correct answers vented (e.g., Air Wolf) o injected - negative air
mats/panels (e.g., Dri-Force; Injectidry) o air-blanket style
Air Filtration Devices correct answers AFDs (negative air machines - NAM; air scrubbers;
HEPA filters)
Dehumidifier Ranges correct answers Understanding where temperature, RH, and GPP ratings
are out of working ranges
AHAM rating: correct answers pints removed at 80º F / 60% RH in 24 hours
Refrigerants correct answers Most efficient operating conditions 70º - 90º F. (most energy
efficient is an LGR)
Desiccants correct answers most efficient with incoming air from coolest/driest air possible;
capable of creating greatest pressure differentials (air and vapor pressures); produces low
humidity ratio (gpp) important to dry Class 4 materials, dense materials, and complex systems.
Uses correct answers closed-drying environments; multiple layers of materials; security
limitations; high outside (and inside) humidity conditions; no ventilation ports; basement areas
Initial dehumidification recommendations correct answers (psychrometric readings dictate
requirements after first day)
Inspection equipment: correct answers Moisture sensor
Thermo-hygrometer
Moisture meters
infrared camera and thermometer; manometer; borescope; data logger
Moisture sensor correct answers senses moisture in materials over 17% MC; helps determine
perimeter of water damage; unable to determine which layer is wet or when dry
