IICRC Commercial Drying Specialist (CDS) Exam
Study Guide+questions with Corrected Answers
categories of water - ANSWER range of contamination determined by restorer /// cat 1
= clean, little risk( water supply lines, falling rainwater) // cat 2 = discomfort or sickness
(overflow from washing machines, broken aquariums) // cat 3 = grossly contaminated
(sewage and water back flow)
class of water - ANSWER amount of water absorption and evaporation load // class 1 =
less than 5% // Class 2 = significant, 5-40% // class 3 = greatest, more than 40% // class
4 = deeply held or bound
dry standard - ANSWER reasonable approximation of moisture content or level of
a material PRIOR to loss
drying goals - ANSWER target moisture levels of materials set by restorer// within
10% of dry standard
never... - ANSWER assume but always verify customer's word and surrounding areas
and floor
full or partial "sign off" - ANSWER needed when returning whole or part of building
closing/final job report - ANSWER confirms the scope of work completed & drying goals
were met
,change in category - ANSWER document explaining the reasons for degradation
(time, temp, visible contamination, odors)
regulated, hazardous, materials and mold... - ANSWER follow local, state, federal laws!
cross contamination routes - ANSWER elevators, hvac duct flows, building stack
effect, foot traffic
class 4 uniqueness - ANSWER 1/2/3 = amount of water evaporating from porous
surfaces // 4 = how slowly it will migrate through thick and low evap materials(very
different strategy)
skills outside your expertise - ANSWER call an expert
critical questions to ask - ANSWER who discovered water intrusion? what has been done
to stop? what type of facility is it? Category? pre-existing damage present or suspected?
Where are critical areas or equipment that are priority? class of saturation and
evaporation? insurance for business interruption? can we help secure the job by
responding quickly to specific critical area or need? where are there hazardous or
regulated materials or mold?
checklists & forms - ANSWER easy to use, comprehensive to cover many issues, scalable
to use on all sizes of facilities
solid wood MC within 4% of dry standard using... - ANSWER wood calibrated material
non solid wood MC within 10% of - ANSWER dry standard
, modify initial dehu capacity after... - ANSWER subsequent and following days
of psychometric readings
factors to consider adjusting dehu requirement - ANSWER agreed upon deadline to
complete // power is less than adequate // occupancy of building during drying
(potential equipment shut off, frequent opening of doors, higher moisture load) //
schedule imposed by client (wanting to be open during certain hours) // required
pressure differential to achieve contaminant control
sizing desiccant dehu - ANSWER start with determining ACH - air changes per hour
detailed calc of dehu - ANSWER for advanced restorers
build out density considers... - ANSWER building's ability to circulate dry air
throughout & the amount of wall materials need to be addressed
weather impact factor considers - ANSWER outside weather and building's envelope
ability to keep outside air from coming inside
direct expansion systems - ANSWER circulates refrigerant though a cold evaporator
coil within the system that cools air stream that is delivered via insulated ducts
throughout building // indoor air is returned to be reconditioned // think roof top units
// lowest dew point is 43-45 degrees F
chilled water systems - ANSWER circulate conditioned water (cold/hot) through
the system // distributes air to individual fan/coil located in the building
ACH - ANSWER air change rate per hour // to calculate, find the volume, multiple by # of
air changes // convert to CFM by dividing by 60
Study Guide+questions with Corrected Answers
categories of water - ANSWER range of contamination determined by restorer /// cat 1
= clean, little risk( water supply lines, falling rainwater) // cat 2 = discomfort or sickness
(overflow from washing machines, broken aquariums) // cat 3 = grossly contaminated
(sewage and water back flow)
class of water - ANSWER amount of water absorption and evaporation load // class 1 =
less than 5% // Class 2 = significant, 5-40% // class 3 = greatest, more than 40% // class
4 = deeply held or bound
dry standard - ANSWER reasonable approximation of moisture content or level of
a material PRIOR to loss
drying goals - ANSWER target moisture levels of materials set by restorer// within
10% of dry standard
never... - ANSWER assume but always verify customer's word and surrounding areas
and floor
full or partial "sign off" - ANSWER needed when returning whole or part of building
closing/final job report - ANSWER confirms the scope of work completed & drying goals
were met
,change in category - ANSWER document explaining the reasons for degradation
(time, temp, visible contamination, odors)
regulated, hazardous, materials and mold... - ANSWER follow local, state, federal laws!
cross contamination routes - ANSWER elevators, hvac duct flows, building stack
effect, foot traffic
class 4 uniqueness - ANSWER 1/2/3 = amount of water evaporating from porous
surfaces // 4 = how slowly it will migrate through thick and low evap materials(very
different strategy)
skills outside your expertise - ANSWER call an expert
critical questions to ask - ANSWER who discovered water intrusion? what has been done
to stop? what type of facility is it? Category? pre-existing damage present or suspected?
Where are critical areas or equipment that are priority? class of saturation and
evaporation? insurance for business interruption? can we help secure the job by
responding quickly to specific critical area or need? where are there hazardous or
regulated materials or mold?
checklists & forms - ANSWER easy to use, comprehensive to cover many issues, scalable
to use on all sizes of facilities
solid wood MC within 4% of dry standard using... - ANSWER wood calibrated material
non solid wood MC within 10% of - ANSWER dry standard
, modify initial dehu capacity after... - ANSWER subsequent and following days
of psychometric readings
factors to consider adjusting dehu requirement - ANSWER agreed upon deadline to
complete // power is less than adequate // occupancy of building during drying
(potential equipment shut off, frequent opening of doors, higher moisture load) //
schedule imposed by client (wanting to be open during certain hours) // required
pressure differential to achieve contaminant control
sizing desiccant dehu - ANSWER start with determining ACH - air changes per hour
detailed calc of dehu - ANSWER for advanced restorers
build out density considers... - ANSWER building's ability to circulate dry air
throughout & the amount of wall materials need to be addressed
weather impact factor considers - ANSWER outside weather and building's envelope
ability to keep outside air from coming inside
direct expansion systems - ANSWER circulates refrigerant though a cold evaporator
coil within the system that cools air stream that is delivered via insulated ducts
throughout building // indoor air is returned to be reconditioned // think roof top units
// lowest dew point is 43-45 degrees F
chilled water systems - ANSWER circulate conditioned water (cold/hot) through
the system // distributes air to individual fan/coil located in the building
ACH - ANSWER air change rate per hour // to calculate, find the volume, multiple by # of
air changes // convert to CFM by dividing by 60
