Free Flashcards for the IICRC WRT Exam
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These free WRT flashcards cover the terms the IICRC Water Damage Restoration Technician exam is built on — the vocabulary behind WRT exam questions, from the ANSI/IICRC S500 Standard for Professional Water Damage Restoration. Categories 1, 2 and 3. Classes 1 through 4. GPP, dew point, vapor pressure, wet bulb and grain depression. Dry standard and drying goal. LGR and desiccant dehumidifiers, air movers, HEPA filtration and moisture meters. No login, no email, nothing to download.
The exam asks you to make decisions, not recite definitions — but you cannot classify a loss you do not have the words for. Vocabulary is the fastest part of WRT prep to lock down, and it is the part that makes everything else in the standard readable. Work the deck in short sittings rather than one long one.
Tap a card to reveal the definition, then rate it Again, Hard, Good or Easy. The deck reorders itself around your rating: an Again card comes back within a few cards, a Hard card a little later, and an Easy card goes to the back. You spend your time on the terms you keep missing instead of shuffling past the ones you already know. Sign in with a free account and your ratings save across devices; without one they last for the session.
Use the topic filter to drill one area at a time — psychrometry on its own is worth an evening. When the terms stop feeling unfamiliar, move on to the free practice test. From there, run real numbers through the GPP and dehumidifier tools, then read the certification guide for how the class and exam actually work.
Looking for IICRC WRT exam answers? That page explains why answer dumps fail and gives you practice questions with the reasoning instead. For how the class and credential work, including whether you can do WRT certification online, use the certification guide.
WRT flashcards deck
S500 glossary: every term in these WRT flashcards
The same terms as plain text, if you would rather read the list than work the deck. Each term links to its entry in the water damage restoration glossary.
| Term | Definition |
|---|---|
| Category 1 Water | Clean-source water that is not expected to cause harm through skin contact, swallowing or breathing. It can deteriorate to Category 2 or 3 with time, temperature and contact. |
| Category 2 Water | Significantly contaminated water with the potential to cause discomfort or sickness if contacted or consumed — dishwasher or washing machine discharge, toilet overflow with urine only. |
| Category 3 Water | Heavily contaminated water that can carry disease-causing organisms or toxins — sewage, rising groundwater, seawater, wind-driven rain from storms. |
| Category Deterioration | The downgrade of water from a cleaner category to a dirtier one caused by time, temperature, and the materials or contaminants it contacts. Category is assigned to the water as found, not only to its source. |
| Class 1 Loss | The smallest evaporation load — minimal wet porous material affecting part of a room, with little absorbed moisture. |
| Class 2 Loss | A significant evaporation load: an entire room of carpet and cushion wet, with water wicking up walls. |
| Class 3 Loss | The greatest evaporation load, with water typically coming from overhead so ceilings, walls, insulation, carpet and subfloor are all saturated. |
| Class 4 Loss | Deeply held or bound water in low-permeance materials such as hardwood, plaster, concrete, brick and stone, requiring specialty drying methods and longer drying times. |
| Grains Per Pound (GPP) | The weight of water vapour, in grains, held in one pound of dry air. The working unit for tracking drying progress — falling GPP in the drying chamber means the dehumidification is winning. |
| Dew Point | The temperature at which air becomes saturated and condensation begins. Any surface colder than the dew point will collect condensation, which is how secondary damage appears during drying. |
| Vapor Pressure | The pressure exerted by water vapour in air. Moisture moves from higher vapour pressure to lower, so the vapour pressure differential is what actually drives evaporation out of a wet material. |
| Relative Humidity | The amount of moisture in the air expressed as a percentage of what that air could hold at its current temperature. It changes with temperature even when no moisture is added or removed. |
| Specific Humidity | The actual weight of moisture in the air regardless of temperature, usually expressed in grains per pound. Unlike relative humidity, it does not move when you only change the temperature. |
| Wet Bulb Temperature | The temperature read by a thermometer with a wetted wick in moving air. The gap between wet bulb and dry bulb indicates how much evaporation the air can still support. |
| Dry Bulb Temperature | Ordinary air temperature measured by a thermometer shielded from moisture and radiation — one of the two readings needed to plot a point on a psychrometric chart. |
| Grain Depression | The difference in grains per pound between the air entering a dehumidifier and the air leaving it. It is the direct measure of whether the unit is still doing useful work. |
| Psychrometric Chart | A chart plotting the relationships between dry bulb, wet bulb, dew point, relative humidity and grains per pound, so two known readings give you every other property of that air. |
| Boundary Layer | The thin band of saturated, still air sitting directly against a wet surface. It stalls evaporation until airflow strips it away, which is the entire purpose of an air mover. |
| Evaporation | The phase change from liquid water to water vapour. It is driven by the vapour pressure differential and accelerated by airflow, heat and lower surrounding humidity. |
| Dry Standard | The moisture content of unaffected material of the same type in the same building. It is the benchmark the drying goal is set from — not a fixed percentage. |
| Drying Goal | The documented target moisture content that affected materials must reach, established from the dry standard. Drying is complete when the goal is met, not on a fixed schedule. |
| Drying Chamber | The controlled space, sealed off as far as practical, in which airflow, temperature and dehumidification are managed together. A smaller chamber dries faster with the same equipment. |
| Secondary Damage | Damage caused by prolonged exposure to elevated humidity rather than by direct contact with the water — swelling, delamination, corrosion, condensation and microbial growth. |
| Open Drying System | A drying approach that exchanges air with the outdoors, appropriate only when outdoor air is drier than indoor air and the structure and contents are not contaminated. |
| Closed Drying System | A drying approach that seals the structure from outside air and relies on mechanical dehumidification to control humidity — the default when outdoor conditions are humid or contamination is present. |
| LGR Dehumidifier | A low grain refrigerant dehumidifier that pre-cools the incoming airstream so it can keep condensing moisture at grain levels where a conventional refrigerant unit has effectively stopped. |
| Desiccant Dehumidifier | A dehumidifier that adsorbs moisture onto a chemical wheel rather than condensing it. It keeps working in cold and very low-humidity conditions where refrigerant units lose capacity. |
| Air Mover | A high-velocity fan directed along a wet surface to break up the saturated boundary layer. It accelerates evaporation but removes no water from the building on its own. |
| HEPA Air Filtration Device | A filtration unit capturing 99.97% of particles at 0.3 microns, used for negative pressure containment and air scrubbing on contaminated losses. |
| Penetrating Moisture Meter | A meter using pins driven into a material to measure moisture content directly, used to confirm readings found with a non-penetrating search meter before removal decisions are made. |
| Non-Penetrating Moisture Meter | A search meter reading a relative moisture signal near the surface without damaging it. Fast for mapping, but it can be fooled by foil, metal or dense backing. |
| Thermo-Hygrometer | An instrument reading temperature and relative humidity together, from which dew point and grains per pound are derived for daily drying logs. |
| Moisture Mapping | The documented record of where moisture was found, in which materials and at what readings, taken at the inspection and repeated daily as the structure dries. |
| Daily Monitoring | The routine of recording temperature, relative humidity, GPP and material moisture readings each day of the drying process — the record that supports the scope and the duration. |
| ANSI/IICRC S520 | The standard for professional mold remediation. Once you are managing containment and engineering controls for microbial growth, you have left the S500 and moved into the S520. |
| PPE Escalation | The principle that personal protective equipment increases with the category of water and the hazards present, from gloves and eye protection up to respiratory protection, coveralls and decontamination. |