AHAM – see “Assocation of Home Appliance Manufacturers” a standard used to determine how effective a dehumidifier is.

Air Filtration Device (AFD) – Depdning on the mode of use, an AFD that filters (usually HEPA) and recirculates air is referred to as an air scrubber.

Air mover -  A specialised mechanically operated drying unit that promotes evaporation. Air movers incorporate an electric motor, fan and specially designed housing for use in drying carpet, cushion, and subfloors or structural components (wood floors, walls, crawlspaces, etc.)

Antimicrobial – Literally, “against microorganisms.” A substance, mechanism, or condition that inhibits the growth or existence of an organism. (e.g fungi, bacteria, viruses and other organisms).

Bottom Plate – The lower part of a wall frame, which rests upon and is attached to the floor.

Bound Moisture/Water – Many building materials have the capacity to absorb and chemically bind water within their cellular structure. This water behaves differently in the drying process. For example, in wood, as the moisture evaporates out of the cellular structure into the pores, it equalizes as a vapor. In this process, vapor pressure plays a significant role in moving moisture out of the material. As the drying process beings to focus on this “bound moisture”, permeance factors begin to limit just how quickly the moisture moves to the surface of the material before it is able to evaporate.

BTU – British Thermal Unit, a measurement of heat energy: The quantity of heat required to raise the temperature of one pound of distilled water one degree Fahrenheit, at or near the temperature of maximum water density (39F/4C).

Bulk water/Unbound moisture – Excess or unabsorbed water resulting from a sudden water release. Bulk water usually is removed by draining, pumping or vacuuming.

Capillary action – The movement of a liquid through a slender pathway. It is caused by adhesion, cohesion, and surface tension in liquids and other contact with the solid pathway.

Refers to the range of contamination in the water, considering both its originating source and its quality after it contacts materials present on the job site. Time and temperate can also affect the quality of the water, thereby potentially changing its category.

  • Category 1 – Clean Water, water that originates from a sanitary water source and does not pose substantial risk from dermal, ingestion or inhalation exposure.
  • Category 2 – Grey Water, water that potentially contains significant contamination and has the potential to cause discomfort or sickness if contacted or consumed by humans. Category 2 water can contain potentially unsafe levels of microorganisms or nutrients for microorganisms, as well as other organic or inorganic matter (chemical or biological).
  • Category 3 – Black Water, water is grossly contaminated and can contain pathogenic, toxigenic or other harmful agents. Examples of category 3 water sources can include, but are not limited to: sewage; toilet backflows that originate from beyond the toilet trap regardless of visible content or colour; all forms of flooding from sea water; ground surface water and rising water from rivers or streams, and other contaminated water entering of affecting the indoor environment, such as wind-driven rain from hurricanes, tropical storms, or other weather-related events. Such water sources may carry silt, organic matter, pesticides, heavy metals, regulated materials, or toxic organic substances.
    • Determining whether it is safe or possible to decontaminate contents items on a category 3 water loss is determined by the porosity of the item in question.
    • Generally speaking most porous items would be considered as non-salvageable.
      Clothing and Household Fabrics can in some cases be removed, sanitised and cleaned back to pre-loss condition this would be determined on an item by item basis.

Cavities – Hollow spaces in walls, flooring, ceilings and fixtures, into which water can flow, wick or migrate and become trapped or inhibited from drying

Class of water is the initial determination of the amount of water and the likely or anticipated rate of evaporation based upon the quantity and type of wet materials in the affected space. Determining the classes of water is an essential part of calculating the amount of initial dehumidification capacity necessary to handle the potential amount of water that will evaporate within the affected area, and air movement for the drying process. Classes provide a point of reference to aid in the type, size and amount of equipment initially installed on a water damage restoration project. However, situations can arise that require adjustments to the type amount and size of equipment being used during the drying process. This information should be gathered during the moisture inspection of the affected areas. The classes are divided into four separate descriptions, class 1 being the least involved to class 4 being a complex or more involved drying project.

    • Class 1 – This class would generally be best described as having the least amount of water absorption and evaporation, only part of a room or area is wet or larger areas containing materials that have absorbed minimal moisture. Little or no wet carpet and/or underlay is present.
    • Class 2 – This class would generally be described as having a large amount of water, absorption and evaporation. An entire room or more is generally affected. Carpet and underlay maybe wet.
      Water has wicked up walls less than 60CM. There is significant moisture remaining in contents and structural materials; such as: plywood, particle board, plaster, structural wood, concrete and substructure soil.
    • Class 3 – This class generally contains the greatest amount of water, absorption and evaporation. Fully involved. Water may have come from overhead. Contents, ceilings, walls, insulation, carpet, underlay and subfloor in virtually the entire area are saturated. If water has not come from above it has wicked up walls greater than 60CM.
    • Class 4 - Speciality drying situations – Wet materials with very low permeance/porosity (Such as but not limited to hardwood, brick, concrete that have light deep pockets of saturation, which require very low specific humidity in order to dry.) These situations MAY require longer drying times than would usually be expected on a regular water damage, as well as special drying methods.


Crawlspace The enclosed ground area bounded by foundation walls located beneath an elevated floor, usually not excavated and finished, that allows access to utilities and other services. This is in contrast to basements and slabs on grade.

Containment A precaution used to minimise cross-contamination from affected to unaffected areas by traffic or material handling. Containment normally consists of polly sheeting, often in combination with negative air pressure, to prevent cross-contamination.

For the purpose of this Standard, Conditions 1, 2, and 3 are defined for indoor environments relative to mould.

Critical Barriers Isolation barriers are usually constructed of poly sheeting material over items such as HVAC registers, building openings, fixtures and other areas required to be sealed for controlled air flow.

Cross Contamination The spread of contaminants from an affected area to an unaffected area.

Dew point- The temperature at which condensation occurs on surfaces.


A coating or sealant formulated to be applied over an existing substance in a building that will provide a permanent barrier between the coated substance and the living environment. Mould should be removed, and should not be encapsulated. Fungicidal coatings and Mould-Resistant coatings are used after mould removal.  

Engineering Controls using methods, equipment or containment in such a manner that they limit the exposure of remediation workers and occupants to contaminants and prevent the introduction of contaminants surrounding uncontaminated areas and contents

Full Containment Normally is used when significant or extensive mould growth is present or suspected and cannot be effectively controlled and remediated with source and local containment methods. Full containment the entire room, or building section is designated as the work or containment area.

Grains per kilogram(GPK) – It is the unit used to measure the weight of moisture in air.  The number of grains per kilogram of dry air expresses the specific humidity of the air.

HVAC Heating Ventilation and Air Conditioning


HEPA High Efficiency Particulate Air/arrestance which describes an air filter that removes 99.97% of particles at 0.3 microns in diameter. (Ideal for filtering mould)


Hygroscopic  A material that readily absorbs and retains moisture or water vapour from air.


Hypersensitivity An exaggerated response by the immune system to an allergen. Often used incorrectly to describe individual health effects that are different or of greater magnitude than those observed in most individuals in response to expose to the same substance or environmental condition.


IAQ Indoor Air Quality


IEP Indoor Environmental Professional


IICRC Institute of Inspection, Cleaning and Restoration Certification

IICRC S500 Standard and Reference Guide for Profesional Water Damage Restoration

IICRC S520 Standard and Reference Guide for Professional Mould Remediation

Immunocompromised individual a person in whom one or more parts of the normal immune system is affected by a specific disease or condition, such that the person is at increased susceptibility to acquiring certain infections or otherwise defending the body against the effects of certain foreign substances. Common examples of diseases which cause immunocompromised states include: AIDS, effects of chemotherapy on bone marrow; multiple myeloma; Hodgkin’s disease; and inherited immunoglobulin deficiencies.

OHS Occupational Health and Safety

Moisture Meter An electronic moisture sensing device used to measure the internal moisture percentage of various construction materials, such as wood, plaster, masonry, etc. There are two general categories of moisture meters: penetrating and non-penetrating.

Mould Stain Remover- Removal of cosmetic mould stains so that they are difficult to see from the naked eye.

Permeance Factor – A measure of water flow through material(s) or specific thickness. Permeance factors (perms) specify the vapor flow in grains of moisture per hour, through one square foot of material surface, at one inc of mercury (1”Hg) of vapor pressure)


  • Porous
    Materials that easily absorb or absorb moisture and, if organic, can easily support fungal growth. (e.g., clothing and other textiles, padded or upholstered items, leather, taxidermy, paper goods, many types of fine art);
  • Semi-Porous

Materials that absorb or absorb moisture slowly and, if organic, can support fungal growth (e.g., unfinished wood, masonry)


  • Non-porous:
    Materials that do not absorb or absorb moisture or those that have been surface treated and do not easily support fungal growth (e.g., finished wood, glass, metal, plastic);

PPE Personal Protective Equipment

Principles of Drying – Underlying, broad based, general principles that guide and support professional drying. The four general principles are:

  1. Removing excess water (absorbing, draining, pumping, extracting),
  2. Promoting evaporation,
  3. Promoting dehumidification and
  4. Controlling temperature.

Psychometry – The study of the relationship between air, humidity and temperature and their effect on various materials and comfort levels (adj. – psychrometric).

Relative Humidity -  The relationship between air volume and the amount of moisture it holds at a specific temperature expressed as a percentage of that air’s total moisture holding capacity.

Remediate – Removal of contaminants to return surface(s) to condition 1

Source Containment - Generally used as containment to address relatively small or limited areas of mould growth or in combination with other engineering controls to reduce the amount of spore release.

Subfloor – The surface laid across floor joists and beneath the finish flooring or “Decking” material.

Truck mount – A powerful self-contained extraction cleaning machine with an independent power source (Usually an internal combustion engine) and water heating capacity, which does not depend on the electrical power or water heater within a building.