When it comes to water damage, you may hear our water damage technicians discussing two different terms used while describing a water damage loss – water damage class & water damage category. While these two terms may sound similar, they in fact are very different. In today’s post we’ll describe the distinct differences between these two common water damage terms and define them in full.
Water Damage Category refers to the range of contamination in water, considering both its originating source and its quality after it contacts materials present on the job site. Time and temperature can affect or retard the amplification of contaminants, thereby affecting its category. The water damage category is also affected by potential contamination, defined as the presence of undesired substances; the identity, location, and quantity of which are not reflective of a normal indoor environment; the contaminants can produce adverse health effects, cause damage to structure and contents, or adversely affect the operation or function of building systems.
Here we’ll describe the 3 specific categories of water damage, category 1, 2, and 3.
Category 1: Category 1 water originates from a sanitary water source and does not pose substantial risk from dermal, ingestion, or inhalation exposure. Examples of Category 1 water sources can include, but are not limited to: broken water supply lines; tub or sink overflows with no contaminants; appliance malfunctions
involving water-supply lines; melting ice or snow; falling rainwater; broken toilet tanks; or toilet bowls that do not contain contaminants or additives.
Category 1 water can deteriorate to Category 2 or 3. Category 1 water that flows into an uncontaminated building does not constitute an immediate change in the category. However, Category 1 water that flows into a contaminated building can constitute an immediate change in the category. Once microorganisms become wet from the water intrusion, depending upon the length of time that they remain wet and the temperature, they can begin to grow in numbers and can change the category of the water. Odors can indicate that Category 1 water has deteriorated.
Category 2: Category 2 water 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). Examples of Category 2 water can include, but are not limited to: discharge from dishwashers or washing machines; overflows from washing machines; overflows from toilet bowls on the room side of the trap with some urine but no feces; seepage due to hydrostatic pressure; broken aquariums; and punctured water beds.
Category 2 water can deteriorate to Category 3. Once microorganisms become wet from the water intrusion, depending upon the length of time that they remain wet and the temperature, they can begin to grow in numbers and can change the category of the water.
Category 3: Category 3 water is grossly contaminated and can contain pathogenic, toxigenic, or other harmful agents and can cause significant adverse reactions to humans if contacted or consumed. Examples of Category 3 water can include, but are not limited to: sewage; wasteline backflows that originate from beyond the trap regardless of visible content or color; all other forms of contaminated water resulting from flooding from seawater; rising water from rivers or streams; and other contaminated water entering or affecting the indoor environment, such as wind-driven rain from hurricanes, tropical storms, or other weather-related events if they carry trace levels of contaminants (e.g., pesticides or toxic organic substances).
On the other hand, water damage class refers to a classification of the estimated evaporation load and is used when calculating the initial humidity control (e.g., dehumidification, ventilation). The classification is based on the approximate amount of wet surface area, and the permeance and porosity of affected materials remaining within the drying environment at the time drying is initiated. Information needed to determine Class should be gathered during the inspection process. The Classes are divided into four separate descriptions, Class 1, 2, 3, and 4.
Here we’ll describe the 4 specific classes of water damage and how they’re defined.
Class 1 — (least amount of water absorption and evaporation load): Water intrusion where wet, porous materials (e.g., carpet, gypsum board, fiber-fill insulation, concrete masonry unit (CMU), textiles) represent less than ~5% of the combined floor, wall and ceiling surface area in the space; and where materials described as low evaporation materials (e.g., plaster, wood, concrete, masonry) or low evaporation assemblies (e.g., multilayer wallboard, multilayer subfloors, gym floors, or other complex, built-up assemblies) have absorbed minimal moisture.
Class 2 — (significant amount of water absorption and evaporation load): Water intrusion where wet, porous materials (e.g., carpet, gypsum board, fiber-fill insulation, concrete masonry unit (CMU), textiles) represent ~5% to ~40% of the combined floor, wall, and ceiling surface area in the space; and where materials described as low evaporation materials (e.g., plaster, wood, concrete, masonry) or low evaporation assemblies (e.g., multilayer wallboard, multilayer subfloors, gym floors, or other complex, built-up assemblies) have absorbed minimal moisture.
Class 3 — (greatest amount of water absorption and evaporation load): Water intrusion where wet, porous materials (e.g., carpet, gypsum board, fiber-fill insulation, concrete masonry unit (CMU), textiles) represent more than ~40% of the combined floor, wall, and ceiling surface area in the space; and where materials described as low evaporation materials (e.g., plaster, wood, concrete, masonry) or low evaporation assemblies (e.g., multilayer wallboard, multilayer subfloors, gym floors, or other complex, built-up assemblies) have absorbed minimal moisture.
Class 4 — (deeply held or bound water): Water intrusion that involves a significant amount of water absorption into low evaporation materials (e.g., plaster, wood, concrete, masonry) or low evaporation assemblies (e.g., multilayer wallboard, multilayer subfloors, gym floors, or other complex, built-up assemblies). Drying may require special methods, longer drying times, or substantial water vapor pressure differentials.
That pretty much sums it up. Now you know the differences in class and category of water damage. As always if you have any type of water damage problem, don’t hesitate to contact H2O911 for immediate emergency service.