Flood and Water Leaks Extraction Information


Classes of Water Loss

There are several factors that describe water loss damage. The first is CLASS. The four classes are as follows:

  • CLASS 1: (least amount of water, absorbtion and evaporation): Water losses that affect only part of a room or area, or larger areas containing materials that have absorbed minimal moisture. Little or no wet carpet and/or cushion is present. [Simple point to remember: No wet carpet or cushion]
  • CLASS 2: (large amount of water, absorption and evaporation): Water may have come from overhead. Ceilings, walls, insulation, carpet, cushion and subfloor in virtually the entire are saturated. [Simple point to remember: Carpet & cushion wet - walls wet less than 24"]
  • CLASS 3: (greatest amount of water, absorption and evaporation): Water may have come from overhead ceilings, walls, insulation, carpet and subfloor in virtually the entire are saturated. [Simple point to remember: Carpet and cushion wet - water came from above]
  • CLASS 4: (specialty drying situations): These consist of wet materials with very low permeance/porosity(e.g. hardwood, plaster, brick, concrete, light weight concrete and stone). Typically, there are deep pockets of saturation, which require very low specific humidity. The types of losses may require longer drying times and special methods. [Simple poin to remember: Specialty drying situations]


Category of Water Loss

The category of water loss describes the amount of contamination in the loss area. Water category is the basis for decision making on materials which should be dried. It is important for determining safety procedures on each water loss.

Category 1

Water with no significant risk of causing sickness or discomfort is said to be Category 1 water or "clean". Generally, Category 1 water intrusions are the result of compromised sanitary water supply lines. In order for a situation to remain a Category 1, water must not have sat in a structure for more than 72 hours, and materials affected must be clean and well maintained. If odors are present in the structure, further investigation is necessary - until the source of the odor is found. Odors indicate that the cleanliness of the water is not Category 1.
[Simple point to remember: sanitary source wet for less than 72 hours]

Category 2

Water that does carry a significant degree of chemical, biological and/or physical contamination is said to be Category 2. Water sources that can result in Category 2 damage include: aquariums, waterbed leaks, toilet bowl overflows(that originate from the sanitary water supply yet contain urine from the bowl), dishwasher discharge, clothes washer discharge, and water that enters the structure from hydrostatic pressure (from below grade).

When structures are affected by Category 2 water, special steps and procedures are necessary in order to return the structure to a pre-loss condition. Cleaning procedures must be employed before the drying process can continue. At a minimum, affected carpet underlay (pad, cushion) must be removed and disposed of, and carpet must be thoroughly cleaned using a hot water extraction method.
[Simple point to remember: significant degree of contamination, must dispose of pad]

Category 3

When water intrusion results from a grossly unsanitary source, carries pathogenic (disease causing) agents, or when water has dwelled in a structure for more than 120 hours, it is said to be Category3. Examples of Category 3 water sources include: discharge from toilets that originate from beyond the toilet trap (from the sewer or septic system), and intrusions from the surface of the ground into the structure (flood waters). All affected porous materials must be removed from the structure and disposed of properly.
[Simple point to remember: grossly unsanitary, remove carpet, pad and affected drywall]


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Information Source: S-500 Third Edition, 2006, c IICRC