Category 2 Water: Water containing a significant degree of chemical, biological and/or physical contamination and having the potential to cause discomfort or sick­ness if consumed by or exposed to humans. Category 2 water is also referred to as “gray water.” Gray water carries microorganisms and nutrients for microorganisms.

Gray water may include: Discharge from dishwashers or washing machines; overflows from toilet bowls with some urine (no feces); sump pump failures; seepage due to hydrostatic pressure; chilled and condensate water; and fire protection sprinkler water. Gray water may contain chemicals, bio-contaminants (fungal, bacterial, viral algae) and other forms of contamination including physical hazards.

Time and temperature aggravate Cate­gory 2 water contamination levels signifi­cantly. Gray water in flooded structures that remains untreated for longer than 48 hours may change to Category 3, black water.

Category 3 Water: Grossly unsanitary water containing pathogenic agents, arising form sewage or other contaminated water sources and having the likelihood of caus­ing discomfort or sickness if consumed or exposed to humans. Black water includes sewage and other contaminated water sources entering or affecting the indoor en­vironment. Category 2 water that is not re­moved promptly may be reclassified as Category 3 water.

Toilet back flows that originated beyond the toilet trap are considered black water contamination, regardless of visible content or color. Category 3 water includes: Ground surface water; and rising water from rivers or streams.

Such water sources carry silt and organic matter into structures and create black water conditions.

Removal
Excess Water Removal: Excess water removal is essential as the beginning point of restoration procedures. Removal of excess water may be achieved by physical means such as mopping or soaking up excess moisture from hard surfaces or furnishings. However, water removal usually involves the use of more sophisticated techniques and equipment such as pumps, or specially designed commercial wet vacuuming equipment.

Evaporation: Once excess water is removed, remaining water must be changed from a liquid to a vapor by promoting evaporation. Normally, this is accomplished efficiently with specialized air-moving equipment.

Dehumidification: Once moisture is evaporated from structural materials and contents into the air, the moisture must be removed from the air through dehumidification, or it must be externally exhausted.

Failure to dehumidify may result in substantial secondary damage and present a significant health hazard.

Temperature Control: Both evaporation and dehumidification are greatly enhanced by controlling the temperature in a confined environment. Additionally, microorganisms’ growth is temperature related. Thus, temperature modification and control is an important basic principle for safe, effective drying.

Monitoring: The damaged structure must be monitored starting with the initial assessment and evaluation, and throughout the restoration process. Monitoring procedures may include, but are not limited to the following: Temperature and humidity readings; updating drying progress status; and checking the moisture content of structural wood and other materials with a moisture meter.

When applicable, monitoring also must include checking equipment operation, work progress and indoor environment quality.

 Following the removal of excess water, a detailed inspection must be conducted that considers the extent of water migration, the types and quantities of affected materials and the degree of apparent damage. The information obtained may be used to analyze the extent of damage and to determine the job scope. Professional testing equipment and the principals of psychrometry must be used to formulate a plan to dry and restore, or replace both structural materials and contents.
A comprehensive inspection may include, but is not necessarily limited to, the following:
• Identifying and evaluating health and safety hazards;
• Determining the source of water;
• Determining the need to protect floor covering materials and contents;
• Determining the extent of moisture intrusion;
• Determining the job scope;
• Evaluating flooring materials;
• Evaluating inventories and/or contents items;
• Evaluating the HVAC system if affected;
• Assess other structural materials (walls, ceilings, etc.);
• Documenting preexisting conditions not related to the current loss (wear, urine contamination, delaminatinon, etc.); and
• Establishing drying goals.
Floor covering evaluation: It is recommended that a determination be made as to whether floor covering materials (e.g. carpet, cushion, vinyl, wood, laminates) are salvageable. Considerations may include, but are not necessarily limited to the following:
.• Construction integrity; and
.• Porosity and potential health effects from contaminants.
Disposition of floor coverings and the ability to salvage them will be deter­mined according to the IICRC Drying Standards.

Structural Materials: Throughout the restoration process, it is highly recommended that effort is directed toward anticipating secondary damage and attending to other structural components that may require drying, or demolition and replacement. This is especially important if water remains in contact with building materials longer than 24 hours, such as water on flooring in contact with gypsum board.

These components may include, but are not necessarily limited to the following: Ceilings, walls, built-in furnishings and fixtures, insulation and structural wood.
Personal Protection: Persons working in or around Category 3 water during the initial stage of decontamination, cleaning and biocide application must be equipped with personal protective equipment (PPE) including but not necessarily limited to the following:
. • Rubber gloves;
. • Eye protection;
. • Protective suit; and
. • Rubber boots.

An evaluation must be made to determine the necessity for respiratory protection. In the case of overhead hazards or contamination, hard hats must also be worn.

Standard Principles
The underlying principles that guided the development of these standards were:
1. The ambient conditions must be stabilized and be able to be held at normal room conditions;
2. The building materials must be returned to their equilibrium moisture content to prevent the active growth of fungal spores; and
3. The building materials must be returned to their pre-loss moisture state. When these three criteria are met, a building can be considered dry.
Drying services shall be considered sufficient when the following three conditions have been achieved:
1. The interior ambient conditions are at or better than normal room conditions (50 percent RH at 70° F);
2. The moisture in the building materials themselves will not support the active growth of mold and mildew; and
3. The building materials and contents will finish returning to equilibrium with normal room conditions by themselves
without further damage to them.
Hardwood Floors: Drying services on a hardwood floor shall be considered surfficient when all four of the following conditions are met.
1. The moisture content (MC) of the wood is decreasing.
2. All affected wood is within 2.5 percent of its normal moisture content as determined by actual measurement in a control point elsewhere on the same floor.
3. The differential of MC in wood from the top to the bottom is no more than 1 percent.
4. The building environment is stabilized and the existing HVAC system is capable of maintaining normal room conditions. Drywall: If drying procedures are not initiated within 24 hours of the initial water loss or dried within 72 hours, all wet drywall should be replaced. Drying services on drywall shall be considered sufficient when all four of the following conditions are met:
1. The moisture content of the drywall is decreasing.
2. All affected drywall is within 10 percent of its normal moisture content as determined by actual measurement in a control point elsewhere in the same building. (Example: Taking several readings in unaffected areas of drywall showed that the MC that should be expected in the building is 14 percent. Therefore, the maximum reading at the end of the job should be no more than 24 percent.)
3. The differential of MC in wood from the top to the bottom is no more than 1 percent.
4. The building environment is stabilized and the existing HVAC system is capable of maintaining normal room conditions. Concrete Block: Drying services on concrete block shall be considered sufficient when all four of the following conditions are met.
1. The moisture content of the concrete block is decreasing.
2. All affected concrete block is within 10 percent of its normal moisture content as determined by actual measurement in a control point elsewhere in the same building. (Example: Taking several readings in unaffected areas of concrete block showed that the MC that should be expected in the building is 10 percent.
Therefore the maximum reading at the end of the job should be no more than 20 percent).
3. Ninety-five percent of the affected concrete block area meets criteria one and two.
4. The building environment is stabilized and the existing HVAC system is capable of maintaining normal room conditions. Plaster: For the purposes of this Standard, drying services on

plaster shall be considered sufficient when all four of the following conditions are met.
1. The moisture content of the plaster is decreasing.
2. All affected plaster is within 10 percent of its normal moisture content as determined by actual measurement in a control point elsewhere in the same building.
3. Ninety-five percent of the affected plaster area meets criteria one and two.
4. The building environment is stabilized and the existing HVAC system is capable of maintaining normal room conditions. Concrete: Drying services on concrete shall be considered sufficient when all four of the following conditions are met:
1. The moisture content of the concrete is decreasing.
2. All affected concrete is within 10 percent of its normal moisture content as determined by actual measurement in a control point elsewhere in the same building.
3. Ninety-five percent of the affected concrete area meets criteria one and two.
4. The building environment is stabilized and the existing HVAC system is capable of maintaining normal room conditions. Carpeting: For the purposes of this Standard, drying services on carpeting may be effective if the following conditions are met.
1. The carpet is not wet with Category 1 or 2 water for more than 48 hours.
2. The carpet is not wet with Category 3 (black) water for any amount of time.
3. The building environment is stabilized and the existing HVAC system is capable of maintaining normal room conditions.
4. If 1 and 2 are not met, the carpet must be removed and replaced.

Insulation: For the purposes of this Standard, thermal insulation materials used in walls or ceilings cannot be adequately dried and reused. If insulation material is determined to be wet, it must be removed from the building. The area where it was installed must be thoroughly cleaned, disinfected and dried. New insulation may then be installed. ❑