The four classes below help to determine the amount of water remaining in the structure after physical extraction has been completed.
Knowing the classification of water loss helps the restoration professional determine what types of equipment will be used and the drying conditions that should be achieved.
Class I – Slow rate of evaporation
The least amount of water or minimum amount of moisture that can be held in the remaining materials.
Characteristics of a Class I water loss include:
- Damage is confined to a small area.
- Contains low-permeance and/or porosity materials: Plywood, particle board, structural wood, VCT, or concrete.
- Little or no wet carpet, or carpet pad is not present.
For this type of loss we will seek to achieve drying temperatures that remain low within the 70° – 90° degree range for the entire job.
Class II – Fast rate of evaporation
More water or water losses where the majority of the structure contains saturated carpet and carpet pad.
Characteristics of a Class II water loss include:
- Water has wicked up walls less than 24 inches.
- Moisture remaining in structural materials: plywood, particle board, structural wood, VCT, or concrete.
For this type of loss we will seek to achieve drying temperatures that are as high as possible, within the 70° – 90° degree range for the first 36-48 hours, than drop it as low as possible within the 70° – 90° range for the remainder of the job.
Class III – Fastest rate of evaporation
Water may have come from overhead.
Characteristics of a Class III water loss include:
Ceilings, walls, insulation, carpet, carpet pad and sub floor in virtually the entire area are saturated.
For this type of loss we will seek to achieve drying temperatures that are as high as possible, within the 70° – 90° degree range for the first 36-48 hours, than drop it as low as possible within the 70° – 90° range for the remainder of the job.
Class IV – Specialty Drying Situation
These losses involve wet materials with very low permeance or porosity such as hardwoods, sub floor, plaster, brick, concrete, or stone.
There are deep pockets of saturation that are normally dried as Class I, but require the use of a desiccant or low grain refrigerant dehumidifier to achieve very low specific humidity (GPP).
Class IV situations require a custom drying plan that fits the needs of the job.
