Cleaning up category 3 water intrusion can lead to a number of different protocols, mainly adapted from the IICRC standards.

Category 3 Water – That which is highly contaminated and could cause death or serious illness if consumed by humans. Examples: sewage, rising flood water from rivers and streams, ground surface water flowing horizontally into homes. There are two ways in which water enters a building as a result of wind storm damage:

The first involves falling or windblown rainwater that enters as a result of damage to roof components or wall assemblies. The second involves horizontally traveling ground surface water (Category 3) containing silt and soil contaminants that infiltrate into structures, generally through doors or around foundation walls. This ground surface water (storm surge) may accumulate to a depth of several inches or several feet. When structures are partially submerged or remain substantially flooded for weeks, far more elaborate procedures usually are required.

Most household microorganisms (fungi, bacteria) typically require five conditions for germination, growth, amplification and dissemination. Generally, they include:

• organic food source, especially cellulose (e.g., paper, wood), which are found in abundance in construction materials
• moisture, even high humidity (67% RH plus)
• moderate temperature – 68-86°F/20-30°C
• stagnant air
• time – several hours to several days

Anything that can be done to control or minimize these optimum conditions will prolong the time required for microbial growth.

With the above background information in mind, loss mitigation procedures may include but are not necessarily limited to:

A. Foremost, consider safety:
1. Structural Integrity – Before entering a storm or flood-damaged structure, consider structural integrity, which may be impacted by the force of the wind on, or the force of the water entering the structure. When in doubt, obtain an evaluation by a licensed and qualified builder or structural engineer before entering.
2. Ventilation – Fresh moving air discourages the growth and amplification of microorganisms. Open windows and doors and air the structure out thoroughly. It is highly recommended that ventilation be maintained during and following the restoration effort, or until damp areas can be contained and subjected to mechanical dehumidification (HVAC or specialized equipment). This reduces, but does not eliminate, inhalation of microorganisms.
3. Shock Hazards – Ensure that electrical shock hazards have been eliminated by turning off the supply of electricity (circuit breakers) to damaged areas. Anticipate that electricity may be restored suddenly without notice.
4. Personal Protective Equipment – Wear protective clothing, boots with steel or fiberglass shanks, and a hard hat. Protect yourself from injury or exposure to microorganisms. Wear protective gloves before handling contaminated materials. Splash goggles are highly recommended to protect and prevent microorganism entry through the eyes. An organic vapor respirator (paint respirator) is highly recommended to prevent inhalation of most microorganisms or spores.

B. Remove quantities of debris (silt, vegetation, floating objects brought in by storm surge), if present, with shovels, rakes, etc. Carefully clean all tools with appropriate detergents after use.

C. Identify the source of water and extent of wetting:
1. When wind-blown rain water enters a building, it is important to identify the route of entry and to trace its path, as possible, to identify all wet components (ceilings, walls, insulation, framing). Professional water restoration contractors, when available, have specialized water-detection equipment and may be available to assist in this determination.
2. In rising water situations, typically there will be a visible water line on drywall or paneling. However, water may migrate or wick upward within the wall material itself or within insulation behind the wall.

D. Remove unsalvable or wet materials:
1. When wetting is caused by storm damage and comes from overhead or around openings in the building envelope, and especially when power has been interrupted in hot climates, it is important to remove wet components, as possible, to expose pockets of saturation to air circulation before microbial growth can occur.

a) Begin at the point of water entry and trace the path of wetting, removing ceiling and wall components and insulation as you go.
b) Although it may be possible for professionals with specialized equipment to dry carpet, pad and subflooring materials, when damage is wholesale in an area, seldom will qualified contractors be available to respond for this work. Therefore, it is normally prudent to remove saturated carpet and pad.
c) It is highly recommended that solid or laminated wood flooring, or sheet vinyl be removed to expose pockets of saturation.

2. In rising water situations (storm surge with contaminated ground water):

a) Remove and dispose of drywall (Sheetrock®), paneling or other wall materials up to a point 15-24″ inches above the water line visible on the wall. If possible, stay within four feet of the floor to salvage as much wall material as possible, since drywall is usually installed horizontally in 4’x8’ or 4’x12’ panels.
b) Remove and dispose of wet insulation materials exposed during wall removal. Look for evidence of moisture wicking up insulation materials. Leave only wall framing components that are durable and minimally porous, and which can be cleaned and decontaminated with relative ease.
c) Remove and dispose of floor coverings; carpet, cushion, pad, felt and sheet vinyl, laminate, or tile flooring materials. Porous materials may absorb considerable quantities of water and contaminant, and non-porous materials may trap moisture to prolong drying. The inevitable result will be rapid microorganism growth, along with associated odor and health hazards. Hardwood flooring should be removed since contaminants and moisture will collect underneath in the flutes or hollow areas between the hardwood and the subfloor.

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