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Dry and Safe

Left unchecked, mold can cause serious structural damage and illness and, in some cases, death.

What kind of damage can mold do to education facilities? You need only to look at recent headlines: classrooms closed down, students relocated — sometimes entire schools or residence halls have to be shut down due to this often toxic substance.

Left unchecked, mold can cause serious structural damage and illness and, in some cases, death. So it is important for schools and universities to act aggressively to prevent it from growing.

Most molds require a wet environment to survive. Often, this moisture comes from leaky roofs, pipes or appliances. Or it could occur naturally, from flooding or water runoff. It may stem from vandalism, such as a clogged toilet. Whatever the case, the water and moisture must be removed properly, and the structure needs to dry.

When water damage occurs, many schools will use a wet/dry vacuum to remove water from the floor. The custodian may use a fan to help the moisture to evaporate and spray some air freshener to combat odor problems.

That is not the proper way to handle water damage. While the visible water damage can be addressed, it is important to go deeper and prevent the problem before it begins.

Proper water restoration consists of removing the moisture, preventing or stopping microbial growth and drying the structure. Unless removal is done properly, serious structural damage can occur, and building occupants may become ill. Many health hazards are associated with water damage. Airborne fungi and bacteria increase substantially with humidity above 60 percent. So it is important to dry the building, not just the carpet. The walls, subfloor and ceilings may be wet even though the carpet is dry. Where moisture is present, fungi and bacteria can be growing in ceilings, subfloors and behind walls. Spores will become airborne, and may spread through a building via the ventilation system.

Stop the damage

After finding standing water, determine the source and stop it. Remove all safety hazards and if necessary, turn off power. Decide if the water source is clean, runoff or sewage. Standing water has three categories: clean, gray and black.

  • Clean water is potable water from sources such as a broken pipe or an overflowing sink.

  • Gray water is unsanitary water that will cause sickness if consumed. It could come from a toilet with no feces, a waterbed, an aquarium or draining washer or dishwasher. Clean water that has been standing more than 24 hours and runoff groundwater that is considered not contaminated is considered gray water.

  • Black water is unsanitary water that will cause severe illness or death if consumed. Examples: sewage backflow, seawater, flood water from river or streams, water that contains contamination or industrial chemicals, or gray water left standing more than 24 hours.

After determining the source and type of water, try to determine how long it has been left standing. If it has been standing long enough, it will cause structural damage. The water will be absorbed by the walls and will wick up the walls; the subfloor also will have absorbed water. No matter what class of water, you must remove it as soon as possible.

The custodial staff should apply an antimicrobial spray that is approved for carpets. Make sure the area is unoccupied. Now remove the standing water as soon as possible. If the floor is carpeted, it will need to be cleaned by using hot-water extraction. The hot water will aid in destroying germs. Disinfect the carpet again after cleaning it.

If the water is considered black water, the carpet should be extracted, disinfected, removed and replaced. Do not keep it under any circumstance.

For clean or gray water, clean and disinfect the carpet and dry it. Since most schools have direct glue-down carpet with no pad, one should be able to dry the carpet and not have to replace it.

If the glue becomes loose while wet, it will reattach to the carpet and the floor after it dries.

Getting dry

The carpet is going to help the drying process. It will wick up the water to the surface. When this moisture hits the surface it will evaporate and create a saturated layer of moisture called a boundary layer. To keep the carpet drying, this layer needs to be moved by airflow, usually from air movers or fans.

How many fans are needed? First determine how much air is needed to keep the water evaporating. To dry a 20-foot by 20-foot room, it will take 4,000 cubic feet of air per hour. A good rule of thumb is 200 square feet of surface area (including walls and ceilings) per fan.

A 20-foot by 20-foot room will need at least four fans to move the air and one dehumidifier to help lower the humidity and raise the air temperature to help dry the air.

Most buildings with a good HVAC system have a humidity range of 40 to 50 percent. This is a lot lower than the typical humidity outside, so don't open windows to dry.

If it is a warm day with low humidity, the windows can be opened to help dry the room. Be sure to watch the dew point. If the outside air is colder than inside, it can cause condensation that may even appear on the back side of drywall.

Use a moisture meter to see if the walls are dry. Make sure that the humidity in the affected room is the same as the rest of the building. Once there is equal humidity and the moisture meter determines the walls and ceilings are dry, the drying process is complete. In most cases, this will take two to three days.

Water provides a breeding ground for microorganisms to grow. Moisture and a temperature of 68°F to 86°F allow bacteria to reproduce every 15 minutes; one cell can become 70 billion in 12 hours. Fungi and mold also thrive in these conditions. Because the microorganisms like moist, stale air, it is necessary to alter these conditions. Extraction using hot water and high-alkaline detergent will destroy some microorganisms.

Killing odor

Water damage often will cause an odor. Usually there are two types of odors from water damage. The first will develop within 24 to 48 hours. That is a sour odor that comes from bacteria growing on wet organic materials.

The second type of odor begins in about 48 to 72 hours and is caused by mold spores whose growth is accelerating. At this point, it is starting to be a dangerous situation for humans.

The mold is feeding on organic materials. The molds are producing waste, and bacteria are feeding on the waste. The bacteria are producing ammonia, which produces a musty odor and will attack fabric.

If the mold and mildew have begun to grow before you have found the source of water, shut down the HVAC in this area to prevent the spread of mold and mildew to non-contaminated areas.

To stop the growth of bacteria and mold and stop the odor, eliminate the conditions that help the mold and bacteria grow. Do this by using an antimicrobial spray — about a gallon per 200 square feet — on the carpet and walls.

Also cool the surface temperature and add fresh moving air with fans. This will help retard growth. Removing the moisture with dehumidifiers also will aid in retarding microbial growth.

After the room is dry, if any odor remains, spray the carpet with a malodor neutralizing product, such as a pairing agent. A carpet that has dried in less than a day should not have any damage and should not have an odor, unless it is a residual odor activated by the water.

By using more air movers, antimicrobial products suitable for carpets and commercial dehumidifiers made for drying structures, schools will be able to save their carpets, dry the structure, stop odors and keep students from getting ill.

This type of investment may be expensive initially, but will save money in the long run. If it is not feasible to make this type of investment, consider calling in a certified firm in water restoration to handle water-damage emergencies. They are trained in cleaning and drying buildings properly so that everyone stays safe and healthy.

Weise is a zone manager with the University of South Carolina, Columbia, S.C.

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