When a Flood is Likely

When the conditions are right for flooding in your area there are a number of immediate steps that you should take:

After the Flood

Remember Safety. The better your plan, the less likely you'll have significant damage; but there will always be some cleanup necessary. Remember, the faster you perform salvage, the sooner that your collections will be safe and the sooner your institution will be back "in business." But human safety must always have first priority.

This means checking the safety of your building and its electrical system. Be sure that the power is cut off until a complete assessment has been made. You will also want to be sure that the gas (if used in your institution) is shut off. If you have a fuel oil or propane tank at your institution, it may have floated, breaking the connecting pipes. Even an underground tank can float! Turn off these fuel valves as well.

This also means taking care when you re-enter the structure. Don't smoke or use any sort of open flame. In fact, it's best to only use flashlights that are approved for use in hazardous locations. One example is the Survivor brand. Carefully check for falling ceiling tiles or sagging plaster or wallboard. You may need to poke holes in the ceiling to allow it to drain. Be sure to stand away from, not under, the ceiling and begin at the edge of the sag, gradually poking more holes closer to the center of the sag, until the water is completely drained. Be sure to step carefully. Water and mud make floors slippery -- and they can hid a variety of unseen hazards. Flood waters carry a variety of creatures, so be sure you check all closets, corners, cabinets, drawers, and hidden spaces for animals, rodents, and snakes.

You will likely want to be certain that you have the appropriate personal protective equipment (PPE). This will likely include books (with steel toes and inserts to protect against punctures), gloves (work gloves and waterproof gloves), goggles (to protect from splashes), any maybe tyvek suits (to help keep mud and other contaminates off your clothing). There are a number of suppliers, including Lab Safety and Grainger. There are a number of good sites that provide health information related to flood situations. One is provided by the CDC and provides an overview of flood recovery concerns and another has been developed by the University of Vermont. Both are worth careful reading.

Building Recovery. Ventilation is the most effective way to dry out structure interiors. While air conditioning and supplemental dehumidification work well, they are far more expensive. Heat should not be used since it will encourage mold growth. Open up interior doors and (if possible -- and assuming weather conditions are appropriate) exterior windows. Install high velocity air circulators. These are heavy duty, industrial fans that are intended to move large volumes of air on a continuous basis. Your goal will be to keep the air moving to not only facilitate the drying out process, but to also reduce the potential for mold.

Avoid using extension cords, if possible. If you must, ensure that the gauge of the extension cord is appropriate for the amperage of the fan and the distance. Always use a Ground Fault Interrupt when there is water. If you are using a generator to power your fans, there are additional safety issues, including grounding, carbon monoxide poisoning, and the use of gasoline. There are several good sites devoted to generator safety -- one is by the Consumer Products Safety Commission and another is by an Electric coop.

Check piers and foundations for lose of mortar, cracking, and leaning. You may discover that you need to shore up portions of the building. Using the assistance of a structural engineer or a licensed contractor, support unstable building components with temporary reinforcements. Strengthen foundations; and support floors or roofs as necessary.

Drain any water carefully -- and slowly -- from ground floors and basements.  Make certain that the water level on the interior doesn't fall below the water level outside or in adjacent rooms -- the resulting pressure could cause structural failure.  For basements it's best to pump the water down several feet, mark the water level and wait 24 hours. If the water level went back up over your mark, it is too early to drain the floodwaters. Wait another 24 hours, pump the water down, mark the level, and wait. When the water stops going back up, pump it down another 2 to 3 feet and again wait 24 hours. Continue this process until the water is entirely drained.

Shovel out mud and debris. Remove carpets and any pads (they dry very slowly and are impossible to adequately clean).  Floor covering other than carpet, such as vinyl, may curl at the edges and the adhesive may fail. Removal is often necessary. Other flooring, such as tile , generally survives, although the subflooring may not dry. As a result, even seemingly stable flooring may ultimately need to be removed. Wood flooring is also difficult to salvage, but with slow drying you may find it possible. You will want to dry to increase air circulation below the wood floor (in the crawl space), as well as in the occupied space.

Remember that electrical circuits will need to be dried, tested, and replaced as necessary by a licensed electrician. HVAC ducts that have been in water will likely need to be replaced if they were flexible ducts or made from either duct board or had internal insulation. If they are sheet metal and have external insulation, they can be cleaned and retained. Many appliances, such as hot water tanks and HVAC equipment, will likely need to be replaced.

Wallboard exposed to water for more than one or two hours will likely need to be replaced. Even if the wallboard seems to be in good condition it may be hiding pooled water inside the walls. It is usually a good idea to remove wallboard several feet above the flood line (wallboard wicks water up above the flood level).  This will allow the wall cavities to be dried and to have debris removed.  Wet fiberglass batt and cellulose insulation should be removed and replaced. Styrofoam insulation usually survives floods and can generally be hosed off. Wood timbers, like wood flooring, will need to dry slowly.  Drying plaster walls is especially tricky. You'll need to drill holes for drying (perhaps under moldings that you have removed) and be especially careful to dry the plaster slowly so as to minimize damage to its keys.

Never install new materials until the entire structure is completely dry. There is no "rule of thumb." In fact, what you will need to do is obtain a good moisture meter and diligently use it throughout the building. Only when all readings are normal (typically under 8% moisture), is it appropriate to begin replacements.

This provides just a quick overview. The American Red Cross has an excellent publication for modern structures and the NPS has produced a guide for historic buildings. These publications will provide additional details.

Cleaning and Disinfecting.   Keep in mind that there is usually a difference between cleaning and disinfecting. Cleaning removed mud and other soils, but does not necessarily kill bacteria and other micro-organisms. On the other hand, disinfectants are usually very poor cleaners -- they kill micro-organisms, but they leave behind most soils.  These recommendations are only for modern, non-collection material. Never use any of these chemicals on the materials in a historic house or on any collections without first consulting a conservator.

The first choice in cleaning is a nonsudsing household cleaner. Appropriate cleaners are nonionic detergents, typically found in laundry and automatic dishwasher detergents. Avoid anionic detergents since they are generally high sudsing. The first choice in disinfecting are household disinfectants, such as the quaternary, phenolic, or pine-oil disinfectants.   Keep in mind that these products all have different features. For example, quaternary products are not very effective where there is organic material present (the phenolic disinfectants are more effective in the presence of organics). In addition, all disinfectants must remain on the surface for anywhere from 10 to 30 minutes to truly disinfect. Alternatively you may use ¼ cup (2 ounces) of liquid chlorine bleach mixed in 1 gallon of water (make sure that 5.25% sodium hypochlorite is the only active ingredient).

Remember that in an institutional setting you will likely be required to have material safety data sheets (MSDSs) for any chemicals you may use in the clean-up. Be prepared ahead of time and make sure that your institution complies with OSHA's "Right-to-Know."

The Collections

The best guide we have found for drying collections is Betty Walsh's Salvage Operations for Water Damaged Collections. Rather than try to duplicate her excellent advice, just follow the link and get the information from her chart. Every institution should have copies of this document, printed on water resistant paper or poly  paper, available for quick reference.

If you still want more information on the recovery of different types of materials, check out COOL's extensive list of disaster resources.