By Valerie Laprad
More and more often it seems, families in the South are scrambling to take cover from increasingly intense and dangerous storms. Anyone with good, healthy respect for these storms probably already know the basic things to do in such an event, such as taking cover in a basement or interior room on the lower level of your home. But sometimes, sadly, these actions are not enough to keep you and your family safe. Every year, tornadoes and straight-line winds injure and kill many people, even with adequate warning time.
According to the Federal Emergency Management Agency (FEMA), Tennessee is in Zone IV, or a “High Risk Wind Zone.” According to FEMA, the US has been divided into four zones that “reflect the number and strength of extreme windstorms. Zone IV has experienced the most and the strongest tornado activity.”
So, what can be done to reduce death and injury, not to mention the high level of anxiety which almost always accompanies the threat of an oncoming storm? FEMA suggests building a Tornado Safe Room and will
provide, free of charge, complete information on how to do so. These designs, based on decades of research, have been reviewed by FEMA, the Wind Engineering Research Center at Texas Tech University and by the
National Association of homebuilders.
FEMA explains that a tornado safe room “is an anchored, reinforced enclosure able to withstand high wind and flying debris. It is anchored to the ground and reinforced with either steel reinforced concrete or steel sheathing to make the walls and ceiling virtually puncture-proof.
Safe rooms are designed to withstand winds up to 250 miles per hour, as well as resist impacts from objects traveling up to 100 miles per hour, and can be built in either a basement or in an interior room on the first floor of a house.” Safe rooms can be installed while the home is being built or can be retrofitted in most existing homes for about the cost of remodeling a bathroom. In some instances, homeowners may qualify to receive low-interest loans for the addition of a safe room, as well as tax savings and lower insurance premium costs.
FEMA has developed a free booklet called “Taking Shelter From the Storm: Building a Safe Room Inside Your House” (Pub. 320) which also includes complete construction plans and specifications that you can hand to your contractor. You can order this by calling 1-888-565-3896 or by visiting their web site at www.fema.gov/mit/saferoom.
To get a better understanding of why you might need a safe room, FEMA explains what extreme winds can actually do. “To understand what happens when extreme winds strike, you must first understand that tornado winds are not constant. Wind speeds, even in extreme wind events, rapidly increase and decrease. An obstruction, such as a house, in the path of the wind causes the wind to change direction. This change in wind direction increases pressure on parts of the house. The combination of increased pressures and fluctuating wind speeds creates stress on the house that frequently causes connections between building components to fail. For example, the roof or siding can be pulled off or the windows can be pushed in.
“Buildings that fail under the effects of extreme winds often appear to have exploded, giving rise to the misconception that the damage is caused by unequal wind pressures inside and outside the building. This
misconception has led to the myth that, during an extreme wind event, the windows and doors in a building should be opened to equalize the pressure. In fact, opening a window or door allows wind to enter a building and increases the risk of building failure.
“Damage can also be caused by fling debris (referred to as wind-borne missiles). If wind speeds are high enough, missiles can be thrown at a building with enough force to penetrate windows, walls, or the roof. For example, an object such as a 2” x 4” wood stud weighing 15 pounds, when carried by a 250-mph wind, can have a horizontal speed of 100 mph and enough force to penetrate most common building materials used in houses today. Even a reinforced masonry wall will be penetrated unless it has been designed and constructed to resist debris impact during extreme winds. Because missiles can severely damage and even penetrate walls and roofs, they threaten not only buildings but the occupants as well.”
The sole purpose of tornado safe rooms is to protect lives and prevent injuries. In “Taking Shelter from the Storm,” FEMA goes on to explain some of the basis of shelter design. “Your shelter should be readily accessible from all parts of your house, and it should be free of clutter. To protect the occupants during extreme windstorms, the shelter must be adequately anchored to the house foundation to resist overturning and uplift. The connections between all parts of the shelter must be strong enough to resist failure, and the walls, roof, and door must resist penetration by wind-borne missiles.
“Extensive testing by Texas Tech University and other wind engineering research facilities has shown that walls, ceilings, and doors commonly used in house construction cannot withstand the impact of missiles carried by extreme winds. The shelter designs in [the] booklet account for these findings by specifying building materials and combinations of building materials that will resist penetration by missiles in extreme winds.
“The shelter designs, including both materials and connections, are based on wind speeds that are rarely exceeded in the United States. Therefore, a shelter built according to these designs is expected to withstand the forces imposed on it by extreme winds without failing.
Those forces may cause cracks or other signs of stress in the materials or connections used in the shelter, and they may cause materials or connections to yield. However, the intent of the designs is not to produce a shelter that will always remain completely undamaged, but rather a shelter that will enable its occupants to survive an extreme windstorm with little or no injury.”
The following ‘frequently asked questions,’ and much more, can be found on the FEMA web site at www.fema.gov and can help you decide whether or not to build a tornado safe room.
My house has a basement; do I need a safe room?
“Some strong tornadoes have resulted in loss of the floor framing, collapse of basement walls, and death and injuries to individuals in the basement. What constitutes an acceptable level of protection is an individual decision. The basement is the safest place to seek shelter for homes without a safe room. However, basements do not provide the same level of protection as a safe room. Basements are a good location to install a shelter or build a safe room but access for handicapped or physically challenged individuals may be limited.”
What is the cost of installing a safe room in a new home?
“Costs for construction vary across the United States. The cost for constructing a safe room inside a new house, which can double as a master closet, bathroom or utility room, is between $2,500 and $6,000 depending on the following factors: the type of foundation on which your house is built and the size and location of the shelter.”
Can I install a safe room in an existing home?
“Typically, due to foundation size and location limitations, a retrofitted safe room is usually installed as a separate addition to an existing home or as a detached structure. Sometimes, with proper foundation preparation, it is possible to install a safe room in a garage or a basement.”
Can a homeowner build the safe room themselves?
“A homeowner who builds a shelter should be skilled in building construction. Some pre-fabricated manufactured shelters are available that require less building construction experience to successfully build. In purchasing any shelter, the homeowner should ask for documentation that it meet FEMA’s recommendations.”
Where is the best location for the safe room?
“A small interior room above grade is the best location for a safe room. Safe rooms are often used for other non-emergency purposes. Bathrooms and large closets are a frequent choice. Because warning times for tornadoes can be very short, quick access to the safe room is important in choosing location. If the owners have any special accessibility needs these should be considered in the location and design of the safe room.”
How do I find vendors for shelters or safe room construction?
“The designs in FEMA 320 can be built by most residential contractors. The qualifications, and reputation, of any contractor can be checked by the homeowner for all projects. If you are unsure of any shelter product, you should contact your local or state emergency management office. FEMA can provide your local emergency manager assistance in answering questions. The Wind Engineering Research Center at Texas Tech University also provides technical guidance about shelters. Their toll free number is 1-(888) 946-3287, ext. 336.”
FEMA also adds that there are other things you can do to help protect your family. “Whether or not you decide that you need a shelter in your house, you can take two important steps to protect yourself and your family during a tornado: prepare an emergency plan and put an emergency supply kit together. If you decide to build a shelter, your emergency plan should include notifying local emergency managers and family members or others outside the immediate area that you have a shelter.
This will allow emergency personnel to quickly free you if the exit from your shelter becomes blocked by debris. You should also prepare an emergency supply kit and either keep it in your shelter or be ready to bring it with you if you need to evacuate your house. Some of the items that the emergency supply kit should include are an adequate supply of water for each person in your household, non-perishable foods that do not have to be prepared or cooked. If these include canned goods, remember to bring a can opener. A first-aid kit, including necessary prescription medicines, should also accompany an emergency kit, as well as tools and supplies such as a flashlight (do not bring candles or anything that lights with a flame), battery-operated radio, cellular phone or CB radio, extra batteries, wrench (to turn off household gas and water), clothing and bedding, and special items [like] formula, diapers, bottles, powdered milk [for babies and] contact lenses and supplies, extra glasses [for adults].
“You can get more information about emergency planning from American Red Cross (ARC) and FEMA publications, which you can obtain free of charge by calling FEMA at 1-800-480-2520. These publications include the following: Emergency Preparedness Checklist, FEMA L-154 (ARC 4471), Food and Water in an Emergency, FEMA L-164 (ARC 5055), Your Family Disaster Supplies Kit, FEMA L-189 (ARC 4463) [and] Preparing for Emergencies, A Checklist for People with Mobility Problems, FEMA L-154 (ARC 4497).
These publications are also available at the FEMA web site www.fema.gov and at the American Red Cross web site www.redcross.org.