More on Storm Shelters

If you have decided that you want to invest in a storm shelter, but prefer a pre-manufactured one rather than having a “safe room” constructed, we have listed some things to consider when you start to make your plans.

Things to Consider When Planning to Purchase a Storm Shelter

A storm shelter is a big investment. Our purpose is to make it easier for a person who is looking for the nitty gritty information they need to rule out the shelters that are not appropriate for their location, for their needs, for their price range and for the use to which they will put it. The accessories that are important for one family are not important for everyone. If you find yourself going to a shelter many times during the year, you might prefer a shelter that has a few more amenties than someone who uses it only a few times a year. If you are about to build a home, you might want to consider a “safe room” or a shelter that is installed beneath part of the home. Some families might want to have a shelter that does “double-duty” as a storage area for other things, like a cold cellar. These pages will get you started.

Considerations to keep in mind when looking at commercially made underground shelters:

  1. What kind of material is used in its manufacture? Shelters may be made of concrete, steel, fiberglass, or other materials. Each one has its advantages and disadvantages, for both installation and long-term use.
  2. What style would best suit our needs and situation? There are storm shelters that are meant to be built into a new home, there are storm shelters that are meant to be installed in an existing home, there are storm shelters that are meant to be installed in the ground adjacent to a home. Some manufacturers are marketing “double duty” shelters, that can be used for valuables or extra storage area.
  3. If you live in an area where you are affected by hurricanes(see map), you will want to use the shelter for protection from them as well. So you will need to consider the possibility of storm surge in determining whether or not you want an underground or partially underground shelter.
  4. How thick is the fiberglass/steel/concrete? Thick enough to withstand the stresses that will undoubtedly be put on it whether there is a tornado or not?
  5. Were engineers involved with the design or is this an offshoot of another business that makes a different product that is not subject to the kind of stresses a storm shelter has?
  6. What sizes are available?
  7. How many people can fit comfortably into the shelter?
  8. What provision is made for seating?
  9. What provision is made for lighting?
  10. What provision is made for ventilation, especially if the door is blocked for several hours?
  11. Is there storage space for emergency supplies like water, a first aid kit, etc?
  12. Does the entry to the shelter open outward, inward, or slide sideways?
  13. Is there provision for getting out if the door is blocked or a tree falls on it?
  14. How high is the water table in your area, and what provision is there to keep the shelter in position? If you have a high water table, you don't want water leaking into the shelter, nor do you want it bobbying up out of the ground.
  15. If I live on a flood plain that sees frequent high water, what provision has been made to keep flood water from entering the shelter?
  16. Is the shelter seamless, or are there seams that might allow water or soil in?
  17. How deeply does the soil freeze? If you live in a northern climate, you don't want the frost in the ground buckling or cracking the sides or forcing the shelter out of the ground little by little.
  18. How far down is the bedrock in your area? Shallow soils above bedrock may add considerably to the installation cost, although it doesn't prevent you from installing an underground shelter.
  19. Shelters may be partially sunk into the ground, then banked with soil. What is the cost of drawing in additional dirt to bank a storm cellar that is only half underground?
  20. What is the basic cost of the shelter?
  21. Can I have it shipped here and install it myself with local help?
  22. What “accessories” are available and what is the cost of each?
  23. What is the cost of installation if we have to drill through rock to put it underground?
  24. What is the cost to ship it to my location? The proximity to a dealer is often THE determining factor in choosing a shelter! Fortunately, there are a number of manufacturers with dealers in many states, so the choices now are better than they were a few years ago.
  25. What is the installation cost if there is no bedrock?
  26. How long a warranty is provided, and what does it cover?
  27. What circumstances might negate that warranty?
  28. What if I have a problem with it a few years from now--what kind of support do the company offer?
  29. Are there additional costs I haven't asked about, and if so, what are they?
  30. What is the amount of time it will take to complete the installation process?
  31. Will unwelcome guests like rodents, snakes, scorpions, etc, be able to get into the shelter and either live or even worse, die there?
  32. What kind of monthly/yearly maintainance is required or suggested?
  33. How long has the company been in business? The longer the company has been in business, the more likely it is that they have created a good product and stand behind it. And the more likely they are still going to be around if you do have problems.
  34. Ask for the names of previous customers that have shelters and speak to them about the performace of the product.
And ask yourself:
  1. Are there underground pipes, conduits, gas lines, sewer lines, or cables that will have to be considered in or near the location you want to put your shelter?
  2. Will their location have a part in determining which shelter is possible?
  3. Do I want to consider investing in a larger shelter, and purchasing it jointly with a neighbor(s)? Is the neighbor going to be there permanently -- or is another family member -- might be factors here.

Which is better...an underground shelter or an above ground shelter?

Pros for underground shelters
  1. it is always safer to be below ground level in a tornado
Cons for underground shelters
  1. they are more susceptible to stresses and strains if soil freezes in the wintertime
  2. they are more susceptible to floating because of a high water table
  3. they may be more expensive to prepare the site for if there is bedrock
Pros for above ground shelters
  1. require less ground preparation
  2. can usually be entered more easily, particularly by aged or disabled family members
Cons for above ground shelters
  1. may take up valuable space on the house lot

Which is better...entering an underground shelter through the house or leaving your house to enter it?

Pros for in-house entry into underground shelters:
  1. it is safer if the tornado is almost upon you
  2. it is more convenient than having to go outside
  3. it is less suceptible to invasion by unwanted critters
  4. it is easier to control access to by “visitors” like neighborhood children
Cons for in-house entry into underground shelters:
  1. if the tornado totally destroys your home, you may be trapped until your house debris can be cleared off the entrance to the shelter
  2. it cannot be easily installed in a preexisting home
  3. if it is not installed properly, it might heave out of frozen ground or float out of a waterlogged soil, doing bad things to the inside of your home

Should you lock(or even be able to lock) the door to a storm shelter?

That depends on:
  1. whether you store anything in it, and if those items are needed or valuable
  2. whether you have neighborhood children who use it as a place to play(or get into mischief)
  3. whether there are vagrants who decide to make it their home
  4. and most important of all...whether you (and everyone else in the family) can remember where you put the key! If you have only 15 seconds to reach and enter the shelter, having to unlock the door may be the difference between life and death.

Testing:

There is no law that requires a manufacturer to have their shelter tested. After the recent tornado outbreak in Oklahoma(May 3, 1999), though, residents who applied for and were elegible for a $2000 rebate(under FEMA’ Project Impact, designed to help victims rebuild after natural disasters) on the cost of a shelter were required to confine their choice of a shelter to approved manufacturers. Shelter manufacturers may or may not have had it done, as it can cost thousands of dollars, and may even require extensive reworking of material or design elements in the structure. However, if a company has had their shelter tested and approved by either Texas Tech or some other safety testing company/group, it probably indicates an intent to create a quality product. On the other hand, if a company hasn't had any testing, but has been in the storm shelter business for many, many years, they are probably doing something right!

It is logical that debris impact testing would be more important for above-ground shelters, and ground-stress testing would be more important for below-ground shelters. Since most communities would require a building permit for such a project, a family would have to have a building inspector examine the plans for the shelter, and what building inspectors require would probably vary from community to community...perhaps even requiring the approval of a professional engineer. For shelters following the FEMA safe-room, the plans in the booklet Seeking Shelter from the Storm would probably be sufficient.

Texas Tech University is the only facility approved by FEMA to do debris impact testing. However, professional engineering firms can do testing to determine the amount of stress a particular structure can withstand.

Dr. Ernest Kiesling and April MacDowell of the Wind Engineering Institute at Texas Tech have been kind enough to answer many questions for us, and send a list of those shelters that have been tested and approved by them. Not all these companies have web pages.



FEMA criteria:

The FEMA criteria for storm shelters includes wind loads and debris impact. It is a goal that shelter manufacturers should design for, but it is a certainly more relevant for above-ground shelters than underground shelters, and is aimed more at shelters that are designed for group or school use.

Obviously, above-ground shelters must be more resistant to flying debris than underground shelters(even though boards and steel beams, etc, have been known to be driven many feet into the ground in tornadoes), and underground shelters must be more resistant to the stresses of frozen ground and/or a high water table. The FEMA criteria point outs that the entryway for an underground shelter is the weak point in a tornado, so the door or hatch cover of the shelter should be able to resist both the wind load and the impact from flying debris. They make a number of suggestions for items to be present in the shelter that would be supplied by the homeowner, rather than the shelter manufacturer. They also point out special provisions for shelters that may be installed in areas susceptible to flooding or earthquakes. You can download and read the entire FEMA criteria from the FEMA server.

The FEMA site now has a document you can download on the performance criteria for tornado shelters. It is worthwhile reading! You can download it in Microsoft Word format here.

However, this is a good time to remind everyone that there are always “companies” that rush in after a disaster to take advantage of the victims of that disaster. It is sad but true. After Hurricane Andrew struck southern Florida, trucks crammed with jugs of tap water pulled into town, charging exhorbitant prices for something that, a day or so before, was not even considered valuable. After the ice storm struck Quebec, Canada in January, 1998, the same kind of thing happened. We heard of one person buying a whole truck-load of generators, then trying to peddle them to power-less Canadians at twice the price. There are companies that have products that can be “turned into” storm shelters. They have jumped into the shelter business, adapting these products somewhat. So go by the old adage, “Let the buyer beware!” If you have already decided that you are going to buy a shelter, ask the hard questions before you invest--because it really IS an investment.



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