Arkansas ShelterSafe Room Program

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Arkansas Shelter/Safe Room Program

• This state program assists Arkansas home-owners
  who choose to install a shelter or safe room on
  their property. The program covers up to 50
  percent of the cost and installation not to
  exceed1,000. The statewide rebate program
  applies to persons who have installed safe rooms
  or in-ground shelters at their primary residence
  on or after Jan. 21, 1999. Safe room installation
  must meet FEMA Publication 320 or National
  Performance Criteria for Tornado Shelters
  standards.

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Arkansas Tornadoes by County
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Tornadoes in Arkansas

• The state has experienced 1,681 tornadoes between
  1950 and 2007,with 239 tornadoes that were F3 and
  higher.
• State of Arkansas ranked fourth in the nation in
  deaths and fifth in injuries.
• Average of nearly 30 tornadoes
• annually.

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Tornadoes in Arkansas

• On the afternoon of Feb. 5, 2008 a weather system
  moved across the State of Arkansas, resulting in
  severe thunderstorms, tornadoes and flooding
  across the state. According to the National
  Weather Service, this was the deadliest severe
  weather event in the state since March 1, 1997.
  One of the tornadoes tracked 123 miles, which is
  the longest track on record in Arkansas since
  1950. The tornadoes claimed the lives of 13
  people.

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Map showing the 2008 tornado track
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Safe rooms in residences

• A residential safe room costs anywhere between
  3,000 and 10,000. it is mandatory for the safe
  room to meet the requirements established by FEMA
  320 or meet the National Performance Criteria for
  Tornado Shelters.

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Safe Rooms in Residences

• A safe room is a reinforced room built in a new
  or existing above-ground structure that can
  provide protection during storms. A safe room is
  often a closet or
• bathroom that has been modified to provide
  occupant protection in the event of a tornado

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Commercially-Manufactured Shelters

• An alternative to the in-home safe room is a
  commercially-manufactured shelter that, depending
  on the type, can be installed above-ground, below
  ground or partially below-ground. In-ground safe
  rooms have no state regulations however, they
  must meet local codes. They cost between 1,200
  and 4,500. They must be constructed of a
  waterproof material, properly
• ventilated, and contain doors that meet the
  National Performance Criteria for Tornado
  Shelters.

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Commercially-Manufactured Shelters
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Continuous Load Path

• Structural systems that provide a continuous load
  path are those that support all loads acting on a
  building laterally and vertically (inward and
  outward, upward and downward). A continuous load
  path can be thought of as a chain running
  through a building. The links of the chain are
  structural members, connections between members,
  and any fasteners used in the connections (e.g.,
  nails, screws, bolts, welds, or reinforcing
  steel).

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Continuous Load Path
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LOAD PATH FAILURE
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Wood 2x4 launched at 100 mph
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Windborne Debris (Missile) Impacts
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Windborne Debris (Missile) Impacts

• Walls, doors, and other surfaces inclined 30
  degrees or more from the horizontal are tested at
  the design missile speed of 100 mph.
• Those surfaces inclined 30 degrees or less from
  the horizontal are tested at 67 mph.

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Debris Impact Criteria

• Underground shelters or portions of them with
  less than 12 inches of soil cover should be able
  to meet the same criteria as if the surfaces were
  exposed.

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Impact Resistance

• Wood Systems Must be attached using AFG-01
  adhesive and 8 wood screws penetrating at least
  11/2 and spaced not more than 6 apart.
• Sheet Metal 14-gauge steel sheet can resist
  perforation only when it is used as the last
  layer on the non-impact face on the interior
  (shelter side) of the wall. If sheet metal alone
  is relied on for missile impact protection, it
  should be 12 gauge or heavier.
• Composite Wall6- and 8-inch-thick concrete
• masonry unit (CMU) walls that are fully
  grouted with concrete and reinforced with 4
  reinforcing steel (rebar) in every cell can
  withstand the impact of a 15-lb 2x4 wood

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Wood Systems
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Sheet Metal Systems
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Composite Wall Systems
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Composite Wall Systems
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Reinforced Concrete Wall
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Roof Systems

• Based on the observed behavior of roof specimens,
  it is believed that roof designs that incorporate
  a uniform thickness (i.e., flat slab of at least
  4 with 4 rebar) provide a more uniform level of
  protection from large debris impacts, than a
  waffle slab, or ribbed slab.

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Single-Door Systems Less Than 36 Inches Wide

• Steel doors with exterior skins of 14 gauge or
  thicker. The minimum hardware reinforcement
  should be 12 gauge.
• Lighter-skinned steel doors may be used with
  modification. The modification is the addition of
  a 14-gauge steel sheet to either side of the door
  using 1/4X1 ¼ inch self-tapping screws 6 OC.
• No wood door has ever passed the missile test.
• However, by adding a layer of 14 gauge steel
  sheathing on either side the door will pass the
  test.

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Door Frames

• Sixteen-gauge steel door frames in either a
  welded or knockdown style are known to be
  adequate to carry design wind and impact loads on
  a single door

Welded Door Frame
Knock Down Style Frame
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Door Hardware

• Steel doors with supplemental latching mechanisms
  near the top and the bottom are required to carry
  design wind loads and to prevent an
  inward-swinging door from being knocked open with
  a well-placed missile.
• Three latching mechanisms and 3 hinges are
  required (6 pts of attachment) so that, if debris
  impacts close to one and destroys it, two will be
  left to carry the wind loads.

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Door Hardware

• Doors with two additional mortised, cylindrical
  dead bolts (with solid 1/2-inch-thick steel throw
  bolts with a 1-inch throw into the door jamb)
  above and below the original latch would meet the
  requirement of the wind pressure and missile
  impact tests. Deadbolts that are operable from
  the inside shall be keyed from the outside.

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Door Systems

• A three-point latching system operated with a
  single-action lever, built with heavy duty steel
  with a 1 solid bolt with a 1 throw, that
  activates two 1 3/8 solid hook-bolts will also
  pass the missile test

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Windows

• Testing indicates that glass windows in any
  configuration are undesirable for use in tornado
  shelters. It is therefore recommended that
  glazing units subject to debris impacts not be
  included in shelters or that they be covered with
  material that meets the standards for doors.

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Ventilation

• Passive ventilation is required for all
  residential shelters. This is defined as the
  non-powered air flow into and through the shelter
  envelope by way of openings that provide air for
  breathing. Openings must be a minimum of 4 OD
  and be protected to prevent intrusion of
  wind-borne debris.

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Flood Hazard Considerations

• The lowest floor of the shelter must be elevated
  1 foot above the base flood elevation from any of
  the flooding sources. All utilities or services
  provided to the shelter must be protected from
  flooding as well.
• Dont site shelters where the
• possibility of flooding is present.

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Other Hazard Considerations

• Hazardous materials
• Power lines
• Gas mains
• Fire

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References

• FEMA Pub. 361 ( Design and Construction Guidance
  for Community Shelters)
• FEMA Pub. 320 ( Taking Shelter from the storm
  Building a safe room in your home)
• To request a copy of this publication, call
  1-800-480-2520
• National Performance Criteria For Tornado
  Shelters
• Association Standard for the Design,
  Construction, and Performance of Storm Shelters