Safe room

[edit] Introduction

A safe room is a structure designed to provide protection in extreme weather events such as tornadoes and hurricanes. A properly constructed safe room will have a very high probability of shielding its occupants from injury or death during natural disasters associated with dangerously high wind speeds and forces.

[edit] Types of safe rooms

Safe rooms are sometimes referred to as storm shelters. The most common types of safe rooms are above ground, underground or in ground.

[edit] Above ground safe rooms

Above ground safe rooms are typically constructed from steel and fibreglass to protect the occupants from high winds. These structures are fixed to concrete foundations that serve as anchors. They must be rigorously tested to ensure that they can provide protection from windborne debris.

Above ground safe rooms are often constructed inside garages. These are typically made from reinforced materials such as cement, rebar and brick, although some can be made from repurposed materials such as modified septic tanks.

[edit] Underground safe rooms

Underground safe rooms are sometimes referred to as storm cellars, storm bunkers, hurricane cellars or tornado cellars.These structures may provide greater protection than above ground shelters, since the storm can only damage the top of the underground structure (while an above ground shelter can be damaged on its sides or can be blocked by debris).

Underground safe rooms are often constructed in cellars and are accessible from a covered stairwell. They tend to have a separate exit in the form of a door installed at an angle; this serves to prevent debris from piling on top and blocking access.

Storm cellars may not be practical in situations where navigating stairs could prove problematic for some occupants. The flood risk in certain locations may also determine whether or not a cellar is a suitable place for a safe room. It is possible to waterproof a cellar to some degree, but in areas prone to flooding, the basement may not be suitable for taking refuge.

It may not be possible to construct a storm cellar in urban areas due to planning restrictions.

[edit] In ground safe rooms

In some cases, it may be possible to construct evacuation facilities underground in a nearby hillside or on the flat ground. These structures are made by excavating enough space to install a freestanding unit made of concrete, steel, fibreglass or some other suitably strong material. Access is provided by way of a door (and a stairway if necessary); then the rest of the structure is covered with earth.

These structures provide additional protection, since they are not compromised if the overhead structure collapses or is otherwise damaged. They also provide inherent protection from windborne debris naturally afforded by the surrounding soil coverage.

[edit] Safe room considerations

Interior safe rooms within the cellar or garage have the benefit of being closer to the building occupants, but an exterior safe room - whether in ground or above ground in an adjacent location - may be easier to install for an owner of an existing building.

Chapter 2 of FEMA P-320 provides information to help people determine whether their dwelling needs a safe room. Building owners should ask themselves several questions when considering whether to install a safe room:

• What is my risk of tornadoes and/or hurricanes?
• What existing refuge options do I have if a tornado or hurricane occurs in my location?
• What level of safety am I comfortable with?
• How feasible is it to construct a safe room and what are the costs?

Safe rooms can be associated with a single dwelling, or they can be designed to serve several members of a community. According to the FEMA guidelines, “A residential safe room serves occupants of dwelling units and has an occupant load of 16 persons or fewer. A community safe room is any safe room not defined as a residential safe room.”

[edit] Related articles on Designing Buildings

• Basement and sewerage LEGO set.
• Basement excavation.
• Basement Excavation (Restriction of Permitted Development) Bill.
• Basement impact assessment.
• Basements in buildings.
• Basement v cellar.
• Basement waterproofing.
• Building evacuation.
• Escape route.
• Managing and responding to disaster.
• Place of safety.
• Restoration Stories: patina and paint in old London houses.

[edit] External resources

• FEMA, FEMA P-320, Taking Shelter from the Storm: Building or Installing a Safe Room for Your Home.
• FEMA, What Is The Difference Between A Residential Safe Room And A Community Safe Room?