You’ve decided you want a personal tornado shelter. Not only do I understand the engineering code requirements, I design shelters, I present on shelters, and I’ve witnessed the destructive power of tornadoes firsthand. But before we go any further, let’s get our nomenclature straight. The terms “Safe Room” and “Storm Shelter” are nearly synonymous in everyday language. However, safe rooms are built and operated in accordance with the FEMA recommendations. FEMA describes a safe room as providing “near absolute” protection. “Storm Shelters” are not intended to meet the more strict FEMA requirements. Rather, “storm shelters” are designed in accordance with ICC-500 and mostly applies to commercial construction. This article focuses on residential or small safe rooms.
Building a Safe Room
Your first stop in deciding to build a safe room in your home or small business is FEMA’s P320 document. It’s free to order or download, and targets homeowners, homebuilders, and small business owners.
Warning: The P320 book only covers recommendations and design assistance with safe rooms housing up to 16 people. If your business (or residence) needs to protect more than 16 people or falls outside the scope of the P320 document, then the Ohio Building Code requires additional architectural, engineering, fire safety, ventilation, and more to be considered. Consult your local building official.
FEMA offers a plethora of resources related to small safe rooms. FEMA can help you decide whether you truly need a safe room (spoiler – in the Midwest the answer is yes), where it should be located, and even offers pre-designed construction plans! Let’s explore what FEMA has to offer:
New Construction (New Shelter, New Home)
Included with the FEMA P320 book are construction-ready plans and details for viable storm shelters. All walls, ceiling, anchors, and even the foundation are designed and tested to act as a safe room. Even better, the FEMA construction documents offer solutions in concrete: concrete, masonry and wood. FEMA’s intention is that a homeowner can take these drawings, hand them to an architect or contractor, and as long as the builder sticks to the FEMA drawings, your safe room is compliant.
Renovation or Addition (New Shelter, Existing Home)
Adding a safe room to an existing home or business can be extremely complex and expensive simply because it’s not sufficient to reinforce existing walls or roofs. The weak link when it comes to the extreme forces created by tornados is in the connections – the bolts, the screws, the rebar, down to the smallest detail! A great option for adding a new safe room to an existing home or building is to create a whole new separate addition, a below-ground bunker somewhere nearby on the property, or even under the garage slab. In all instances, the local building official, an architect, or an engineer should be consulted.
Pre-Fabricated Shelters + Doors
Pre-fabricated shelters can offer a low-cost turnkey solution to adding a safe room to your home. The pre-fabricated unit can be cleverly installed in a closet, pantry or garage. The market for pre-fabricated safe rooms is not regulated nor overseen by a government agency, so be sure to fully research and vet the manufacturer and its product. To help consumers in finding reputable manufacturers, the National Storm Shelter Association (NSSA) maintains a recommended list of vendors on its website.
Doors are the common weak link in safe room design and operation. Simply put, we like doors to be easy to operate. However, in order to resist a 2×4 debris-turned-missile flying through the air at 100 mph, a safe room door must be made of extremely strong (and heavy) materials. More importantly, the door latches must be extremely strong. A normal, household door panel is no match for flying debris!
Helpful Link: The Texas Tech National Wind Institute tests tons of pre-fabricated shelters, residential doors, commercial doors, components, wall, etc. maintains extensive lists of those tests that consumers can use to vet shelter and door manufacturers.
A few things to keep in mind:
1. A door able to protect against such extreme forces are heavy and cumbersome to operate on a daily basis.
2. Doors meeting the FEMA requirements have to be rigorously tested by a nationally recognized agency like the Underwriter’s Laboratory.
3. The door must be installed exactly as tested and in strict conformance with the instructions.
4. Finally, the door hinges, latches and hardware should be regularly maintained so that it operates correctly in the time of need.
5. These points all add up to one important fact: safe room doors are very expensive!
While residential storm shelters are recommended in many areas of our country (all US states experience tornadoes), it’s up to you to determine if it’s the right decision for your family. Tornadoes can be deadly and unpredictable as we’ve recently seen in the aftermath of the destruction of communities like Joplin, Missouri. If you decide to invest in a storm shelter, be sure to research the manufacturer and install it exactly as it was meant to be.
Other Advice for Tornado Safety
Taking Shelter at Home
NOAA and Ready.gov offer many suggestions when it comes to tornado safety. If you are already home or inside a building when a tornado is imminent, great! Follow the NOAA guidelines to find a safe space and hunker down when a safe room is not accessible:
- As close to ground as possible
- Away from doors, windows and outside walls
- Small rooms: bathrooms, closets, under stairs, hallways
Taking Shelter Away from Home
If you are out and about, the best option is to take refuge in a nearby building. However, how do we know which nearby building will offer the best protection? FEMA created their P431 booklet to help determine the safest refuge area inside a building. In general, the safest building are those built of robust materials: concrete, concrete masonry (cinder blocks), and robust steel framing. Here’s some of my personal recommendations:
- Cast-in-place parking garage – You can tell these styles of garages because they typically have flat slabs and ceilings. All of the concrete is poured monolithically such that there are no joints to be seen. The columns are integral with the beams which are integral with the slabs. Park on the ground floor near an interior column and listen to the radio.
Shopping Malls – Shopping malls are usually built of steel construction and even have designated areas of refuge in restrooms, corridors or stairwells.
- Hospitals – Usually concrete or steel buildings inherently built a little more robust than usual. Hospitals also likely have a designated refuge area.
- “Big box” home improvement, home goods or grocery stores – These stores may look strong, but can actually be quite dangerous. The exterior walls are usually masonry that is very tall with long-span steel joists supporting the roof. Tall walls and long-span framing are very weak against strong wind pressures and often times collapse during very strong tornadoes. Also, all the building materials inside are can be come devastating projectiles.
- Warehouses or industrial parks – Yes, the walls are very thick concrete. But, these building suffer from the same problem as big box facilities. The walls are strong, but tall walls combined with the steel roof are a recipe for collapse during very strong tornadoes.
- Metal industrial buildings and barns – these buildings offer little protection and are usually completely decimated during an intense tornado.