This 15′ 9″ 2″x4″ half scale model of our full sized dome product was subjected to a failure load at the University of Alabama’s large structure testing laboratory.
Interior attachment was thru a 1″ diameter grade 8 bolt and eyelet attachment on the points of the cupola in normal configuration.
Well secured at the bottom thru a 1″ steel plate with similar grade 8 bolts and eyelets connected to a jack under the floor which would pull it to “failure”
This occurred at 44,000 lbs.
The DOME didn’t fail…the scaled down straps pulled the short nails in the smallest of the strap test configurations. Our intent was to demonstrate the role the proper strapping played in increasing the strength of our domes.
Simply stated…that’s 6 to 10 TIMES stronger than standard framing, even allowing for 2×6 and 2×8 rafters!
After the test one side….
They get bigger…
This particular model is rated for any cat 5 hurricane just as you see it. Another layer of plywood and extra strapping and it becomes a full fledged tornado shelter. Fully FEMA compliant for wood framed shelters!
So let’s talk for a moment about those FEMA “compliant ” shelters.
Here are the various stages of our “World’s First FEMA 361G tornado shelter which doubles as our new manufacturing facility.
Our basic 2×6 domes already meet FEMA requirements for tornado shelters at 250 mph, so the approved specification for missile impacts is met by adding additional plywood and metal plate. Easy enough.
We did a little ballistic testing of our own this month by subjecting our metal reinforced shelter panels to impacts a little faster than your average FEMA flying 2×4 at 100 mph.
Backed off 25 yards and started shooting them.
We started with low power .22, then mid, then Yellow Jackets,then .22 magnum, no dents in the metal visible on back side after penetrating 1 1/2″ of plywood. Next up was 9 mm, then .41 SW.
Nobody had a .45 so we had to settle for what I was sure would do it…357 magnum from 8 1/2″ barrel.
Soft point .308 bent the heck out of it but it took Full Metal Jacket .308 to get through badly deformed. From 25 yards.
Independent lab confirmed results
cal/dia./grain/ft per sec/bullet energy/result/FEMA min/result
.22 65 1750 3079 no penetration 972 + 300%
9mm 115 1500 3893 no penetration 972 +400%
.41 SW 140 1100 6896 no penetration 972 +700%
.357 mag 125 1400 6397 no penetration 972 +700%
.308FMJ 165 2700 35868 penetration 972 +3700%
One Full Metal Jacketed bullet penetrated the steel inner liner of a New Age Dome shelter series panel, with an impact force 37 times greater than FEMA approved specs.
All other bullets were stopped from penetrating with a factor 3-7 times greater than approved specs, with all allowances made to show forces on even scale.
You can see how an impact load is transferred much the way a spider web absorbs energy. Anything pushing one way has a web of framing members pushing back.
And here we are…
The NEXT time somebody walks in my shop and asks me where I've built a FEMA compliant shelter before, I’ll tell them, “You’re standing in it”. Still got a few pieces of siding and trim going on, with dome 2 finished with a few pieces of trim remaining. Storm ready right now. As a matter of fact a few of the neighbors have sheltered there recently when the sirens went off as they often do in THIS tornado plagued town.
Consider these facts…
A study performed by Texas Tech and Colorado state university in 1998 demonstrated why a dome has a better ability to deflect wind.
A rectilinear of “box” structure is impacted by an F5 tornado at the rate of 400 lbs per square foot. NOT expected to survive a tornado strike at all. So you can reason out why the common thought for storm protection in box form is immensely thick walls. In short…Build a bunker. Ugly…and useful for one purpose.
To HIDE in.
A DOME is impacted by an F5 tornado at the rate of only 100 lbs per sq ft. So if your dome is rated for more than that you can reasonably expect it to survive and at have SOME damage from debris to repair. Our 40′ residential domes are rated at 250 MPH wind. Resilient!
Useful for community centers, or other practical purposes yet STILL possessing the structural integrity to shield it’s occupants from danger. Why rush to a shelter when you are safe at home?
Lets be honest…the odds of being struck by a tornado are far less than the more common problems with storms…wind driven debris or trees toppling.This tree caused incredible damage. This box could only take about 2-4 tons till it broke.
After tree removal. I decided to demolish the extension and start over with a longer garage . Do YOU see evidence of a giant tree on the house?Impact point was just to the right of the wire attachment. A regular box house would have been split in two!
So what do WE do when a 120', 55" thick white oak snaps off at the roots and lands on a dome house? We make firewood. That tree heated the house most of the winter
Our dome was impacted by a 120′ white oak tree in this same storm and subjected to an impact force of over 150,00 lbs. That’s 75 tons! Didn’t even come through the drywall!