Strength:

Huge trees topple in storms, so why shouldn't this?

Winds speeds in a storm are considered to be greatest at perhaps 30' above ground level. And fully-fledged trees have three things working against them that this shelter does not have: 1) Huge surface area, which equates to high drag, 2) Moving center of gravity and 3) High leverage. BTW, the 3D surface area of a single leaf is much more than one might expect due to its fractal geometry. On the other hand, a domed cylinder has absolutely minimal surface area per volume.

Are they "bullet-proof"?

Resistant to bullets.

Yes, to IAC Level III or greater. An M4 Carbine made these dents when shot from 30 yards into sample wall and door panels.

Can this shelter withstand an EF5 tornado?

For "near absolute protection" from tornadoes, including EF5 tornadoes, a shelter needs to meet the FEMA guidelines and ICC/NSSA Standard.

Has one of your shelters ever taken a direct hit?

Direct Hit by a Tornado

I wouldn't wish that upon any of my Customers, and there have been close calls in at least five states. Two weeks after this picture was taken the gentleman told me they felt secure as a tornado came to within a half mile of their Arkansas home. When it does happen, the shelter will stand straight and tall through it all. In one tornado alone there were 16 various above-ground shelters that all did their job, and none of them were constructed of 3/8" thick cylindrical steel!

Are the locks and door strong enough?

The Door and Locks are So Important

That's an important question. For so long, the door was the weakness of most any storm shelter. But the door on the New Day shelter, is no weakness. It is literally shaped like a Roman shield to deflect incoming hits. But no warrior could carry it for long since it weighs 144 pounds.