Yesterday's work took a lot out of me.
To give you a sense of context, saying that I was "Installing amenities inside of a safe-room" will be accurate enough for you to have a picture in your head.
8" thick, steel-reinforced concrete walls and ceiling. It was an impressive structure.
The only weak-point that I could see were the doors.
One issue with doors for safe-rooms involves conflicting scenarios. Historically, the most likely scenario in Michigan involves tornadoes. They pick up heavy trash and skip it along the ground. The main challenge to the structure is not the wind but the hammering from the trash. Imagine an 8" round of solid oak firewood hitting the door, dead-center, at 100mph. The tornado in Oklahoma City in 1999 mowed the interstate guardrail off at ground level.
The ideal door for that situation would open outward and would have a lip or a sill on all four edges that it engaged.
A second scenario that merits consideration involves home-invaders. There are people alive in Israel today who waited out the incursion from Gaza in their safe-rooms. Bonus link.
There are two issues with that kind of door. One is that doors that open outward have hinges that are exposed to the outside so they are not secure against humans. They can simply pop the hinge-pins out and pull the door open. The other issue is that drifts of trash can wedge the door closed. The family could survive the storm but then must rely on rescuers to free them.
It is conceivable that structures outside of the safe-room could serve as trash-catchers; structures like large urns or soil-filled planters have the potential to slow or stop trash. Walls that turn a right-angle have the same potential.
The solution that I think this family will choose will be to have the entry to the safe-room face a load-bearing wall and to have the garage door (most likely direction of a structural breach) towards the rear of the safe-room. It is not a highly engineered solution but it is economical and provides a bit of additional security.
The vault and safe room doors I've dealt with have a shape or overlap on the hinge side that even if the pins are pulled, the door can't be opened without being unlocked.
ReplyDeleteJonathan
The door to the safe room I built in the tornado belt was 10" I beams welded together full length both sides.
ReplyDeleteI used 2" pipe set into concrete top and bottom for hinges, with smaller pipe with a center 2" collars and tapped for grease zirks.
We estimated it weighed 470 pounds.
It fit into I beam door frames and had sucker rod bolts that slid into the frame top and bottom.
It opened inward and I screwed old barn wood into the channels for looks.
Time for a visit to an abandoned missile silo / control capsule for ideas. Exterior hinges can be mitigated by the closing pins supporting the door as shown. Alternate escape paths can end subsurface or otherwise out of view so that they are not identifiable, albeit messy to open inward. Sounds like fun project.
ReplyDeleteERJ - sorry for the off topic, but it appears that the "Next Installment" link for the Cumberland stories is missing here: https://eatonrapidsjoe.blogspot.com/2023/12/the-cost-of-squirrel-meat-cumberland.html
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Anon
In the midwest - "Tornado Alley" - tornado shelters are built inside a house's garage, although some are outside in the yard. If in the garage, the good ones require cutting and repouring part of the concrete floor thicker and with deep footers to anchor the steel safe room to. Usual construction is 3/16 - 1/4" steel walls with a sliding door, although I've seen a couple made with welded 3/8" plate on a 1/2" base. The better ones include a jack inside to force the sliding door open if gets blocked by the house collapsing around it. Depending on what the customer wants, and is willing to pay for, different locking options can allow use of the shelter as a safe, albeit, with somewhat less security than a "real" safe, aka "residential security container." Generally, none of the tornado shelters are spacious because they're designed to get a family through a fairly short tornado threat, but it's common to have electricity inside for a light or two, no ventilation, though.
ReplyDeleteCompletely non-spatial ability to picture things, but it does seem like the suggestion you had about putting planters or some other item to catch trash at the front door makes sense.
ReplyDeletePocket door.
ReplyDeleteIf you want to really fortify, investigate Mr Vauban. Get out of the trajectory of direct fire weapons....that includes out of the penetration cone when someone does breach a layer. Ah yes.....layers. Physical barriers are only bargaining for time, whether it be a fire resistant safe, a tornado and flood shelter, or a defensive line: given enough time, the attack will get through. So be ready with disruptive means, and/or an alternate position to buy more time until the threat goes away or you hammer its face out its rear and burn the remains.
ReplyDeleteYou’re in a tough spot, Joe. Trying to fortify against humans, and against tornadoes - are two very different missions. The only viable option that deals with both is maybe bomb shelter or bunker. A very effective way to defend against human predation is to hide in plain sight. See how the gunnies are hiding their guns using false bottoms in furniture, and hidden compartments. Is that a viable option? A bunker with a camouflaged and concealed entrance?
ReplyDeleteWould steel bollards placed in front of door (but far enoughfrom wall to swing through ) solve the debris problem. Sloping bollards so that trash would be thrown over the structure.
ReplyDeleteOutward facing doors do expose the hinges. There are "security" hinges who's pins cannot easily be driven out. They can still be cut off with an angle grinder or sawsall. If the jambs are secure enough, you can install pins through the hinge plates that engage when the door is closed. Even more secure is barring the door and/or retractable pins on the periphery as in a safe, but these can only be engaged and disengaged from the inside... possibly a feature.
ReplyDeleteAnd of course, for any "safe room" there is the potential of "siege". There should always be at least two means of egress. Ideally one should be unknown to the enemy, and provide egress beyond the siege perimeter, such as a tunnel.
My worry was the house blowing down around us and then catching fire and being locked in by a outward door swing. Woody
ReplyDeleteThe mouse and rabbit do not trust themselves to one opening.
ReplyDeleteSliding doors. With, as noted above, a jack or other method to force them should they become jammed (Not a bad idea for outward opening doors either.....)
ReplyDeleteBut also, some other method of egress is a must...be it a tunnel with a concrete slab over it (again, with a jack to move it) or other somewhat secure (but camouflaged) cover....Ideally fairly far from the main (and obvioush-ish) entrance. My tunnel has a hidden entrance, a secure door, then another secure door part way down the tunnel. With, I might add, a jog in it for blast and bullet deflection.
A jog is also good against radiation.
DeleteTWO entirely different requirements... Safe room and tornado shelters have different door requirements. Innie vs outie...
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