If there are septic tanks in a community, there can be shelters underground

[SoCalDem]

A viable underground shelter need not be a "traditional" basement


Anything underground can save your life.

They are not that complicated, and they surely save lives.

I am from Kansas, so I know a bit about tornadoes.. Our house was hit in 1968 .. (3 came thru between 1 AM to 3 AM)

You go below ground and you wait.. even if it's hot & sticky & there are spiders & bugs..or if it's a muddy dirt floor and there are no lights..and the kids are crying & the cat is yowling & the dog is whining & panting like a maniac..


if you value life, you have a BELOW ground shelter of some kind.. It's not a place you regularly hang out in,, you may never use it, and when you do, you may only be in the place for less than an hour...a wise use of your time.


Maybe you'll never use it, and it just sits there "mocking you" for "wasting" that money
simple:





interesting




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variations

[Gravitycollapse]

1. I bet the roof of that school bus would peel back like a sardine can.

Might want to go with the other options.

[SoCalDem]

2. That photo may have been before it was covered up :)

They may have re-thought their "design"..

[ScreamingMeemie]

3. Here, where I live, they need to dynamite the space.

You can do it (under your garage) but it's going to cost you almost 100K extra.

[SoCalDem]

4. there will always be exceptions, but I guess it just depends on luck

guts & how much a life is worth

[ScreamingMeemie]

5. Right now? Uninsurable healthwise...so I'm worthless. No worries.

It's definitely not worth 100K.

[htuttle]

8. Do you run water and sewer pipes above the ground there?

How does the city deal with it?

[ScreamingMeemie]

16. They are just below surface and often need to be replaced.

We are sand over dark clay here. I've lived in this house for 4 years. Twice, the county has come out to replace pipes along the street. Water main breaks are common. Taxes are high.

[loli phabay]

6. our plan is the cave out back, narrow entrance and only ten by twenty inside

Not comfy but with twenty feet of rock above i figure its safe as anything.

[SoCalDem]

7. and it's free too.. sounds like a plan..

Just don;t take a flashlight.. you may not want to see the critters that live there year round..

My husband always reminded me to have flashlights in the basement.. I told him I did not want to wake the spiders up

[loli phabay]

33. salamanders and lots of spiders, guess i will have to take the wet vac

[galileoreloaded]

9. This op is devoid of factual basis

And ignores physics. You need to understand boyuancy in areas with high water table as well as D loading.

[SoCalDem]

10. tell that to people who crawled out safely..

There are always LOTS of reasons to NOT do something proactive...Bear in mind that shelters are not designed to LIVE in.. they are a sanctuary for a one time lifesaving event.. The house may still be destroyed, the cars battered and blown away.. The shelter below grade is just that..emergency shelter..

[Fumesucker]

15. A full septic tank doesn't have buoyancy

An empty one, such as a septic tank used as a shelter, does float and will be literally pushed out of the ground in a high water table area.

I've seen entire swimming pools pushed right out of the ground when people drain them.

[Demo_Chris]

18. What is going on in that picture?! nt

[Fumesucker]

20. A drained swimming pool is rising out of the ground

It's the deep end coming up, notice the shallow end with the kiddie slide is still more or less at ground level.

[Demo_Chris]

43. Absolutely amazing. nt

[wercal]

23. That photo makes me worry about my tank's pump chamber

Typically its only got a foot or so of liquid in it.

But, this can all be designed for. I've designed 30 ft deep sewer pump stations, and put massive concrete collars on them to get to zero buoyancy. Sometimes we use small fiberglass pump stations, and bolt them to concrete weights. On large sewer clarifiers, we use a cone shaped brass plug, called a pressure relief valve, which pops up and lets groundwater in (btw-I don't know why swimming pools don't have this).

There is always a solution.

Now pardon me, I've got to go calculate how much water I need to keep in my septic tank pump chamber.

[1-Old-Man]

35. I've seen swimming pools, Septic tanks, and those concrete coffin containers float up

I used to build concrete swimming pools in south Florida, we had them float out of the ground occasionally. Septic tanks float out of the ground at job-sites all the time, before the building is occupied and the tank is filled. I've also seen both coffins and those concrete liners that coffins are sometime interred in float out of the ground too. When the ground water rises, for whatever reason, buoyant things are going to float. Same thing if they are in an unbackfilled hole.

[Isoldeblue]

13. Then how is it that tunnels are built under water?

There are hundreds of tunnels under water throughout the world, with heavy-duty use for trains, cars, etc.. Why can't there be simple, basic community and school tunnel bunkers built in high risk areas like in OK?

[SoCalDem]

22. Probably because there are always naysayers (pennypinchers) who convince

enough people that they :
1. cannot afford to
2. physics say it can't be done
3. god will protect you
4. pick any "argument" you want

there will be people who manage to build/buy/install them, and they will be saved..and many will open their shelters to the "grasshoppers" they know..

there have always been tornadoes, but it's only since the great migration south, and the suburbification of those areas, that we see so many more lives at stake than before..

50 years ago, farmer's fields & hedgerows would be torn apart.. Now those areas are jammed with trailers, manufactured-box houses and, little attention to safety of the dwellers.

[wercal]

17. I've considered using an empty septic tank

As a tornado shelter...and I even joke that I plan to jump into our 'in use' tank if a tornado comes.

Also, I've designed plenty of fiberglass pump units with boyuancy problems...there are usually spots on the bottom to bolt them to concrete weights....so these solutions don't seem outlandish.

And there's always above grade safe rooms.

Lots of options....one of them is bound to fit your situation.

[SoCalDem]

24. Yep.. If you put a concrete pad under it and bolted straps to hold it tightly maybe

If you want to have one, you will.. people who don't want one will rationalize why they "can't" have one and they will convince others to also not have one.. they may also be the one frantically knocking on the door of someone who has one..begging to be let in ..

[wercal]

30. No need to strap a concrete tank to anything

I've done lots of buoyancy calcs...something as shallow as this can reach zero buoyancy just by thickening the walls and the precast base section. I get a factor of safety by not including the weight of the soil above.

Some people are over-emphasizing the flotation problem....liek you say, they will rationalize why it can't be done.

I've got a basement anyway...but I've always pondered an additional level of protection, where my living room can't kill me by falling on my head.

[FSogol]

32. I agree. Every single gas station in this country has 2-3 USTs* and they are not floating away.

* = Undergound storage tank.

They hold them down with hold down straps connected to deadmen (large concrete anchors) or hold down slabs. Often the top slab is included in the calc. We recently put in 3 20,000 gallon fiberglass rain water harvesting UG tanks, holding them down with 8" concrete slabs under the tanks with tie downs.

[wercal]

34. Good Point

The same people who swear it just can't be done...probably drove over a tank at the Quicky Mart today.

I have seen above ground tanks though...there must have been some brief moment in time when code either required them or made them cost effective. Its not easy to measure the level in them, though.

[FSogol]

37. We did a bunch of ASTs (Above Ground Storage tanks) about 10 years ago.

Most were for clients that wanted to avoid costly secondary containment equipment. Federal laws toughened in the mid 1990s to require monitoring and secondary containment on USTs. Land is too valuable around us to waste it on above ground equipment, so that trend died off.

[wercal]

38. Thanks for the info

As an aside, one of my clients owned an apartment building...which burst into flames one night. Apparantly, the gas station across the street had a leaky tank, which slowly created an underground plume of fuel...it eventually reached the basement of the apartment building, and the furnace touched off the vapor.

The Dept of Health and Environment came and dug a trench on his property, which repeatedly filled with gas and water...they would pump it into a truck and take it off-site. My client had to pay for all of this - the theory being it was his property, so the bill goes to him. And it is left to him to sue the gas station later.

The tank had recently passed a pressure test, but they pulled it out of the ground...pin holes everywhere! Apparantly not enough to fail pressure test, but enough to leak alot of gas.

Anyway, I can certainly see the utility of secondary containment. I assume the monotoring wells at gas stations are in the secondary containment?

[FSogol]

39. Yes (on the wells), but that is the wimpiest type of monitoring.

Better versions are to use a double wall tank with interstitial space monitoring (most use Veeder-Root Monitoring System). Fuel lines are also required to have double wall pipe with the secondary containment draining back to the tank or dispenser sump where a sensor senses the presence of product. Tanks also have overfill protection devices.

When taking out old tanks, we always ask the bidders for a unit price on removing contaminated soil. Some projects remove truckload after truckload of soil for cleaning.

[wercal]

42. Ah, unit price is always good for those 'unknowns'

[SoCalDem]

46. well there is always this

[Yo_Mama]

25. Where I live

people don't have in-ground swimming pools because when it gets wet the water pressure is so high it will literally force the pool up out of the ground.

The only way to have an in-ground shelter where I live is to artificially build a hill in your yard, and of course very many people don't have the space NOR the money. Even if you do have the space and the money, it's often illegal due to EPA regs to take dirt from one part of your property and build it up. You have to have the stuff trucked in.

[lumberjack_jeff]

11. Umm.... septic tanks don't float with the water table. n/t

[SoCalDem]

12. I don't recall saying that they did

[lumberjack_jeff]

14. A septic tank won't float on the water table, a bomb shelter will.

The feasibility of a storm cellar/bomb shelter has no relationship to the feasibility of a septic tank.

[SoCalDem]

26. In a way it does..

The ones on tv who keep talking about the HARD clay in Oklahoma rationalize it by saying the ground is too hard..and at the same time too sandy (erodes).. they have many reasons, why not to... but I still maintain that there ARE people who manage to dig down into it (and have been doing it for hundreds of years)..

It's a choice.. have a safe place or not.. take your choice.

[NutmegYankee]

28. It's the high water table.

Any sealed structure will tend to unsettle and want to rise with heavy rains. If that cracks the shelter, then it may be flooded when the time comes to use it.

[wercal]

19. They might if they were empty

And if they are made of fiberglass, which is both lighter, and more water-tight, it is an issue.

But the fiberglass shelter could be bolted to concrete weights...which is a very typical thing to do with underground fiberglass tanks.

[lumberjack_jeff]

21. due to pressure from the water in the soil, septic tanks frequently implode when pumped out.

It is certainly *possible* to install a water tight "tank" in the ground to serve the purpose of a storm cellar, but they are impractical in many situations in which septic tanks are feasible.

[wercal]

27. I honestly have never heard of a septic tank imploding

I suppose it would depend on the soil type and the lateral earth pressures...

In my neck of the woods, the rule of thumb is 4" reinforced concrete is good up to 7 ft deep, and 6" reinforced concrete is good up to 15 ft deep...depending on the wall length.

As far as water tight tanks are concerned, I'm just looking at some of the OP's photos, and those things look to be made of fiberglass, which could be made watertight. And, being watertight, they would have to be weighted down to prevent floating.

They look like fairly shallow installations (10-12 ft)...one is circular which adds strength. It all looks very doable to me.

I know the owner of the local pre-caste company, and I've long considered getting with him to market his concrete septic tanks for storm shelters. He would do the casting, and I'd worry about getting a power supply ans small drainage pump to it...and do buoyancy calculations if its in a shallow water table. On something that shallow, I can usually get to zero buoyancy just by thickening the walls and making the base section thicker.

It all looks doable - and I think a shelter could be found for just about any situation - even above ground in rock areas.

[Yo_Mama]

29. A septic tank will be filled with fluid

Which better not bleeping be the case for your storm shelter, or it will kill you.

I think [SoCalDem] should go talk to a civil engineer with some experience in these matters. Empty septic tanks in my area can literally implode from the force of the water pressure. And in my area, when you see a rural house with a mound in the yard, that's where the septic drainage field is - it had to be built up because the water table is just so darned high.

[wercal]

31. Yoo-Hoo

I'm a civil engineer...and I drew the short straw so I also do small flows (residential septic).

You can weight down an empty tank - make the walls thicker, make the floor thicker, make the manhole riser taller, so more dirt is piled on the lid.

And its not necessarily the water pressure that can implode the tank, its the lateral earth pressure (which in clay soils is greatest when saturated).

But, similar to how a basement can withstand this pressure, so can tanks. Again, thicker walls, interior buttress, its all possible.

I do alot of elevated systems as you describe. They are usually because of shallow rock. If we encounter a high water table, we install a 'cutoff drain' around the perimeter...around 3 feet deep, and daylight it to the low side of the property. Just mounding up a system that drains to a shallow water table wouldn't be approved in my area...since the lateral field water would just leech out the side of the mound, if its really that wet.

All of the shelters in the OP look feasible to me, with a little planning and engineering.

[Blue Owl]

36. Are you referring to the GOP think tanks?

[Cleita]

41. Haha! Good one! n/t

[Cleita]

40. In "The Wizard of Oz", didn't Dorothy's family ride out

the tornado in a root cellar? It seems like it shouldn't be that difficult.

[SoCalDem]

44. My Aunt Effie had a nice root cellar. We kids always loved to go down there

She kept her "put-up" jars of food there, and potatoes & carrots..and old license plates & lots of fun stuff for kids to look at... Just a brick floor..packed dirt coated with "something" on the walls and brick steps leading down into it. Nothing fancy at all, but they rode our many tornadoes in it.. Solomon, Kansas.. house built in 18-something or other..

It looked a lot like this

[applegrove]

45. Anderson Cooper just said that people don't have basements in the Oklahomacity area

because they just get flooded. People decide to forgo basements because they are more worried about flooding than they are of tornados.

[Cleita]

47. I bet they change their minds.

They should take a page out of how the Dutch deal with it. They use windmills to pump the water. Oklahomans could do a twofer. They could build windmills for electricity and let them do double duty pumping water out of underground shelters, although, I believe a well built shelter wouldn't flood.

[gopiscrap]

48. It's all about priorities

are we willing to spend the money?

[RebelOne]

49. Not if you live in South Florida.

Sure, there are septic tanks, but they are only a few feet deep. No South Florida home has a basement. There is no way an underground shelter could be dug, as it would be flooded with water.