tornado shelter under slab with vent

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difowler1

Senior Member
I have a metal tornado shelter under the slab, residential. There is one 2"x2" vent pipe (box tubing) on the top of the shelter penetrating through the slab and into the wall of the home. The box tubing is 6" long. The customer doesn't want any new penetrations in the tornado shelter. They want a air vent attached to this vent pipe and an electrical wire ran into the shelter for power. I know there are some restrictions about running wire in a vent tube. Any Batman type methods I could use to do this legally? Other than the vent pipe, there is of course an access in the middle of the shelter for people to enter the shelter, but I couldn't run the wire into the shelter through the access hole.
 

difowler1

Senior Member
continued

continued

So we have the 2" x2" box tubing sticking up out of the shelter. They want to attach a 4" dryer vent hose to that and to run the vent hose up to the attic. They also want the wire for power ran down into the shelter with "no other penetrations". The power is for a plug and light in the shelter. I be back for explanations.
 

difowler1

Senior Member
another comment

another comment

I haven't started to research this yet. The only thing I can think of to start trying to research it, is I know there is some information about vertical and horizontal wiring through plenums. The dryer vent pipe is not a plenum though. Wondering where to begin.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
If running wire through the air vent would be allowed, I could at least see the inspector requiring a pipe wiring method rather than cable.
Run properly through the access door frame seems to work too, but that depends on the design of the hatch.
How about inductive coupling through the slab? :)
I do not feel particularly good about the dryer vent tubing through to the attic, since I could see it getting crushed if part of the house failed, cutting off the air supply. It is not necessary for a tornado shelter to be airtight with controlled ventilation the way a fallout shelter used to be built.
 

difowler1

Senior Member
emt?

emt?

Yes, I figured it would be better to run it in emt even though like you where saying, I don't know if an inspector would go for it. I don't like the dryer vent pipe either, or even any part of this thing, but of course it isn't possible to be a primadonna all the time.
 

cadpoint

Senior Member
Location
Durham, NC
My opinion, the owner is not going to let you do a proper job.

Run

Or, figure out the thickness of the bunker.

You'll need to drill through for a 1/2" pvc double ended threaded fitting,
they have pre-made six inch at Box stores in lawn gardening area.

Brush the hole clean of dust, put silicon sealant on the outside PVC and seal
insert let dry and seal both ends, lock rings and set boxes or EL's and continue runs.

You can put a battery back up light on a switch and have them turn that on, till the power
goes out and then still have 90 minutes of battery life once there's trouble.

And it all depends on local requirements, they will just replace battery ever three years!
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
I have a metal tornado shelter under the slab, residential. There is one 2"x2" vent pipe (box tubing) on the top of the shelter penetrating through the slab and into the wall of the home. The box tubing is 6" long. The customer doesn't want any new penetrations in the tornado shelter. They want a air vent attached to this vent pipe and an electrical wire ran into the shelter for power. I know there are some restrictions about running wire in a vent tube. Any Batman type methods I could use to do this legally? Other than the vent pipe, there is of course an access in the middle of the shelter for people to enter the shelter, but I couldn't run the wire into the shelter through the access hole.
The customer wants to put an obstruction in his air supply. Why is he waiting for a tornado someday when he can put a sock over his head today?
 

Fulthrotl

~Autocorrect is My Worst Enema.~
Yes, I figured it would be better to run it in emt even though like you where saying, I don't know if an inspector would go for it. I don't like the dryer vent pipe either, or even any part of this thing, but of course it isn't possible to be a primadonna all the time.

2" square opening is all that they have for air....? that's it?

bomb shelters in the 60's had a 6" tube, with a hand
crank blower to suck in air... breathing is a nice luxury.

if i had to make a tornado cellar, it'd have a bit of LED lighting
on a 12 volt system, and two 4" steel pipes up with 180 u turns
up on top, to keep crap out.... and both of them would have
4" muffin fans inside the cellar... one would be 120 volt, and
would run continuously to keep the air changed and keep dampness out,
and the other one would be on a 12 volt battery system that would be
there when the power went out... add some 12 volt LED lights for when
this thing is in use, and you are done.

air intake, air exhaust, forced ventilation, and light., and the airways
are something that won't get easily closed off when the house blows away.
 

jap

Senior Member
Occupation
Electrician
Mines had a 3" rigid stubup in the back for the air vent, which I extended PVC all the way through the roof and put a rain cap on it.
It also came with a 3/4" hole with a 3/4" rigid coupling welded to it go get the electrical into the shelter.
Evidently they missed this part or it got covered up with concrete before the pipe was run to it.

JAP>
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
I guess I have to ask...(since I live in Tornado Alley), why would you concern yourself with electricity in the bunker? The short amount of time you will be in it for a tornado to pass I am more than sure a well a small battery system would work fine for some illumination and so on. I would be more concerned about any obstruction to my air source before I would worry about any electricity in the bunker...but I guess thats just me.
 

grich

Senior Member
Location
MP89.5, Mason City Subdivision
Occupation
Broadcast Engineer
ICC500 702.1.1 requires 2 square inches of vent space per occupant, and that's if there are vents at the top and bottom of the shelter. It can come all from the top of the shelter if the vent space is increased to 4 square inches per occupant. Owner's idea ain't gonna fly either way.
 

jap

Senior Member
Occupation
Electrician
When you have small children having a light and a tv to watch it makes weather like that much more tolerable, not to mention the need for a circulation fan or dehumidifier that we've had to run as to keep the condensation out of it.

We've had trains of bad weather come over the house where they've slept in it for 4 or 5 hrs. If you make it not so scary for them they actually enjoy going down under instead of being afraid of it.

JAP>
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
When you have small children having a light and a tv to watch it makes weather like that much more tolerable, not to mention the need for a circulation fan or dehumidifier that we've had to run as to keep the condensation out of it.

We've had trains of bad weather come over the house where they've slept in it for 4 or 5 hrs. If you make it not so scary for them they actually enjoy going down under instead of being afraid of it.

JAP>
Do plan on just living and surviving the event those shelters are designed for...or just make them a neat club house. Guess I am old fashion, if the weather says get in the shelter...I am not sure I care about anything else other than a flash light, extra batteries, radio and...family.

The average time a "tornado" passes would leave you in the shelter a minimal amount of time. It was called a Tornado shelter in the title of the post and not a storm shelter for long term living conditions. Never the less...to each his own I guess.
 

jap

Senior Member
Occupation
Electrician
Do plan on just living and surviving the event those shelters are designed for...or just make them a neat club house. Guess I am old fashion, if the weather says get in the shelter...I am not sure I care about anything else other than a flash light, extra batteries, radio and...family.

The average time a "tornado" passes would leave you in the shelter a minimal amount of time. It was called a Tornado shelter in the title of the post and not a storm shelter for long term living conditions. Never the less...to each his own I guess.

I'm right there with you, however if my wife knows its going to be stormy, she'll take the kids down early so they don't have to walk out in the rains since its actually installed at the end of our detached garage, which I haven't gotten around to building a cover between it and the house yet.
 

difowler1

Senior Member
the end

the end

In the end the customer approved me putting a 12"x12" pvc junction box in the wall over the 2"x2" vent tube coming out of the shelter. I cut a hole in the box before placing it snuggly over the vent tube. Out of the top of the junction box i installed a 2" pvc pipe that is capped off in the attic. He could attach his air blower to the 2" pipe in the attic if he wishes. There is also a 1/2"pvc chase connected from a receptacle in the closet to the 12"x12" pvc junction box. So with a fairly clear conscious, I only did a pvc junction box and chases for them. He can run romex wherever he wishes when I leave. So thanks to persistance and a will not to do the crazy stuff they ask for, I came out fairly unscathed again.
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
My thought would be that when the tornado, that you are hiding in the shelter from, destroys the house, I'm pretty sure that you won't have power any way.
 

Barbqranch

Senior Member
Location
Arcata, CA
Occupation
Plant maintenance electrician Semi-retired
How will you get any air flow with just one opening?

Sent from earthquake country, where tornadoes just don't happen.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
How will you get any air flow with just one opening?

Sent from earthquake country, where tornadoes just don't happen.
That's what the fan is for.
Just like if you only have one wire to make an electric circuit you have to make the voltage really high. :angel:
Or maybe the return air flows through the ground?
More seriously, a partition in the duct to separate it into two ducts would be a better idea.
Or else leave the hatch open except during storms.
 
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