# Toronados



## cda (May 23, 2011)

Does the ibc have requirements to design for toronados like areas prone to earthquakes????


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## High Desert (May 23, 2011)

The only place I found that mentions tornados is Section 423 for storm shelters. There are hurricane prone areas addressed in the code, which are based on prolonged winds and gusts. I suspect tornados are more difficult to assess what the wind speed and actual forces may be on buildings. So I think the best advise from the code is to find shelter.

There may be some local amendments to states in tornado alley.


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## brudgers (May 23, 2011)

The issues with designing for tornadoes are:

1. Most devastation occurs from F4 and F5 and the loads are so extreme that it quickly becomes cost prohibitive to design for such events (energy goes up as the square of wind speed).

2. Tornadoes are very limited in geographic scope and very infrequent - the odds of a building being hit by a tornado are extremely low when compared to the odds of a seismic event or hurricane in regions prone to them - which makes the economics even more questionable.


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## Mark K (May 23, 2011)

Would suggest that the damage due to tornados would be a lot less if the building was tied together.  Look what is required in Florida and other hurricane regions.

The problem is that many owners are penny wise and pound foolish.  Also many building designers and contractors do not want to admit that maybe they haven't been doing it right in the past.


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## Gordon (May 24, 2011)

Aside from the occasional safe room, practically nothing seems to be done to consider tornadic winds in new designs. SOMETHING would be better than nothing-- maybe those acres of lovely glass on your bldg aren't such a great idea...  oh well.


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## Coug Dad (May 24, 2011)

The IBC currently does not have requirements for when a tornado safe room is required.  They have design criteria if one is provided or required by local amendment.  Some cities and states have adopted shelter requirements for certain occupancies.


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## fatboy (May 24, 2011)

"Toronados"

Wasn't that the name of an Olds or Buick?

Sorry, couldn't help myself.......


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## brudgers (May 24, 2011)

Mark K said:
			
		

> Would suggest that the damage due to tornados would be a lot less if the building was tied together.  Look what is required in Florida and other hurricane regions.The problem is that many owners are penny wise and pound foolish.  Also many building designers and contractors do not want to admit that maybe they haven't been doing it right in the past.


Most tornadoes can be handled by a structure designed to withstand hurricanes because the wind speeds are of similar magnitudes. However, designing to withstand hurricanes adds significant costs to the construction of an SFR.

Designing for the most destructive tornadoes is cost prohibitive - and those are the ones which make the news.


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## mmmarvel (May 24, 2011)

fatboy said:
			
		

> "Toronados"Wasn't that the name of an Olds or Buick?
> 
> Sorry, couldn't help myself.......


Oldsmobile, had front wheel drive, heck of a ride in it's time.


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## High Desert (May 24, 2011)

I'm not sure what a building would look like that was designed to resist 300-400 mph tornado forces. Maybe 30 inch concrete walls with no windows?


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## Papio Bldg Dept (May 24, 2011)

cda said:
			
		

> Does the ibc have requirements to design for toronados like areas prone to earthquakes????


This link doesn't specifically address your question, but offers general guidance, and alternatives to more cost-prohibitive design strategies by using safe-rooms and areas of refuge.


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## Papio Bldg Dept (May 24, 2011)

Public Law 108-146 in 2003, Tornado Shelters Act, is kind of an interesting read as well.


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## Pcinspector1 (May 24, 2011)

High Desert,

No windows?

They call it a fruit cellar, and it works fine!  Don't let the codes screw it up!

pc1


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## pwood (May 24, 2011)

mmmarvel said:
			
		

> Oldsmobile, had front wheel drive, heck of a ride in it's time.


drove a 1970 model from san fran to ensenada mexico in 1970 in about 7 hours, shooting blue flames at times out the muffler. average speed about 100 mph. it was the middle of the night. amazing how some of us survived the wonder years! nice ride:mrgreen:


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## mark handler (May 24, 2011)

cda said:
			
		

> Does the ibc have requirements to design for toronados like areas prone to earthquakes????


Yes, It's called wind.....


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## Pcinspector1 (May 24, 2011)

I was told to order the 2012 International Green Fruit Celler Construction Code by the boss! "Lots of pictures!" you should get yours before there all gone!

2012IGFCCC

pc1


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## mtlogcabin (May 24, 2011)

> Oldsmobile, had front wheel drive, heck of a ride in it's time.


When I met my wife she had one with a diesel. Rode nice but a POS motor


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## fatboy (May 24, 2011)

Probably was the 350, all they did was refit the olds rocket gas motor as a diesel, ran great early on, not good in the long run. I had a Chevy truck with one........nice thing was, when the diesel finally puked, just go out and find the rocket 350, bolt-in installation. Got one out of a low mileage 442, now that was a nice motor!   OK, a bit OT again..........sorry.


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## Jobsaver (May 24, 2011)

mmmarvel said:
			
		

> Oldsmobile, had front wheel drive, heck of a ride in it's time.


http://en.wikipedia.org/wiki/Oldsmobile_Toronado


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## peach (May 24, 2011)

you really can't design against an F5 tornado.


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## DRP (May 24, 2011)

Look at the frequency though, the F4 and 5's make the nat'l news but the little ones are far more frequent and do the bulk of the damage. They are survivable and not that hard to build for, the same construction would save many of the structures around the big ones. Not that I'm advocating more codes, education would be my choice. We tend to say that all tornados are unsurvivable and in fact most could be built against. There were 6 not too far away recently, only one exceeded 135 mph. All did significant damage. Less than 10% of tornados are F3 or greater while approximately 70% carry winds below 112 mph.


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## Mark K (May 24, 2011)

They used to say that you could not design for the big earthquake.


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## brudgers (May 25, 2011)

peach said:
			
		

> you really can't  *[afford to]* design against an F5 tornado.


Fixed it for you.


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## brudgers (May 25, 2011)

Mark K said:
			
		

> They used to say that you could not design for the big earthquake.


And recent events in Japan indicate why.


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## TJacobs (May 26, 2011)

I'm not an engineer (and I don't play one on TV either) but aren't hurricane winds more straight-line as opposed to a tornado (swirl)?  Where is the egg man?  He can fix it with chicken wire...


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## pwood (May 26, 2011)

TJacobs said:
			
		

> I'm not an engineer (and I don't play one on TV either) but aren't hurricane winds more straight-line as opposed to a tornado (swirl)? Where is the egg man? He can fix it with chicken wire...


tj,

  the eggman and the walrus have left the room, koo koo ka choo!


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## FredK (May 26, 2011)

peach said:
			
		

> you really can't design against an F5 tornado.


Not sure about that.  The Hospital there in Joplin was close to the edge and was still standing.  Granted the windows were gone but the structure was still there.

I would guess the real issue is pressure differences. Wood doesn't stand up that well.


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## Mark K (May 26, 2011)

If you look at the damage in Japan what I believe you will see is total damage to houses from tsunamis but in many cases more substantial buildings survived the tsunami with damage primarily to non-structural elements.  When away from the tsunami I would expect many small buildings survived often with little damage.  I would expect that the buildings constructed following traditional practices performed worse than buildings that were engineered and constructed in accordance with the design.  This is what we have seen in previous earthquakes.

A 9.0 earthquake does not translate into a proportionally larger acceleration that what you will see  in an 7.0 earthquake.  The earthquake magnitude is related to the energy in the earthquake.

I realize that it is threatening to admit that we could see significant improvement if we made modes changes to our practices.


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## brudgers (May 26, 2011)

TJacobs said:
			
		

> I'm not an engineer (and I don't play one on TV either) but aren't hurricane winds more straight-line as opposed to a tornado (swirl)?  Where is the egg man?  He can fix it with chicken wire...


At ground level, winds are generally turbulent regardless of wind event.

In both, an open field will allow ground level winds to reach a higher velocity near ground than a built up area.


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## brudgers (May 26, 2011)

Mark K said:
			
		

> If you look at the damage in Japan what I believe you will see is total damage to houses from tsunamis but in many cases more substantial buildings survived the tsunami with damage primarily to non-structural elements.


Such as reactor cores?


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## Mark K (May 26, 2011)

brudgers

We are talking about buildings regulated by building codes.  The reactors structure survived the shaking and the tsunami.  The problems was the systems to maintain cooling did not survive undamaged.  While there will be some damage to some of the systems in typical buildings the continued operation of these systems are not essential to protect the inhabitants.  If the structure is intact it then becomes feasible to fix up the building.

You see a biased picture on the news because they forus on the damage.  If you look at the experience in California and Chilie you will realize that many buildings survived with little to moderate damage because of local codes and practices.


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## Mule (May 31, 2011)

What about storm shelters below ground level? We have an application for one as I speak.... What do you guys require on this type of installation?

Zoning????? Engineered???? Fresh air requirements???? I'm at a loss here!


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## Gordon (Jun 1, 2011)

Nuclear power stations in the US are mostly built to withstand EF5 tornados, including winds up to 360 mph as well as the wind driven missiles. This protection is provided to all safety systems, especially the cooling systems, spent fuel pools, and emergency generator diesel fuel storage. It takes at least 3 ft of high quality reinforced concrete, making it impractical for wide use. Not to mention the tornado dampers, intake shields, steel doors weighing thousands of pounds, etc.


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## DRP (Jun 1, 2011)

Mule,

I'm not saying I would, but some of the boys would just put some mason jars in there, call it a root cellar and probably not ask.


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## Architect1281 (Jun 1, 2011)

It can be done but you could be the only one standing

http://en.wikipedia.org/wiki/File:100_0587.jpg

and some remind me of Bedrock http://www.jdsdomes.com/why_build_them.html


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## Mule (Jun 2, 2011)

Well... I've been doing a little research and there are specifications for storm shelters. FEMA has some and there is an ICC 500 that has some regulations.

Here is what we've decided... No permit (since it's less than 120 sq. ft.), same setbacks as a swimming pool, Based on FEMMA they say not recommended in the 500 year flood plane be we are going not in the 100 year flood plain, fresh air supply, and engineered to withstand the loads (soil, water etc).


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## cda (Jun 2, 2011)

Drain????

So they do not fill up like a hot tub???


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## Frank (Jun 2, 2011)

Gordon said:
			
		

> Nuclear power stations in the US are mostly built to withstand EF5 tornados, including winds up to 360 mph as well as the wind driven missiles. This protection is provided to all safety systems, especially the cooling systems, spent fuel pools, and emergency generator diesel fuel storage. It takes at least 3 ft of high quality reinforced concrete, making it impractical for wide use. Not to mention the tornado dampers, intake shields, steel doors weighing thousands of pounds, etc.


April 12, 2011, one of our nuclear plants in VA got hit in April by a tornado that damaged the switchgear and power lines cutting the plant off from the grid.  Emergency generators came on and the plant went through emergency shutdown.  Surry Unit 1 was restarted soon after the power lines were repaired, Unit 2 was kept shutdown as it was scheduled to be shutdown shortly after the tornado hit for refueling.

Enviromental impact was a 200 gallon oil leek from a damaged transformer and a 100 gallon diesiel fuel leak from an above ground tank.

http://www.nrc.gov/reading-rm/doc-collections/event-status/event/2011/20110420en.html#en46761


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## peach (Jun 2, 2011)

Tornado speeds can exceed 500 mph; can't design to resist.. (well, I guess you can, but no one could afford to build it).  IMHO, tornado prone areas should design/build to hurricane standards, but they are fairly localized,  short duration, random events getting something into the code probably won't happen.


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## mmmarvel (Jun 4, 2011)

TJacobs said:
			
		

> I'm not an engineer (and I don't play one on TV either) but aren't hurricane winds more straight-line as opposed to a tornado (swirl)?  Where is the egg man?  He can fix it with chicken wire...


Um, not sure what you mean.  Hurricanes are a swirl, but a BIG swirl, they swirl in a counter-clockwise motion (north of the equator, opposite that south of the equator) and the 'right hand side' of a hurricane is called the 'dirty side', because that's where all the debris that it's sucking up from the clean side (I guess cause it's cleaning the landscape of whatever is on the ground) gets thrown out.  Hurricanes are as unpredictable regarding the path that they will take as tornadoes, but like a large cruise ship versus a speedboat, they don't change course on a dime.  Typically being on the 'dirty side' is much worse, basically due to the amount of stuff that it flying through the sky at you.

As for the talk about root/storm cellars.  If you live in a place like Kansas, it's a good idea, but if you live in a place near water, like our coast lines or like Japan, well, the cellar might protect you from the wind storms (hurricane or tornado), it might even be okay during an earthquake, but I don't think I'd like to be in one when a tsunami hits ... just saying.


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## brudgers (Jun 4, 2011)

mmmarvel said:
			
		

> Um, not sure what you mean.  Hurricanes are a swirl, but a BIG swirl, they swirl in a counter-clockwise motion (north of the equator, opposite that south of the equator) and the 'right hand side' of a hurricane is called the 'dirty side', because that's where all the debris that it's sucking up from the clean side (I guess cause it's cleaning the landscape of whatever is on the ground) gets thrown out.  Hurricanes are as unpredictable regarding the path that they will take as tornadoes, but like a large cruise ship versus a speedboat, they don't change course on a dime.  Typically being on the 'dirty side' is much worse, basically due to the amount of stuff that it flying through the sky at you.As for the talk about root/storm cellars.  If you live in a place like Kansas, it's a good idea, but if you live in a place near water, like our coast lines or like Japan, well, the cellar might protect you from the wind storms (hurricane or tornado), it might even be okay during an earthquake, but I don't think I'd like to be in one when a tsunami hits ... just saying.


Hurricanes generate tornadoes.


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