# Observation Tower Use Classification



## Weston (Sep 15, 2018)

Hi. I am from the Northern Mariana Islands residing on Saipan and the Government is looking to construct a 2 story observation tower atop a cliff.  Adopted code is the 2009 IBC. I am very familiar with the code but I am having trouble finding the appropriate use and occupancy classification for this structure - I initially was thinking something along the lines of an A or U occupancy.  Appreciate any help and advice. BTW, this is my first time to post a question but I have used this forum to really help me with countless code inquiries. Thanks in advance.


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## mark handler (Sep 16, 2018)

Observing what?
Outside recreation?  A
Less than 50 _Business operation? B


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## Weston (Sep 16, 2018)

mark handler said:


> Observing what?
> Outside recreation?  A
> Less than 50 _Business operation? B


It would be outside and would be for business. More of a tourist hotspot. Intended purpose is to be able to see the ocean and have a birds eye view of other tourist sites of the island.


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## mark handler (Sep 16, 2018)

More than 50 people at a time?


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## cda (Sep 16, 2018)

How many sq feet

Occupied on more than one level?


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## JBI (Sep 17, 2018)

'Towers' are specifically listed as 'Utility and Miscellaneous Group U'.
Lacking more information about the intended occupant load/square footage, etc, it would appear that 'U' is appropriate for a tower.


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## ADAguy (Sep 17, 2018)

How will the tower be accessed? elevator
With or without restrooms?
Any parking?
How do you arrive at the building?


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## mark handler (Sep 17, 2018)

*If the "tower" Has Amenities, like dining, it can be a "A" or "B" 
Still do not Know size....*


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## Builder Bob (Sep 17, 2018)

I agree, not sufficient information provided - unconditioned space, conditioned space, public, security, etc. If public is invited for tourist trap - then it shoul d be a A or a B, if it is for agriculture uses or for security, it might be a U


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## ADAguy (Sep 17, 2018)

Patience, in another time zone (smiling)


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## mtlogcabin (Sep 17, 2018)

If it is strictly an observation tower that people use for a few minutes and then move on I would use the "U" occupancy simply because no plumbing facilities are then required.
Basically it is just a raised deck unless you are providing other amenities within or on the structure

302.1 General..........Where a structure is proposed for a purpose that is not specifically provided for in this code, such structure shall be classified in the group that the occupancy most nearly resembles, according to the fire safety and relative hazard involved.

SECTION 312
UTILITY AND MISCELLANEOUS GROUP U

312.1 General.
Buildings and structures of an accessory character and miscellaneous structures not classified in any specific occupancy shall be constructed, equipped and maintained to conform to the requirements of this code commensurate with the fire and life hazard incidental to their occupancy. Group U shall include, but not be limited to, the following:


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## Builder Bob (Sep 17, 2018)

May be true, but a raised deck over 750 SF is an A occupancy; and that is being generous at 1 person per 15 sf net  such as with table and chairs.


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## mtlogcabin (Sep 17, 2018)

I don't think it matters what you call it as long as the structural and egress is designed to a high number
federal and state Parks are full of observation decks that have no other facilities available at that location. Call it an "A" and restrooms will be required and that will trigger ADA for them.


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## Yikes (Sep 19, 2018)

Side comment while we await answers from Weston:
In our local mountains, we had a vehicular bridge that was built many years ago, but the highway project leading up the bridge was abandoned.
The bridge was never classified as a building.  Hikers would go to it and use it like an "observation tower" to look down into the river canyon below.

After a number of years, the government agency that owned the bridge sold it, along with the land under the abutments, to a private business that now utilizes the bridge as a bungee jumping operation.  Crowds of people (often local fraternities/sororities doing team-building exercises) hang out on the old bridge all day and lean over the edge to watch their friends jump.  The company has bolted a frame and winch to the bridge deck to facilitate the bungee operation.

I would contend that the bungee jumping represents a new use, and that the bridge went from something not even regulated by the building code to becoming an Assembly Group A-5 "Amusement Park Structure".

I wonder if Weston's project would be classified similar to the Grand Canyon Skywalk bridge?


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## ADAguy (Sep 19, 2018)

Good points for consideration.
As only a "hike-in" I take it it is not accessible?


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## mark handler (Sep 19, 2018)

*I would classify it an accessory deck, to the building classification. A or B*


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## cda (Sep 19, 2018)

https://ixquick-proxy.com/do/spg/sh.../7288.jpg&sp=7053b5c208bbe40a0eb618bb69002ece


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## mark handler (Sep 19, 2018)

cda said:


> https://ixquick-proxy.com/do/spg/show_picture.pl?l=english&rais=1&oiu=https://www.fema.gov/media-library-data/7db58472-90ab-40f9-bc76-ed3ff3a44181/7288.jpg&sp=7053b5c208bbe40a0eb618bb69002ece


Okay, and why the drone pic?
And how does it relate to the tower classification?


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## cda (Sep 19, 2018)

In case someone wanted to visit and see the tower 


Plus did not know what the place looked like


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## mark handler (Sep 19, 2018)

cda said:


> In case someone wanted to visit and see the tower
> 
> 
> Plus did not know what the place looked like


And where is the tower, they have not yet built


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## cda (Sep 19, 2018)

Oops 

Maybe we can pick out a location


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## Weston (Sep 19, 2018)

Thank you all for the information and sorry for not providing enough information and at a faster rate. There will be a flight of spiral stairs that lead you up to the observation deck - the actual deck will be a semi-circle with a diameter of 20' where it will have roughly 110 sf of standing room. The Observation tower will have a floor-floor height of 24'-2" with guard rails on the floor of the deck.  Construction will be CIP concrete.


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## Weston (Sep 19, 2018)




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## Weston (Sep 19, 2018)




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## cda (Sep 19, 2018)

I like 

“ U “


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## cda (Sep 20, 2018)

Weston, your pictures disappeared ?????


If you can make it into a link, that should work


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## ADAguy (Sep 20, 2018)

OMG, what about access for the disabled tourists, they don't count or are you providing alternate means, some type of at grade video?


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## Builder Bob (Sep 24, 2018)

U with bungee slingshot for ada accessibility?


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## mark handler (Sep 24, 2018)




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## ADAguy (Sep 24, 2018)

ADAguy said:


> OMG, what about access for the disabled tourists, they don't count or are you providing alternate means, some type of at grade video?


*Still waiting for a response*


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