# Light Shaft is rating required?



## rdc022002 (Mar 23, 2021)

Hi everyone, not sure if there's a requirement per IBC 2018, specifically fire rating light shaft. Just to get another opinion if light shaft walls needs to be rated since it penetrates from roof to lower floor similar to figure shown below without vent louvers:






If  full glass or partial glass (part of the wall to be framed with gyp board) will be used an understanding if the glass needs to be rated or partial walls needs to be rated wall. We feel that it should be rated but we cannot find any code requirement to prove that it is required. Please let us know if you have any information.

Thanks!


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## cda (Mar 23, 2021)

Welcome to our humble forum.


Note:
Just because it has the word Fire, it can be in the IBC normally.


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## cda (Mar 23, 2021)

So is it all exterior wall,,, or part of the tenant space also??

What type occupancy??

How many floors total??

Do you have an atrium condition in the middle?


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## mtlogcabin (Mar 23, 2021)

Simple answer yes a shaft needs to be rated. How you accomplish that will depend on if it is a one hour or two requirement

[BF] SHAFT. An enclosed space extending through one or more stories of a building, connecting vertical openings in successive floors, or floors and roof.
713.4 Fire-resistance rating.
Shaft enclosures shall have a fire-resistance rating of not less than 2 hours where connecting four stories or more, and not less than 1 hour where connecting less than four stories. The number of stories connected by the shaft enclosure shall include any basements but not any mezzanines. Shaft enclosures shall have a fire-resistance rating not less than the floor assembly penetrated, but need not exceed 2 hours. Shaft enclosures shall meet the requirements of Section 703.2.1.

If it is not a shaft and can be classified as an atrium then there are options for protecting the glass in lieu of rated glazing see section 404 IBC

[BG] ATRIUM. An opening connecting two or more stories other than enclosed stairways, elevators, hoistways, escalators, plumbing, electrical, air-conditioning or other equipment, which is closed at the top and not defined as a mall. Stories, as used in this definition, do not include balconies within assembly groups or mezzanines that comply with Section 505.


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## rdc022002 (Mar 23, 2021)

cda said:


> So is it all exterior wall,,, or part of the tenant space also??
> 
> What type occupancy??
> 
> ...


It's all interior all light shaft measure 4'-0"x4'-0" in a fire suppressed space, 4 floors, occupancy B, no atrium condition. Application is similar to a light tube in residential application.


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## rdc022002 (Mar 23, 2021)

mtlogcabin said:


> Simple answer yes a shaft needs to be rated. How you accomplish that will depend on if it is a one hour or two requirement
> 
> [BF] SHAFT. An enclosed space extending through one or more stories of a building, connecting vertical openings in successive floors, or floors and roof.
> 713.4 Fire-resistance rating.
> ...


The argument was that there was nothing pertaining specifically to light shaft. In IBC 2015 a light tube was categorized as a window. It is a skylight in theory 4'x4' in dimension. Thanks!


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## RLGA (Mar 23, 2021)

Since it penetrates multiple stories, it is a shaft by definition and is subject to the fire-resistance ratings specified in Section 713 (2018 IBC).


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## rdc022002 (Mar 23, 2021)

RLGA said:


> Since it penetrates multiple stories, it is a shaft by definition and is subject to the fire-resistance ratings specified in Section 713 (2018 IBC).


Agree, thanks!


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## cda (Mar 23, 2021)

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## cda (Mar 23, 2021)

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