Atrium "connection".

[Sifu]

IBC 404.5 requires smoke control as a base requirement. It then excepts atria that don't "connect" more than two stories. What is meant by connect? For example, If I have a 3 story atrium and none of the three stories are open to the atrium, is it connecting three (or any of the) stories? If not then no smoke control is required, but in order to be considered not connected do the elements that separate the atrium from the floors have to meet 404.6....this is where my mind starts to spin, because 404.6 exc. #4 is the directive that if no smoke control is required, then no separation is required.

The bottom line question is does a 3-story atrium require separation by 1-hr FB (or water washed glazing) if none of the floors are open to the atrium?

I really do not enjoy atriums.

 

[Paul Sweet]

Fire separation from the atrium used to be required, but 2018 IBC 404.6 exc. 4 waives this when a smoke control system isn't required.

Smoke control isn't required if there are no openings between the upper floors and the atrium.

 

[Sifu]

Fire separation from the atrium used to be required, but 2018 IBC 404.6 exc. 4 waives this when a smoke control system isn't required.

Smoke control isn't required if there are no openings between the upper floors and the atrium.

So this is the condition I am referring to. Say in the the 3 story atrium, none of the floors are open to the atrium anywhere. Then 404.5 would say smoke control is not required because no "connection" exists to the atrium, and none of the stories are connected to each other via the atrium. And if no smoke control is required then per 404.6 exc. #4 fire barriers are not required, but SOMETHING (but not a required 1-hr fire barrier or water washed glazing) has to provide a barrier to close off the connections to at least one of the stories, otherwise the connections exist for more than 2 stories and smoke control is required, hence fire barriers are required.

 

[Paul Sweet]

The last atrium I was involved with that extended through more than 2 stories was back in BOCA days. The building was fully sprinklered, the atrium was 4 stories high, open to the first & second stories, and separated by fire barriers and sprinkler-protected glass on the third & fourth stories. All the atriums I have been involved with since then only connected 2 stories.

I think that unrated partitions without operable doors or windows on one level (fixed glass is OK) would meet the new exception 4 for a 3 story atrium in a fully sprinklered building.