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Something not right..................

JPohling

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I am away from my desk and code materials, but I was just advised by the buildings architect that we will need to provide a 90 minute fire rated fire shutter to protect a bank tenant from a ground floor high rise building lobby. This is a Type 1-A fully fire sprinkled high rise building located in Los Angeles. So 2019 CBC.

This is in response to the bank downsizing and in turn increasing the ground floor building lobby. I have attached a couple plans. The demo plan shows the existing conditions. Note the non rated storefront glass and double doors that separate the existing bank from the existing elevator lobby. The floor plan shows the condition after the bank has pulled back to the new demise creating a true ground floor lobby for the building. This lobby is two floors tall, and the elevator lobby on the second floor overlooks the lobby area.

This condition is replicated in every jurisdiction I have worked in. Typically the ground floor tenants fronting the lobby have full height glass that is in no way protected.

Unlimited area building. non separated occupancies can easily be achieved. I for the life of my cannot figure out what is making the building architect impose this requirement.

Can anyone think of a code requirement that would require this? Thanks for your time.
 

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e hilton

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Tell the architect to put down the pencil and go walk through a couple of high rise buildings.
 

cda

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I am away from my desk and code materials, but I was just advised by the buildings architect that we will need to provide a 90 minute fire rated fire shutter to protect a bank tenant from a ground floor high rise building lobby. This is a Type 1-A fully fire sprinkled high rise building located in Los Angeles. So 2019 CBC.

This is in response to the bank downsizing and in turn increasing the ground floor building lobby. I have attached a couple plans. The demo plan shows the existing conditions. Note the non rated storefront glass and double doors that separate the existing bank from the existing elevator lobby. The floor plan shows the condition after the bank has pulled back to the new demise creating a true ground floor lobby for the building. This lobby is two floors tall, and the elevator lobby on the second floor overlooks the lobby area.

This condition is replicated in every jurisdiction I have worked in. Typically the ground floor tenants fronting the lobby have full height glass that is in no way protected.

Unlimited area building. non separated occupancies can easily be achieved. I for the life of my cannot figure out what is making the building architect impose this requirement.

Can anyone think of a code requirement that would require this? Thanks for your time.


Is this an atrium area?? Or creating one??

Not sure where 90 minutes would come from, odd number
 

hapyhour

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Santa Clara
Agree, sounds like an atrium. see table 716.1. a 2 hour wall assembly requires a 90 min fire door.
 

ADAguy

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Sep 11, 2013
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! open to 2nd floor elevator lobby is the issue. Had this same situation back in the 70's, had to provide rolldown doors in the event of a fire.
 

classicT

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Oh that question was asked, along with the appropriate code sections. Not an Atrium. Just a tall lobby open to the elevator lobby on the second floor.
Why is it not an atrium?

This lobby is two floors tall, and the elevator lobby on the second floor overlooks the lobby area.

Below is the definition of an atrium. Not sure how you do not fall under this definition.

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.
 

classicT

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Per my last post, I believe that the "lobby" constitutes an atrium, and is therefore subject to the special detailed requirements of Ch. 4.

404.6 Enclosure of Atriums
Atrium spaces shall be separated from adjacent spaces by a 1-hour fire barrier constructed in accordance with Section 707 or a horizontal assembly constructed in accordance with Section 711, or both.
Exceptions:

  1. A fire barrier is not required where a glass wall forming a smoke partition is provided. The glass wall shall comply with all of the following:
    1. Automatic sprinklers are provided along both sides of the separation wall and doors, or on the room side only if there is not a walkway on the atrium side. The sprinklers shall be located between 4 inches and 12 inches (102 mm and 305 mm) away from the glass and at intervals along the glass not greater than 6 feet (1829 mm). The sprinkler system shall be designed so that the entire surface of the glass is wet upon activation of the sprinkler system without obstruction;
    2. The glass wall shall be installed in a gasketed frame in a manner that the framing system deflects without breaking (loading) the glass before the sprinkler system operates; and
    3. Where glass doors are provided in the glass wall, they shall be either self-closing or automatic-closing.
  2. A fire barrier is not required where a glass-block wall assembly complying with Section 2110 and having a 3/4-hour fire protection rating is provided.
  3. A fire barrier is not required between the atrium and the adjoining spaces of any three floors of the atrium provided such spaces are accounted for in the design of the smoke control system.
Per 404.6, a 1-hr fire barrier is required to provide separation between the atrium and the adjacent bank space. Note that any of the (3) exceptions may be applied, the first being most likely the most conducive to your specific situation.

Also want to point out that the opening protective would only need to be 45-min, not 90-min. The fire barrier is only 1-hr; therefore, per Table 716.5 (Other Fire Barriers), the opening protective (fire shutter assembly) is 3/4-hr.
 

Sifu

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Sep 3, 2011
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1,368
Agree with Ty. You state the existing conditions you see are full height glass that are in no way protected. FWIW, I have seen existing installations that use sprinklers to wash the glass that have been accepted as an alternate to a 1-hr wall. Is it possible that is the existing condition? Doesn't explain the 90-min requirement but may help reconcile the general conditions.
 

JPohling

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Why is it not an atrium?



Below is the definition of an atrium. Not sure how you do not fall under this definition.

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.
Ty, I am still awaiting documents from the architect. The rendering depicted a two story volume lobby where the elevator lobby on the 2nd floor was open to the ground floor lobby. It appeared to have separation of the 2nd floor elevator lobby from the rest of the 2nd floor space, so essentially only the hoistway on the 2nd floor is open to the ground floor lobby. I did not interpret that to be an Atrium. I really need to see what they are proposing.
 

JPohling

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Yes... but if an atrium, still must comply with 404.6. Exception #3 works.
If the only thing open to the lobby are the 1st and 2nd floor hoistways and elevators then I do not believe it is an Atrium.

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.
 

classicT

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If the only thing open to the lobby are the 1st and 2nd floor hoistways and elevators then I do not believe it is an Atrium.

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.
Note that per the atrium definition the stairways, elevators, hoistways, etc. must be enclosed. Plus it says elevator, not elevator lobby; the lobby is part of the 2nd floor. Per your OP, "...the elevator lobby on the second floor overlooks the lobby area." So the atrium connects the main level to the 2nd level elevator lobby, which in turn is separated from the remainder of the 2nd floor.

Separating the 2nd level elevator lobby from the remainder of the 2nd floor is required, as atrium spaces shall be separated from adjacent spaces by a 1-hour fire barrier constructed in accordance Section 404.6 (which I previously posted).

So to me, it sounds like the building was constructed in a means that treated the 2-story area as an atrium. This is given the separation noted at the 2nd level, plus the understanding that the existing bank probably complies with Section 404.6, Exemption #1 (glass wall with deluge sprinklers).
 
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