Is a Mezzanine considered a "floor"?

[Tim Mailloux]

The first floor area of the warehouse communicates atmospherically with the addition (mezzanine) at the first floor and someone was smart enough, I believe, to put basically an atrium of sorts (I would call it floor openings as an example escalator openings from one level to the next) so that the other two levels communicate atmospherically as well. On that, I had plenty of comments concerning the mechanical systems, but that is another problem.

Without seeing plans and a building section Im not sure those upper (2) levels would meet the requirements of a mezzanine

 

[Blazer]

I think I am not laying this out correctly. I still can't upload any pics or links without a url link, sorry.
So lets say you have 100,000 sq. ft. warehouse single story unlimited building and they are proposing to build an addition of what consists of 3 stories above grade. the designer is proposing to build the addition as an extension of the warehouse by attaching it to the warehouse.
One thing is apparent, can't be 3 stories with unlimited construction, hence the mezzanine approach.
So they want to knock out the 1st floor wall to communicate with the 3 story mezzanine (I think it is a 3 story addition) and by being a 1/3 of the total floor area of the warehouse doable. I guess my question rests on the interpretation of where does the mezzanines intermediate levels within the floor to ceiling truly begin? If by reading the definitions, I would think this has to be inside of the warehouse, not in a 3 story addition. Though by knocking out the first floor wall of the warehouse and communicating with the addition (mezzanine)on the first floor and a floor openings to the 2nd & 3rd levels, I don't see how that is compliant. And the fact that that have a full blown commerical kitchen for employees on the third floor (intermediate level) makes it more nonsensical to me. how do others see it.

So 1 story warehouse, proposing a mezzanine in the form of a 3 story addition with the first floor opening directly (communicating)with the first floor directly and lets call it a mini atrium, though I tend to think floor openings like in an escalator setup 12 ft. by 12 ft. going up thru the second level and third level with a skylight to cap it off. Definitely communicating in more than one way, but for sake staying on topic, the mezzanine (addition) is now communicating with the ware house. So the question is, is this mezzanine compliant by definition of being within the floor ceiling of the warehouse.

Sorry no specific code references, at home recovering from the mental meat grinder at work this past week, but the main sections IBC/VCC 505 and 507, 508 chapters for a reference.
I think it can not qualify as a mezzanine because it is not inside of the main building where the language seems to indicate. As an example and one of the exceptions where special industry complex's can have mezzanines up to 2/3 of the total area, think a smelting plant with mezzanines at intermediate levels within, the plant could be one story up 75 in height and have all this (floor areas) mezzanines inside from floor to ceiling...

Thanks

Mezzanine can only be 1/3 of the "open" floor area. I guess if it is a warehouse with no enclosed spaces you can be 1/3 the total floor area.
You can have one story with really tall ceilings. It just so happens the ceiling is so tall you can put 2 levels of mezzanine (at least 7ft clear space). As long as 'aggregate area of a mezzanine or mezzanines within a room shall be not greater than 1/3 the floor area'

 

[TheCommish]

Mezzanine can only be 1/3 of the "open" floor area. I guess if it is a warehouse with no enclosed spaces you can be 1/3 the total floor area.

Follow on questions, if Ihave a 75,000 sf. warehouse 36 feet tall and build a big cooler floor to ceiling say 5000 sq feet, this is now 70,000 sf. so the mezzanine can only be 23,100 sf. Next, a room is proposed that takes up an additional 10,000 sf. how is the existing mezzanine handled that is now too big?

next question, assuming or building is 75,000 less the 5000 sf. cooler, and a room is built that is 10,000 sf. floor to ceiling, can I put a mezzanine in that room? If so do you calculate the mezzanine sizes based on the room the deduct that area from the building's overall mezzanine allowed area?

 

[Tim Mailloux]

Are all three levels of the mezzanine open to the warehouse? Based on one of the descriptions in a previous post i understood that only the lower level of the mezzanine was open to the warhouse, and the 2nd and 2rd levels of the mezzanine were open to the 1st mezzanine level with a sort of atrium. If thats the case im not sure the upper mezzanine levels would qualify as mezzanines.

 

[Bryant]

Are all three levels of the mezzanine open to the warehouse? Based on one of the descriptions in a previous post i understood that only the lower level of the mezzanine was open to the warhouse, and the 2nd and 2rd levels of the mezzanine were open to the 1st mezzanine level with a sort of atrium. If thats the case im not sure the upper mezzanine levels would qualify as mezzanines.

That's it! my thinking as well. There is a difference between level and story and when looking at this project, it is a 3 story addition on an unlimited area building of which is maxed out at 2 stories. Its one thing to extend the unlimited area, or if even to put an accessory structure (in this case a 3 story addition) to the main use. We can get into all the percentages of allowable area based on the aggregate area in play, but in my opinion the mezzanine is defined by definition as levels with in a story, not three stories in a mezzanine. Some would conclude by having a 12 x 12 hole in the floor (not unlike a thru floor opening for an escalator for example) to constitute the openness to the first floor as a continuation of. I don't think that is the intent. Anyway my supervisor is going to take it over, since I can not honestly say it meets the definition of a mezzanine as proposed as a 3 story addition.
I probably should have put up a poll laying out the argument for and against to see where the chips fall....

 

[Tim Mailloux]

this is some of the code commentary to section 505.2.1, based on this commentary I am of the opinion that you can have multiple mezzanine levels as long as each mezzanine level is atmospherically open to the room or space the mezzanine is part of. The atrium condition you describe would not qualify IMO...

So as not to contribute significantly to a building’s inherent fire hazard, a mezzanine is restricted to a maximum of one-third of the area of the room with which it shares a common atmosphere. The area may consist of multiple mezzanines open to the same room at the same or different levels, provided that the aggregate area does not exceed the one-third limitation (this determination is based on the gross floor area of the mezzanines). If the area limitation is exceeded, the provisions of this section do not apply, the mezzanine level is considered an additional story and the area of the mezzanine would be included in building area.

 

[MHGuru]

That is a good analogy of use. I can see that as a multi tiered building with mezzanines at intermediate levels. Still the mezzanine levels are inside the building from floor to ceiling within that building. My problem is they are trying to have a one story building addition (the mezzanine piece) attached to the remaining warehouse, using the aggregate floor area of the warehouse to extract a 1/3 ratio for the mezzanine(s) in this case a three story building equally divided. The first floor area of the warehouse communicates atmospherically with the addition (mezzanine) at the first floor and someone was smart enough, I believe, to put basically an atrium of sorts (I would call it floor openings as an example escalator openings from one level to the next) so that the other two levels communicate atmospherically as well. On that, I had plenty of comments concerning the mechanical systems, but that is another problem.
Anyway need to think more on this. I may be approaching this from the wrong angle, in that considering the most restrictive requirements for the use, which could include separating areas (fire areas) rated assembly between and so on.

I have an unlimited area building F1, S1, B existing 100,000. sq. ft.
proposed mezzanine addition 33,000 sq. ft. 3 levels, 1st & 2nd business ( B), 3rd (A2) is totality a commercial kitchen for employees, cafeteria, dining lounge with computer lounge and ping pong table to boot and an outdoor patio, nice setup for a 3rd level mezzanine inside of a 3 story addition.
All of this attached to the warehouse, with out exceeding the height and area for a IIB construction fully sprinklered building.

I am missing a point of view backed up code, that is my dilemma, hence reaching out for advice.
Unfortunately, many other projects that need equally undivided attention as well, time sensitive. I guess I'll save this one for bar talk gossip at the next code update training
Thanks

That's it! my thinking as well. There is a difference between level and story and when looking at this project, it is a 3 story addition on an unlimited area building of which is maxed out at 2 stories. Its one thing to extend the unlimited area, or if even to put an accessory structure (in this case a 3 story addition) to the main use. We can get into all the percentages of allowable area based on the aggregate area in play, but in my opinion the mezzanine is defined by definition as levels with in a story, not three stories in a mezzanine. Some would conclude by having a 12 x 12 hole in the floor (not unlike a thru floor opening for an escalator for example) to constitute the openness to the first floor as a continuation of. I don't think that is the intent. Anyway my supervisor is going to take it over, since I can not honestly say it meets the definition of a mezzanine as proposed as a 3 story addition.
I probably should have put up a poll laying out the argument for and against to see where the chips fall....

 

[MHGuru]

Yes indeed. That is why they proposed removing the wall at grade level in order to communicate "atmospherically" with the mezzanine (addition) to the existing warehouse space. The question always comes back to is it inside of warehouse from floor to ceiling or outside of. The addition/mezzanine in my opinion is outside of, but you could argue for an extension of the existing building and since they call it a mezzanine, escape calling it a 3 story addition of which could not be part of an unlimited building and would in my opinion again. create another fire area and thus a fire resistance rating at that point of connection. This is where my troubles begin, what is it....
Thanks

This is an awesome subject. I have been doing research all day and came across this case study you may find interesting. Check it out, hope it helps. https://www.peaklogix.com/portfolio/increased-facility-capacity/

 

[Bryant]

This is an awesome subject. I have been doing research all day and came across this case study you may find interesting. Check it out, hope it helps. https://www.peaklogix.com/portfolio/increased-facility-capacity/

This is a case of the classic mezzanine, a level within the story. Could be several levels pending the allowable height of the existing structure. My example is a little more involved, and as outlined in the posts, is a 3 story addition, not a level(s) within a story. The long story short, they wanted to knock out the wall at the first story and extend out the footprint of the original building in order to create a mezzanine. with a 12 x 12 thru floor penetration going up to the skylight thru the 2nd & 3rd floors..
That dog won't hunt IMHO, simply because of definition for one, and secondly 3 story addition when the original building is an unlimited area building maxed out at 2 stories, even though they stay under the max building height for a unlimited area building.

 

[ADAguy]

"very" interesting

 

[Bryant]

"very" interesting

how so? My supervisor is doing the project now, so no skin in the game. She said, he said is kinda what the consensus is. I didn't agree based on all the relevant code data, what is proposed and how they got there thru the code. Guess that's why I'm off the review . Never seen a mezzanine disguised as a 3 story addition before. I am all ears for anybody to opine on....

 

[Mr. Inspector]

Had a existing building where they wanted to build a mezzanine that took 1/2 of the room it was in. The building would have needed sprinklers if 2 story. So they took a door off so the room that the mezzanine is in extended into the next room to make it one larger room. Now the mezzanine is less than 1/3 of this larger room.
I don't understand how this makes things safer. Could someone explain?

 

[steveray]

Had a existing building where they wanted to build a mezzanine that took 1/2 of the room it was in. The building would have needed sprinklers if 2 story. So they took a door off so the room that the mezzanine is in extended into the next room to make it one larger room. Now the mezzanine is less than 1/3 of this larger room.
I don't understand how this makes things safer. Could someone explain?

Not sure that I would call taking the door off "openness"....But there are alot of exceptions....

505.2.3 Openness. A mezzanine shall be open and unobstructed
to the room in which such mezzanine is located
except for walls not more than 42 inches (1067 mm) in
height, columns and posts.

 

[Mr. Inspector]

Here was another way a too large of a mezzanine was fixed by making an opening a mezzanine wall into a different room:

Small mezzanine in even smaller room in a small building.

2009 IBC. Barn being converted to club house for gulf course with restaurant (A2)and pro shop (M). 5B construction 2050 sq ft., no sprinklers, all one fire area so A2 use with a mezzanine. Sprinklers are required if 5,000 sq. ft. or 2 floors. Pro shop has a door between it and the restaurant...

www.thebuildingcodeforum.com

I still don't understand why by doing this to avoid sprinklers makes it safer. Maybe someone could tell me?

 

[steveray]

Because when it is "one room or atmosphere" you are more likely to know there is a problem and get out....Just like a fire alarm, earlier notification = safer...

 

[ADAguy]

Isn't a room enclosed vs a mezzanine opening into it unenclosed?
Removal of a door to the room does not result in the room no longer being called a room, or does it?

 

[Mr. Inspector]

Removal of a door to the room does not result in the room no longer being called a room, or does it?

The code says room or space with no definition of either.

Because when it is "one room or atmosphere" you are more likely to know there is a problem and get out....Just like a fire alarm, earlier notification = safer...

But is still one room if the mezzanine is half the size of the room it is in rather than just a third.
I wonder if there were any studies and testing on this or it was just made up.

 

[Bryant]

Had a existing building where they wanted to build a mezzanine that took 1/2 of the room it was in. The building would have needed sprinklers if 2 story. So they took a door off so the room that the mezzanine is in extended into the next room to make it one larger room. Now the mezzanine is less than 1/3 of this larger room.
I don't understand how this makes things safer. Could someone explain?

IMHO, there is a loophole in how one could quantify a mezzanine (definition wise) when veiled as an addition. If you read my post from the beginning you will see a 3 story addition trying to quantify as a mezzanine in an unlimited area building of which can not be more than 2 stories. knocking out the first floor wall and using in my mind a floor thru penetration like for an escalator and call it a day with 3 levels on the addition? Anyway, I'm not on that project anymore. Sometimes you have to stand your ground and let the BO make the call, absent my approval of course

 

[Bryant]

IMHO, there is a loophole in how one could quantify a mezzanine (definition wise) when veiled as an addition. If you read my post from the beginning you will see a 3 story addition trying to quantify as a mezzanine in an unlimited area building of which can not be more than 2 stories. knocking out the first floor wall and using in my mind a floor thru penetration like for an escalator and call it a day with 3 levels on the addition? Anyway, I'm not on that project anymore. Sometimes you have to stand your ground and let the BO make the call, absent my approval of course

meant to say by definition, story Vs. level......

 

[Tim Mailloux]

based on the definition of openness (which SteveRay) posted several posts back I don't see the (3) story addition you describe as meeting the intent of a mezzanine.

505.2.3 Openness. A mezzanine shall be open and unobstructed
to the room in which such mezzanine is located
except for walls not more than 42 inches (1067 mm) in
height, columns and posts.