mezzanine in a type 1-A building

[georgia plans exam]

A mezzanine is being constructed on the ground floor of an existing 22 story type 1-A building. Does the mezzanine floor require a 2-hour rating?

GPE

 

[ADAguy]

Sprinklered building?
Within the space? If yes, then no as it is not a separation between floors.

 

[georgia plans exam]

That makes sense to me. Still, it is a floor and Table 601 seems to indicate a rating requirement...

GPE

 

[georgia plans exam]

Yes, sprinklered and within the space.

 

[RLGA]

In my opinion, it is an element that is part of the building and must, therefore, conform to the requirements of the building's construction type. The 2-hour floor construction is not required because of separation, but because of the need to protect the structural integrity of the mezzanine like any other element of the building.

 

[classicT]

Per Table 601, 2-hr rated floor is required. Ron put it best.

As to why, I am thinking a new footnote is needed. Code change proposal?

 

[georgia plans exam]

How about this - Table 601 requires 2-hour protection for floors. By definition, a mezzanine is not a floor, but an intermediate level between a floor and the structure above. Ron, would it make a difference if the mezzanine were not connected to the buildings primary structural frame?

GPE

 

[RLGA]

How about this - Table 601 requires 2-hour protection for floors. By definition, a mezzanine is not a floor, but an intermediate level between a floor and the structure above. Ron, would it make a difference if the mezzanine were not connected to the buildings primary structural frame?

GPE

By definition, a mezzanine is not a "story," but it is a floor--Table 601 does not mention that it only applies to floors between stories. Per Section 505.2, it specifically addresses the clear height of the "mezzanine floor construction." The floors of a mezzanine have to be designed like any other floor in the building per Chapter 16.

 

[classicT]

By definition, a mezzanine is not a "story," but it is a floor--Table 601 does not mention that it only applies to floors between stories. Per Section 505.2, it specifically addresses the clear height of the "mezzanine floor construction." The floors of a mezzanine have to be designed like any other floor in the building per Chapter 16.

I agree with Ron and his logic here.

 

[georgia plans exam]

Thank you all for the quick replies. GPE

 

[ADAguy]

Seems a grey area, if sprinklered wouldn't it be allowed to be of unrated construction and if not attached couldn't it be of a prefab steel construction as in a warehouse type?

 

[JPohling]

I have this exact same scenario. Proposed mezzanine within a tall first floor office area, B occupancy in a Type 1A building.
I too came to the conclusion that the 2 hour rated floor would be a requirement. How about the columns. 3 Hour rated? They are the primary structural frame for the mezzanine so I have concluded 3 HR required.

Does anyone have any alternative views? Our client would like an industrial looking steel column supported mezzanine, not one that has been wrapped in gyp or other assemblies to obtain fire ratings.

 

[ADAguy]

If need be the exposed steel could be coated with intumescant paint.

 

[RLGA]

If need be the exposed steel could be coated with intumescant paint.

Not intumescent "paint," but intumescent fireproofing. There is a difference. The paint version is not tested per ASTM E119 and is only used to improve the flame spread rating per ASTM E84.

 

[steveray]

I'm with Ron....If they wan't the "look" they could bury the steel and put in faux exposed steel beams just like is sometimes done with wood....

 

[ADAguy]

Not intumescent "paint," but intumescent fireproofing. There is a difference. The paint version is not tested per ASTM E119 and is only used to improve the flame spread rating per ASTM E84.

My "bad", that is what I meant (smiling).

 

[bkish444]

I have attached a code commentary reference that speaks directly to this.

 

[Yankee Chronicler]

Seems a grey area, if sprinklered wouldn't it be allowed to be of unrated construction and if not attached couldn't it be of a prefab steel construction as in a warehouse type?

Not a gray area at all. Type I construction -- floors (those things we walk on) must be 2-hour construction, per Table 601. There are no footnotes to allow a lower (or no) rating if the building is sprinklered.