Fire separation b/w adjoining buildings with joint service doorways

[classicT]

2015 I-Codes w/ Washington Amendments
Type VB Construction
Two buildings, 3149sf and 2472sf
Non-sprinklered

Proposal is to maintain separation of two existing buildings with 0-ft setback from property lines by installing 90-min rolling fire doors at the (2) proposed doorways to be opened between the existing buildings. Intent is to prevent the use of fire sprinklers by keeping fire area to less than 5000sf (sprinklers are non-feasible due to service capabilities).

Below is the submitted detail for the jamb at the rolling fire door. Please note that the 8-inch CMU wall is the proposed 2-hr firewall. Questions are as follows:

1) Per IBC Section 706.1.1, any wall located on a lot line between adjacent buildings, which is used or adapted for joint service between the tow buildings, shall be constructed as a fire wall...(all good so far)... Party walls shall be constructed without openings and shall create separate buildings. Exception: Openings in a party wall separating an anchor building and a mall shall be in accordance with Section 402.4.2.2.1.

Do you agree that this does not apply, as the existing walls are each approximately 1-inch from the property line?

2) As the 8-inch CMU wall is the proposed means to meet the requirements for the 2-hr fire wall, should the rolling fire door be installed flush to the CMU wall? As shown in the detail, if a fire were to occur on the rear face of the door (brick wall side, bottom side of figure), the fire separation is made by the mounting hardware and the rated door is offset approximately 4-inches from the rated wall.

Thanks in advance for any pearls of wisdom.

 

[RLGA]

Since they are two separate walls located within the lot lines of each respective building, they are considered exterior walls and not fire walls (or even a party wall). Thus, as exterior walls, Table 705.8 does not allow openings for exterior walls within 3 feet of a lot line.

 

[classicT]

Since they are two separate walls located within the lot lines of each respective building, they are considered exterior walls and not fire walls (or even a party wall). Thus, as exterior walls, Table 705.8 does not allow openings for exterior walls within 3 feet of a lot line.

If properties are condensed to form one lot (thus no lot line b/w), then would you treat this as a fire wall for purposes of reducing the fire area to less than 5000sf, thereby exempting sprinklers?


FYI, intent is something similar to below (image taken from Overhead Door brochure).

 

[RLGA]

If the properties are combined to form a single lot, then the buildings can be connected either as one building (if height and area permits) or as double fire walls. However, you'll need doors in both walls--not just the one. The reason for this is that should the building with the door collapse, it would leave the opening in the other building unprotected, and the purpose of a fire wall and any door assemblies within the fire wall are to remain intact should the building on either side collapse.

 

[classicT]

If the properties are combined to form a single lot, then the buildings can be connected either as one building (if height and area permits) or as double fire walls. However, you'll need doors in both walls--not just the one. The reason for this is that should the building with the door collapse, it would leave the opening in the other building unprotected, and the purpose of a fire wall and any door assemblies within the fire wall are to remain intact should the building on either side collapse.

Agreed, thank you. Was not sitting well, and this was the reminder that I needed.

 

[RLGA]

Now, that being said, should the lots be combined, there is another solution for the double fire wall that would eliminate having double doors. It is not specifically addressed in the code or even NFPA 221, Standard for High Challenge Fire Walls, Fire Walls, and Fire Barrier Walls, but I have done this in the City of Phoenix and it was accepted. The door can be a single fire door supported by a structural frame that is independent of each wall and has its own footings. The joints between the frame and the two walls are protected using a joint firestopping system.

 

[classicT]

Now, that being said, should the lots be combined, there is another solution for the double fire wall that would eliminate having double doors. It is not specifically addressed in the code or even NFPA 221, Standard for High Challenge Fire Walls, Fire Walls, and Fire Barrier Walls, but I have done this in the City of Phoenix and it was accepted. The door can be a single fire door supported by a structural frame that is independent of each wall and has its own footings. The joints between the frame and the two walls are protected using a joint firestopping system.

Ron, do you also agree that the 90-min separation is not maintained at the track installed for the door? The door being installed approximately 4-inches from the rated wall leads me to question how protection is maintained at the edge of the proposed door.

 

[RLGA]

Ron, do you also agree that the 90-min separation is not maintained at the track installed for the door? The door being installed approximately 4-inches from the rated wall leads me to question how protection is maintained at the edge of the proposed door.

It is hard to say. What are the details for the tested fire door assembly? If they match with what is shown on the drawings, then I would say that the door provides the required protection.

 

[ADAguy]

Always be "wary" of manufacturers photos, inquire as to where and how it was accepted.

 

[steveray]

It is hard to say. What are the details for the tested fire door assembly? If they match with what is shown on the drawings, then I would say that the door provides the required protection.

Exactly...some fire dampers are allowed to be out of plane, but it is a function of the listing of the device....