Unprotected shed adjacent to a type III (A or B) Building

[mp25]

A business wants to install a wood or vinyl prefab shed 5' from an existing type III building. Due to the occupancy classification and area, the building cannot be reclassified to a construction type that does not require a fire resistance rated wall. The shed is used to store tables and chairs that are used for outdoor events.

Is there a code path to allow this installation, specifically an unprotected shed adjacent to a protected building? I could not find one except for a potential code modification using admin section of the IBC.

My first review I noted that the two separate structures can be considered as a part of one structure, and the shed would have to meet III-A/B construction OR these can be considered as two separate structures with an imaginary FSD between the two (503.1.2), which would also require some of the shed walls to be fire resistance rated. Thank you for the feedback.

2015 suite of codes, but if newer codes are more permissive in this regard, this is something I would consider in my code analysis. I hope I am overlooking something and there is an easy solution for this.

 

[Yankee Chronicler]

If you classify the shed as Type III-A or III-B, the exterior bearing walls have to be 2-hour rated, regardless of how close they are to the existing building. What's the distance between the two buildings? Does the existing building have any windows or doors facing the proposed location of the shed?

 

[mtlogcabin]

How big is the shed? What is the occupancy of the Type III building?

 

[mp25]

The shed is about 120 square feet. Occupancy class is A2. The buildings would be about 5 feet apart. No openings on the main building in the vicinity of the shed.

It feels somewhat excessive to request fire resistance rating for the shed, but that is the only code compliant path that I see. Does anyone else know of a code path to get to a point where this shed could be non-fire resistance rated or do you see it the same way that I do.

 

[Yankee Chronicler]

What's the fire resistance rating of the exterior wall of the existing building that will face the proposed shed? If type III construction it should be 2 hours -- is it? Or is it an u-rated non-bearing wall?

 

[Yankee Chronicler]

^^^ That should have been "unrated"

If you can set the fire separation line (the imaginary property line) at the face of the existing building (which is possible if it has a 2-hour rating), you can then site the proposed shed 5'-1" from it and make it construction type V-B. Table 705.5 will then only require that the wall facing the existing building have a 1-hour rating, which just means gypsum sheathing and a single layer of 5/8" firecode sheetrock on the inside face of that wall.