stillfan
Structural
- Jan 18, 2010
- 35
We currently have a building that is classified as a construction type IIB, the client wants to change it to a IIIB because he has another structure sitting 5ft away that has a type IIIB classification. The code official told him to just make our building (IIB) a IIIB structure my question stems from the 2009 IBC code
Per section 602 Table 601 of the IBC 2009, a type IIIB construction type classification requires a 2 hr bearing wall fire rating(with foot note f & g) and a primary structural frame (with footnote g) of 0 hrs. See footnotes below:
f. Not less than the fire resistance rating based on fire separation distance (see Table 602)
• Table 602 reads a 1 hour fire resistance rating for all fire separation distances.
g. Not less than the fire resistance rating as referenced in section 704.10
Section 704.10 reads “ Exterior structural members. Load-bearing structural members located within the exterior walls or on the outside of a building or structure shall be provided with the highest fire – resistance rating as determined in accordance with the following:
1. As required by Table 601 for the type of building element based on the type of construction of the building
2. As required by Table 601 for exterior bearing walls based on the type of construction
3. As required by Table 602 for exterior walls based on fire separation distance.
The current interpretation of this code requirement as it applies to the fabric structure is as follows;
The tensioned fabric structure is supported by the primary structural frame, which per footnote g (noted above) must comply with 1 of 3 fire rating values , the highest of which will govern. The three scenarios are listed below:
1. 0 hrs
2. 2 hrs
3. 1 hr
The 2 hour fire rating is the highest value and determines that the Primary structural frame must adhere to a 2 hour fire rating in order to be code compliant. It is a concern of ours in that the fabric structure does not have a fire rating. It strictly adheres to the IIB compliance.
Please comment as to rather a 2 hour fire rating is needed since the IIB construction is non-combustable?
Per section 602 Table 601 of the IBC 2009, a type IIIB construction type classification requires a 2 hr bearing wall fire rating(with foot note f & g) and a primary structural frame (with footnote g) of 0 hrs. See footnotes below:
f. Not less than the fire resistance rating based on fire separation distance (see Table 602)
• Table 602 reads a 1 hour fire resistance rating for all fire separation distances.
g. Not less than the fire resistance rating as referenced in section 704.10
Section 704.10 reads “ Exterior structural members. Load-bearing structural members located within the exterior walls or on the outside of a building or structure shall be provided with the highest fire – resistance rating as determined in accordance with the following:
1. As required by Table 601 for the type of building element based on the type of construction of the building
2. As required by Table 601 for exterior bearing walls based on the type of construction
3. As required by Table 602 for exterior walls based on fire separation distance.
The current interpretation of this code requirement as it applies to the fabric structure is as follows;
The tensioned fabric structure is supported by the primary structural frame, which per footnote g (noted above) must comply with 1 of 3 fire rating values , the highest of which will govern. The three scenarios are listed below:
1. 0 hrs
2. 2 hrs
3. 1 hr
The 2 hour fire rating is the highest value and determines that the Primary structural frame must adhere to a 2 hour fire rating in order to be code compliant. It is a concern of ours in that the fabric structure does not have a fire rating. It strictly adheres to the IIB compliance.
Please comment as to rather a 2 hour fire rating is needed since the IIB construction is non-combustable?
