Interpretation #: CEB-2018-08-2014-IBC-406.6

Building or Fire Safety Law Interpreted

675 IAC 13-2.6, the 2014 Indiana Building Code, Section 406.6; Section 706; Table 706.4; Section 903.2.10; Section 903.2.10.1.

Interpretation of the State Building Commissioner

Section 406.6 Enclosed parking garages: This section is simply the scoping statement for all enclosed parking garages, stating that they are to comply with sections 406.6.1 through 406.6.3. No further interpretation of section 406.6 is required.

Section 706 FIRE WALLS: This section provides all of the requirements for fire walls in Class 1 structures, and includes the statement that any structure divided by fire walls constructed in compliance with the requirements of this section shall have those divisions considered separate buildings for the purposes of application of the code. There are subsequent subsections that describe minimum requirements for structural stability, combustibility of materials, minimum required fire-resistance ratings, horizontal and vertical continuity, special requirements for exterior walls, projecting horizontal elements, applications in stepped buildings and in buildings with sloped roofs, openings and penetrations, all of which must be met for the assembly to be considered a compliant fire wall. If interpretations are required for any of these subsections they must be requested specifically, as this interpretation is necessarily limited in scope, and it cannot be used for general explanations of entire code sections.

Table 706.4 FIRE WALL RESISTANCE RATINGS: This table provides the minimum fire-resistance ratings of construction that is needed for consideration as a compliant fire wall under this section, based on the occupancy group of the structure in question. Fire walls in S-2 occupancy group structures are shown in the table as having minimum fire-resistance ratings of 2 hours.

Section 903.2.10 Group S-2 enclosed parking garages: The section states that automatic fire suppression systems must be provided in any S-2 enclosed parking garage with a fire area that exceeds 12,000 square feet in size, or that is located beneath other occupancy groups (with the exception of R-3 occupancies). It also includes the following subsection 903.2.10.1, discussed below.

Section 903.2.10.1 Commercial parking garages: The section states that when an S-2 enclosed parking garage includes the storage of commercial trucks or buses, the maximum fire area limit of 903.2.10 is reduced from 12,000 square feet to 5,000 square feet.

General conclusions: The interested person is proposing to construct a 12,000 square foot S-2 parking structure used for the storage of commercial trucks. The interested person contends that the local building official has said that the structure must be divided into separate buildings in order to avoid the sprinkler requirement for a fire area larger than 5,000 square feet, and further, that construction of one or more compliant fire walls will not provide such division.

We do not know if this is an accurate assessment of the local official's position, but regardless, the position as described is incorrect. Not only will the use of fire walls compliant with the requirements of section 706 allow the structure to be considered separate buildings for the purposes of application of the code, that degree of separation is not necessary in order to meet the requirements of section 903.2.10.1. That section states that for S-2 utilized for storage of commercial trucks, the maximum allowable fire area for non-sprinklered construction is 5,000 square feet. It does not say the maximum building is 5,000 square feet. Separation of a structure into fire areas does not require the use of fire walls, but can be accomplished through the use of fire barriers compliant with section 707, including table 707.3.10. Fire walls are acceptable, but not necessary.

Having said that, it is important that all parties understand that there are other criteria that may require the structure to be sprinklered, even if it meets the fire area requirements of 903.2.10.1, specifically the "stories without openings" requirements of section 903.2.11.1 and its subsequent subsections 903.2.11.1.1 and 903.2.11.1.2, which must be met to avoid sprinklering as well.