510.4 Parking Beneath Group R

[Ryan Schultz]

In order to take advantage of the following, does the garage need to be above grade? Or can it be a below grade garage? The wording is slightly confusing to me.

https://up.codes/viewer/wyoming/ibc-2015/chapter/5/general-building-heights-and-areas#510.4

510.4 Parking Beneath Group R

Where a maximum one story above grade plane Group S-2 parking garage, enclosed or open, or combination thereof, of Type I construction or open of Type IV construction, with grade entrance, is provided under a building of Group R, the number of stories to be used in determining the minimum type of construction shall be measured from the floor above such a parking area. The floor assembly between the parking garage and the Group R above shall comply with the type of construction required for the parking garage and shall also provide a fireresistance rating not less than the mixed occupancy separation required in Section 508.4.

 

[RLGA]

This section allows measuring building height in number of stories from the floor dividing the Group R and the Group S-2 parking. If the parking was entirely below grade, then there is no benefit from this section, since building height in stories would be determined using the grade plane just like any other building.

 

[Ryan Schultz]

I have a sprinkled 3 story type VB, R-2 occupancy above basement parking S-2.

The R-2 is maxed out area wise for a VB

The area of the S-2 basement parking is larger than the allowable sf footprint for a type vb.

So is the only approach in this scenario to use a 3hr horizontal seperation, and make the basement a type 1A?

 

[RLGA]

You could use Section 510.4 with a basement-only parking garage if the garage exceeds the allowable area for Type VB. This would only require a 2-hour separation per either Type I construction (either construction type can be used) for floor construction since Section 510.4 does not specify a higher fire-rating. You could also use Section 510.2, but that section requires a 3-hour horizontal separation and the classification for the lower building to be Type IA.

 

[Ryan Schultz]

Thank you kindly for the explanation.

I'm using 510.4 Parking Beneath Group R to realize a 2hr between the VB and the 1B.

 

[Ryan Schultz]

Whoops, meant to post that last comment over here: https://www.thebuildingcodeforum.co...-exterior-wall-roof-near-property-line.26922/

 

[J. Mulholland]

This section allows measuring building height in number of stories from the floor dividing the Group R and the Group S-2 parking. If the parking was entirely below grade, then there is no benefit from this section, since building height in stories would be determined using the grade plane just like any other building.

RLGA, is there ever a scenario in the code that does not require an S-2 open parking garage beneath Group R-2 (4-story apartments) above? We currently have a podium condition as outlined above. 2015 IBC

 

[J. Mulholland]

RLGA, is there ever a scenario in the code that does not require an S-2 open parking garage beneath Group R-2 (4-story apartments) above? We currently have a podium condition as outlined above. 2015 IBC

Sorry RLGA, my question was not clear. Is there ever a scenario in the code that does NOT require an S-2 open parking garage beneath Group R-2 (4-story apartments) above to be sprinklered?

 

[RLGA]

Sorry RLGA, my question was not clear. Is there ever a scenario in the code that does NOT require an S-2 open parking garage beneath Group R-2 (4-story apartments) above to be sprinklered?

No. Section 510.2, which would allow a Group S-2 occupancy below the horizontal separation, requires the Type IA construction to be sprinkled. Section 510.7 also allows open parking garages (non-Group S-2, but per Section 406.5) under a Group R. However, since there is no horizontal separation, buildings with a Group R occupancy are required to be sprinklered throughout; thus, the open parking garage would be required to be sprinklered.