Exiting from one use group through an...

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Author Message Russ Hinkle, AIA, CDT, LEED BD+C Senior Member Username: rhinkle Post Number: 111 Registered: 02-2006 Posted on Wednesday, February 06, 2013 - 05:01 pm:    We are discussing code issues with the state official and a comment has come up that we need to address. "Can the Health Care Occupancy (I-2) exit through the Business Occupancy lobby?" The building is multistory (not highrise) with I-2 on 2 thru 4 and Business on the first floor. The entire building is constructed using the more strigent I-2 requirements (2 hr protected structure, etc.) Is there something specific in the code about this that we are missing? Russ Hinkle Nathan Woods, CSI, CCCA, LEED AP Senior Member Username: nwoods Post Number: 507 Registered: 08-2005 Posted on Wednesday, February 06, 2013 - 05:10 pm:    Yes you can, as long as you maintain the rating all the way through. Nathan Woods, CSI, CCCA, LEED AP Senior Member Username: nwoods Post Number: 508 Registered: 08-2005 Posted on Wednesday, February 06, 2013 - 05:12 pm:    Actually, let me clarify my answer. You need to provide an Occupancy Separation between the B and the I. So your exit may extend between them and into the B occupancy exit lobby, but the rating for the I (2 hour) must be maintained, and you need fire separation between the two occupancies. This can just be fire doors on hold-opens and you're good to go. Double check that the lobby is 2 hour rated, as that's rare in a B. Steven Bruneel, AIA, CSI-CDT, LEED-AP, EDAC Senior Member Username: redseca2 Post Number: 382 Registered: 12-2006 Posted on Wednesday, February 06, 2013 - 05:23 pm:    I agree with Nathan. Also, if the exit path from the lobby continues outside under an entry canopy, that will need to be of the same fire resistive construction. So if you have exposed structure, what you save on giving up the AESS you will spend on exterior intumescent fireproofing. Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP Senior Member Username: specman Post Number: 1085 Registered: 03-2003 Posted on Wednesday, February 06, 2013 - 05:48 pm:    Short answer is yes. Per Section 1027 (2012 IBC), the exit discharge from an interior exit stairway may egress through areas on the level of exit discharge. However, only 50% of the number and capacity can do so. In other words, if you are required to have three exit stairways (occupant load over 500), then only one stairway may egress as such (two stairways would be more than 50% of the number). Also, assuming the total capacity of all three exits is 660 occupants, then the maximum capacity of the stairway egressing through the lobby would be limited to 330 occupants (50% of the capacity). There are other requirements for the exception: 1. Must provide a free and unobstructed path to an exterior exit door. 2. The level of exit discharge must be separated from any levels below by construction equal to the stairway exit enclosure. 3. The path from the stairway to the exterior exit door and all areas with access to the pathway must be protected by a sprinkler system or be separated from the pathway by construction equal to the stairway exit enclosure. Ron Geren, AIA, CSI, CCS, CCCA, SCIP www.specsandcodes.com Russ Hinkle, AIA, CDT, LEED BD+C Senior Member Username: rhinkle Post Number: 112 Registered: 02-2006 Posted on Thursday, February 07, 2013 - 10:01 am:    Nathan - there is a two hour seperation between the first floor and second floor. The two hour stair enclosure extends down in to the business use 1st floor. The pathway from the stair door to the exterior doors (there are actually two choices)meets the exceptions Ron states (sprinklers, there is no level below). I am not getting why the lobby would need a two hour seperation? Russ Hinkle Nathan Woods, CSI, CCCA, LEED AP Senior Member Username: nwoods Post Number: 511 Registered: 08-2005 Posted on Thursday, February 07, 2013 - 10:56 am:    Russ, sorry I am commuting a lot this week and don't have a code book in front of me, but the key premise to my comment is that you cannot reduce the rating. If you are exiting your I-2.1 through a 2 hour separation, you need to maintain that all the way out the building, thus the protected lobby. Perhaps there is an exception that allows otherwise, this is the basic concept. Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP Senior Member Username: specman Post Number: 1086 Registered: 03-2003 Posted on Thursday, February 07, 2013 - 11:18 am:    The lobby only needs to be separated if the adjoining spaces are not protected by a sprinkler system. If the entire floor is protected by a sprinkler system, then no separation is required. Ron Geren, AIA, CSI, CCS, CCCA, SCIP www.specsandcodes.com Russ Hinkle, AIA, CDT, LEED BD+C Senior Member Username: rhinkle Post Number: 113 Registered: 02-2006 Posted on Thursday, February 07, 2013 - 01:36 pm:    Thanks for the feedback, it helps confirm that what we thought we knew. Second question - Can a fire barrier be horizontal (as in a rated floor system). The definition of a "fire barrier" does not seem limit it vertical walls, however all the code references seem to imply that a fire barrier is a vertical wall dividing up floor area on a particular floor. Russ Hinkle Nathan Woods, CSI, CCCA, LEED AP Senior Member Username: nwoods Post Number: 512 Registered: 08-2005 Posted on Thursday, February 07, 2013 - 02:12 pm:    Yes, your floor/ceiling assembly can and and should be a 2 hour separation if it divides a B and I occupancy. The trick here is that all your penetrations and your edge of deck/wall framing details need a 2 hour F and T rating. F ratings are easy, the T ratings typically require an Engineering Judgement from Hilti or similar to accomplish. Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP Senior Member Username: specman Post Number: 1087 Registered: 03-2003 Posted on Thursday, February 07, 2013 - 03:41 pm:    A fire barrier is essentially a vertical element. Floor/ceiling and roof/ceiling assemblies are referred to as "Horizontal Assemblies" in the IBC and need to comply with Section 711 (2012 IBC). Horizontal assemblies may be rated or unrated as determined by Table 601 for construction types or Table 508.4 for occupancy separation. However, if a horizontal assembly is used in determining a "fire area," then they try to confuse you by placing the minimum required ratings of the horizontal assembly in the fire barrier requirements of Section 707 in Table 707.3.10. Ron Geren, AIA, CSI, CCS, CCCA, SCIP www.specsandcodes.com