Exceptions to enclosed Exit Enclosures

[MarkRandall]

The 2003 & 2006 IBC, chapter 10 for exit enclosures had exceptions #8 & #9 that allowed unenclosed stairways in sprinklered buildings serving adjacent floors or 2 story buildings.

Reviewing this for the first time in 2009 code, these 2 exceptions are not listed in Section 1022 Exit Enclosures. Are these exceptions eliminated or found somewhere else in the code? I can't imagine they were eliminated, but I haven't yet found where else this could be covered.

 

[Coug Dad]

I think the 2009 moved it to 1016.1 (I hope) I need to research further though.

 

[mtlogcabin]

Yes 1016.1 exception 4 i believe covers it as long as it does not exceed the travel distances in Table 1016.1

 

[MarkRandall]

Thanks Coug Dad & mtlogcabin.

 

[MarkRandall]

Section 1016.1Exception:

4. In other than occupancy Groups H and I, exit access travel distance is permitted to be measured from the most remote point within a building to an exit using unenclosed exit access stairways or ramps in the first and second stories above grade plane in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1. The first and second stories above grade plane shall be provided with at least two means of egress. Such interconnected stories shall not be open to other stories.

Coming back to the issue of enclosed & unenclosed stairways:

Building is two stories, sprinklered, unlimited area. The existing 2nd floor (B occupancy) is served by 4 stairways (two of which are enclosed). The client is adding another 8,800 SF of second floor space (B occupancy) in what is now warehouse space. Existing stairways/exits are within the travel distance of table 1016.1 (300'), so there are no requirements for additional stairways. The client is requesting two more stairways to be added.

If I'm interpreting this correctly, neither of the new stairs are required to be enclosed since existing stairs are already provided within travel distances. The new stairways will reduce the travel distances further.

Just making sure I'm not missing something. I thought 50% of the stairs had to be enclosed under previous codes. 2009 code seems to eliminate the 50% rule and allows as many unenclosed stairs as desired as long as travel distances are met. Correct?

 

[texasbo]

Mark, in 2 story fully sprinklered (other than H and I) building, none needed to be enclosed in 2006 or 2009. 1020.1, Exception 9, 2006 IBC.

 

[mtlogcabin]

If you are under the 2009 unless I am missing something they have to be enclosed. Exception 9 of the 2006 is no longer there

SECTION 1022

EXIT ENCLOSURES

1022.1 Enclosures required.

Interior exit stairways and interior exit ramps shall be enclosed with fire barriers constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 712, or both. Exit enclosures shall have a fire-resistance rating of not less than 2 hours where connecting four stories or more and not less than 1 hour where connecting less than four stories. The number of stories connected by the exit enclosure shall include any basements but not any mezzanines . Exit enclosures shall have a fire-resistance rating not less than the floor assembly penetrated, but need not exceed 2 hours. Exit enclosures shall lead directly to the exterior of the building or shall be extended to the exterior of the building with an exit passageway conforming to the requirements of Section 1023, except as permitted in Section 1027.1. An exit enclosure shall not be used for any purpose other than means of egress .

Exceptions:

1. In all occupancies, other than Group H and I occupancies, a stairway is not required to be enclosed when the stairway serves an occupant load of less than 10 and the stairway complies with either Item 1.1 or 1.2. In all cases, the maximum number of connecting open stories shall not exceed two.

1.1. The stairway is open to not more than one story above its level of exit discharge ; or

1.2. The stairway is open to not more than one story below its level of exit discharge .

2. Exits in buildings of Group A-5 where all portions of the means of egress are essentially open to the outside need not be enclosed.

3. Stairways serving and contained within a single residential dwelling unit or sleeping unit in Group R-1, R-2 or R-3 occupancies are not required to be enclosed.

4. Stairways in open parking structures that serve only the parking structure are not required to be enclosed.

5. Stairways in Group I-3 occupancies, as provided for in Section 408.3.8, are not required to be enclosed.

6. Means of egress stairways as required by Sections 410.5.3 and 1015.6.1 are not required to be enclosed.

7. Means of egress stairways from balconies, galleries or press boxes as provided for in Section 1028.5.1 are not required to be enclosed.

 

[texasbo]

2009 IBC: 1016.1, Exceptions 3 and 4 allows unenclosed exit access stairs (as opposed to exit stairs, which must be enclosed per 1022.1). Also see Sec 708.2, Exception 11.

The provisions were made more confusing.

 

[MarkRandall]

texasbo,

Thanks for confirming my code research.

Exiting of this building was last analyzed under 2003 IBC when current client\owner bought the building and did alterations. I'm glad some things regarding 2 story sprinklered buildings have lightened up since 2003 IBC (especially smoke control). Over the years, I've just become accustomed to regulations getting stiffer each cycle.