Ladder in MOE between Stories

[Mech]

2015 IBC

Proposed 3 story fully sprinkled non-separated F-1, S-2 occupancy addition to an existing 3 story B, F-1, S-2 occupancy. The existing building is partially sprinkled and partially separated by fire walls. The proposed and existing buildings will be separated via a 3 hr fire wall with one fire door on the first floor and one fire door on the second floor; both fire doors will be normally held open by fusible links.

The entire third floor of the proposed building is a refrigeration room, about 8,700 sf, with a 29 person occupant load. Per Table 1006.2.1, more than 1 exit or exit access doorway is required.

Section 1006.2.2.2 Refrigeration machinery rooms allows one exit access doorway to be served by a fixed ladder or alternating tread device.

Since the entire floor is a refrigeration machinery room, am I permitted to use a fixed ladder in one of the means of egress for the third floor?


Assuming a fixed ladder is allowed:
Is a fire rated shaft required? Section 1019 Exit Access Stairways and Ramps allows for openings without a shaft, but this is a ladder, not a stairway or a ramp. This ladder between the 2nd and 3rd floors is the only proposed unprotected opening to the 2nd floor.

Since the proposed first and second floors are connected to the existing building with normally held open fire doors, must I evaluate the existing building to see if the 2nd floor has unprotected openings to the 1st floor?

Section 1019.3 Occupancies other than Groups I-2 and I-3. In other than Group I-2 and I-3 occupancies, floor openings containing exit access stairways or ramps that do not comply with one of the conditions listed in this section shall be enclosed with a shaft enclosure constructed in accordance with Section 713.
1. Exit access stairways and ramps that serve or atmospherically communicate between only two stories. Such interconnected stories shall not be open to other stories. Again, the fire doors are held open with fusible links. If the existing building is open to more than two stories, would the proposed building be considered open to more than two stories since the fire doors are held open?
2 & 3 Omitted as these do not apply.
4. Exit access stairways and ramps in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, where the area of the vertical opening between stories does not exceed twice the horizontal projected area of the stairway or ramp and the opening is protected by a draft curtain and closely spaced sprinklers in accordance with NFPA 13. In other than Group B and M occupancies, this provision is limited to openings that do not connect more than four stories. This might be applicable, if the dimension of the ladder cage can be considered part of the projected horizontal area.
5 - 8 Omitted as these do not apply.

In case anyone is wondering, the floor construction per Table 601 does not require a fire rating.

The sprinkler is required for increased floor area, increased number of stories, Group F-1 Fire area greater than 12,000 sf, combined F-1 Fire area on all floors exceeds 24,000 sf, and insufficient exterior wall openings.

Thanks if you made it to the end and have any thoughts.​

 

[RLGA]

This is a common mistake that I see a lot of people make. Table 1006.2.1 is only for spaces—not stories. Stories are required to have two means of egress from a story per 1006.3.1 if the occupant load is 1 to 500 occupants.

Table 1006.3.2(2) would allow a single exit from an upper story, but does not allow it for the third story or higher for any occupancy group—you must have two means of egress.

Per your description, the third story would have two spaces since a fire wall separates the two buildings. Now, if you can put an opening in that wall, you have a horizontal exit—that’s exit #1. Put a stair in an exit enclosure or exterior exit stair with separate points of entry from each building—that’s exit #2.

FYI: The requirement for refrigeration machinery rooms is for the room that encloses the refrigeration equipment—not a room that is refrigerated for the purpose of keeping contents cold.

 

[Mech]

Thanks for the input Ron.

This area does meet the definition of a refrigeration machinery room, but it is too large to be considered a penthouse and must be called a 3rd story.​

As you corrected me, the third story requires two exits or access to exits. Stair tower #1, a three-story interior stairs, will serve all three proposed stories as the first exit.

Per 1006.2.2.2, a machinery room must have two exit access doorways, one of which can utilize a fixed ladder.

Since the entire third story is a refrigeration machinery room, can a fixed ladder be used in the second required exit? The ladder would lead to the second floor where the occupants have access to Stair tower #2, a two-story interior stairs. This would serve all three proposed stories as the second exit.

Or are (2) non-ladder using exits required from the third story, regardless of the story use?

The existing building is 100,000+ sf, and the existing third story only occurs at certain portions of the building, not near this addition, so a horizontal exit is not feasible.

Thanks

 

[steveray]

2 MOE for story....Ladder not allowed as MOE for story.....But maybe the BO could accept as a mod?

 

[Mech]

Update:

One of the consultants on the job does not like the ladder idea and has mandated the second stair tower be extended to the third floor level.