Stories with one exit across a roof

[Mech]

2009 IBC

A second story occupancy, used as storage, with a single means of egress is proposed across the first floor roof and down an unenclosed stairs. Where is the maximum 75 ft travel distance measured? I am thinking it is measured to the point where an occupant is no longer on the stairs but at grade. Is this correct?

Table 1021.2 Stories with one Exit

TABLE 1021.2 STORIES WITH ONE EXIT

[TABLE=class: grid, width: 640]

[TR]

[TD]STORY[/TD]

[TD]OCCUPANCY[/TD]

[TD]MAXIMUM OCCUPANTS (OR DWELLING UNITS)PER FLOOR AND TRAVEL DISTANCE[/TD]

[/TR]

[TR]

[TD]First story or basement[/TD]

[TD]A, Bd, Ee, Fd, M, U, Sd[/TD]

[TD]49 occupants and 75 feet travel distance[/TD]

[/TR]

[TR]

[TD]H-2, H-3[/TD]

[TD]3 occupants and 25 feet travel distance[/TD]

[/TR]

[TR]

[TD]H-4, H-5, I, R[/TD]

[TD]10 occupants and 75 feet travel distance[/TD]

[/TR]

[TR]

[TD]Sa[/TD]

[TD]29 occupants and 100 feet travel distance[/TD]

[/TR]

[TR]

[TD]Second story[/TD]

[TD]Bb, F, M, Sa[/TD]

[TD]29 occupants and 75 feet travel distance[/TD]

[/TR]

[TR]

[TD]R-2[/TD]

[TD]4 dwelling units and 50 feet travel distance[/TD]

[/TR]

[TR]

[TD]Third story[/TD]

[TD]R-2c[/TD]

[TD]4 dwelling units and 50 feet travel distance[/TD]

[/TR]

[/TABLE]

For SI: 1 foot = 304.8 mm.

a. For the required number of exits for parking structures, see Section 1021.1.2.

b. For the required number of exits for air traffic control towers, see Section 412.3.

c. Buildings classified as Group R-2 equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 and provided with emergency escape and rescue openings in accordance with Section 1029.

d. Group B, F and S occupancies in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 shall have a maximum travel distance of 100 feet.

e. Day care occupancies shall have a maximum occupant load of 10.

 

[steveray]

If I understand correctly....the bottom of the stairs.....that would be the "safe point"...Or another way, since there is no protected exit, you would have to go to the exit discharge, which would be the bottom of the stairs...

 

[Mech]

The bottom of the stairs is the point at which an occupant can travel towards the parking lot and walkway to the main entrance of the first floor or travel towards the back side of the building.

 

[steveray]

What use is it? I know they rediculously increased it for apartments in the 2012....

TABLE 1021.2(1) STORIES WITH ONE EXIT OR ACCESS TO ONE EXIT FOR R-2 OCCUPANCIES

STORY OCCUPANCY MAXIMUM NUMBER OF DWELLING UNITS MAXIMUM EXIT ACCESS TRAVEL DISTANCE

Basement, first, second or third story R-2a, b 4 dwelling units 125 feet

Fourth story and above NP NA NA

 

[Mech]

Oops, I guess I edited that part out accidentally. The existing second floor is storage. The existing first floor is I-2. The second floor area is less than 1,500 sq ft.; accessibility is not required. The occupant load is less than 10.

 

[steveray]

You get 29 people and 100ft in 2012 if that helps....What is your distance to the bottom of the stairs?

 

[Mech]

2009 IBC allows 29 people and 100 ft as well. It is 120 feet to the bottom of the stairs (83 feet to get to the edge of the roof and another 37 feet across an elevated walkway and down the stairs.)