• Welcome to the new and improved Building Code Forum. We appreciate you being here and hope that you are getting the information that you need concerning all codes of the building trades. This is a free forum to the public due to the generosity of the Sawhorses, Corporate Supporters and Supporters who have upgraded their accounts. If you would like to have improved access to the forum please upgrade to Sawhorse by first logging in then clicking here: Upgrades

2015 IBC CORRIDORS 1020.1, Exception 4 applicable?

sergoodo

Sawhorse
Joined
Oct 27, 2009
Messages
263
2 story building, 2nd floor corridor with total of 40 cumulative occupants that egress into the space. At each end of the corridor is an Exit Access. Is Exception 4 applicable?

2015 IBC SECTION 1020 CORRIDORS
1020.1 Construction

Corridors shall be fire-resistance rated in accordance with Table 1020.1. The corridor walls required to be fire-resistance rated shall comply with Section 708 for fire partitions.
Exception 4: A fire-resistance rating is not required for corridors in an occupancy in Group B that is a space requiring only a single means of egress complying with Section 1006.2.
 

sergoodo

Sawhorse
Joined
Oct 27, 2009
Messages
263
No sprinkler, not a trick question.

Well, tricky when separating exit requirement code construction for 'a building' and 'a space'
 

lifesafetyinfo

Registered User
Joined
Sep 18, 2020
Messages
9
Location
Pittsburgh, PA
There's not a clear link in the text of the code, but I think the AHJ could make the case that table 1006.3.2 (2015 IBC) also applies which would limit you to 29 occupants on the 2nd floor above grade in a B occupancy. Over 29 occupants and table 1006.3.2 would require a second exit which would then take away the exception.
 

lifesafetyinfo

Registered User
Joined
Sep 18, 2020
Messages
9
Location
Pittsburgh, PA
I'm not sure where you going with this, but with an occupant load of 30 or more on the second floor you are required (2) exits.
That's exactly where I was going with my response. The one odd thing is that the exception only references 1006.2, but I still think the 29 occupant limit in 1006.3.2 would apply since the restriction for the floor would overrule any exceptions found in 1006.2.
 

sergoodo

Sawhorse
Joined
Oct 27, 2009
Messages
263
The exception is for the ‘space’. Yes, the Building requires 2 exits; but a ‘space’ that calculates 1 exit qualifies.

This is the same logic that a ‘space’ in a building, say a conference room on the 72nd floor, with an occupancy of 49, requires 1 exit. We all know that 97 story building requires 4 exits and that conference room on the 72nd floor does not require 4 exits.

Also know on the 72nd floor, in this scenario, there is another tenant’s 49 occupant office ‘space’ with a corridor that qualifies for the exception.

Otherwise glazed partition corridors, double loaded with offices and conference rooms, would not exist in skyscrapers
 

cda

Sawhorse 123
Joined
Oct 19, 2009
Messages
19,058
Location
Basement
If the floor requires two exits the space required two

Can you post a simple floor plan

Would help
 

lifesafetyinfo

Registered User
Joined
Sep 18, 2020
Messages
9
Location
Pittsburgh, PA
If there's a "corridor" within a "space" (meaning an occupancy or tennant space) then exception 4 to 1020.1 would allow the "corridor" to be unrated so long as only a single exit is required. Basically it's no longer a "corridor" (an enclosed exit access component), but more of a hall that just provides a route within the space to the single required means of egress. Picture something like a strip mall where an office with say 45 total occupants would all use a single door at the front of the space with no other exits.

In this case, the second floor of the building requires two means of egress since there are more than 29 occupants on the floor (table 1006.3.2). The corridor sounds like it connects both exit access points with each of the spaces exiting into the corridor. Each of the spaces only requires one means of egress, however the corridor in this case serves the overall second floor and therefore has two required means of egress. Exception 4 to 1020.1 doesn't apply because the corridor isn't happening within a space on the floor, it serves multiple spaces on the floor.

The only case I can see where a fire resistance rating would not be required for this corridor (unsprinklered B occupancy) is if the total occupant load served by the corridor was 30 or less (table 1020.1) - otherwise a 1 hour rating is required.

In the 72nd floor scenario, the building surely has a sprinkler system throughout for other reasons, so a rated corridor is not required in a B occupancy.
 

sergoodo

Sawhorse
Joined
Oct 27, 2009
Messages
263
If there's a "corridor" within a "space" (meaning an occupancy or tennant space) then exception 4 to 1020.1 would allow the "corridor" to be unrated so long as only a single exit is required. Basically it's no longer a "corridor" (an enclosed exit access component), but more of a hall that just provides a route within the space to the single required means of egress. Picture something like a strip mall where an office with say 45 total occupants would all use a single door at the front of the space with no other exits.

In this case, the second floor of the building requires two means of egress since there are more than 29 occupants on the floor (table 1006.3.2). The corridor sounds like it connects both exit access points with each of the spaces exiting into the corridor. Each of the spaces only requires one means of egress, however the corridor in this case serves the overall second floor and therefore has two required means of egress. Exception 4 to 1020.1 doesn't apply because the corridor isn't happening within a space on the floor, it serves multiple spaces on the floor.

The only case I can see where a fire resistance rating would not be required for this corridor (unsprinklered B occupancy) is if the total occupant load served by the corridor was 30 or less (table 1020.1) - otherwise a 1 hour rating is required.

In the 72nd floor scenario, the building surely has a sprinkler system throughout for other reasons, so a rated corridor is not required in a B occupancy.

Good point with the sprinkler factored into the scenario! Not gonna post that pretty picture of a glass corridor now.

The space can be 8 offices; an entire floor with 40 occupants. Or
The space can be 8 offices, 2 tenants; an entire floor with 40 occupants.
Requiring the rated corridor for 2 tenants is an arbitrary application of code to determine the exception. Space with 40 occupants require 1 exit, 2nd story requires 2 exits. Any corridor providing exit access to one or both exits is not required to be rated.1020.1 Exception 4

40 occupants in a space that requires 1 exit per TABLE 1006.2.1. SPACES WITH ONE EXIT: Yes, meets qualification for 1020.1 Exception 4
40 occupants on a story requiring 2 exits 1006.3.2(2) STORIES WITH ONE EXIT Yes, but not a qualification for 1020.1 Exception 4
 

sergoodo

Sawhorse
Joined
Oct 27, 2009
Messages
263
So what is the question???

Will have to look at two floors open to each other.

Looks like you are good with that
Is 1020.1 exception 4 applicable to a 2nd story space with an occupancy of 40 (occupancy <49)?
I say yes
 

sergoodo

Sawhorse
Joined
Oct 27, 2009
Messages
263
unless I am missing something

A sprinkler building does not require rated corridors

non sprinkled B Occ bldg...
Is 1020.1 exception 4 applicable to the 2nd story space with an occupancy of 40 (occupancy <49)?
I say yes
 

cda

Sawhorse 123
Joined
Oct 19, 2009
Messages
19,058
Location
Basement
non sprinkled B Occ bldg...
Is 1020.1 exception 4 applicable to the 2nd story space with an occupancy of 40 (occupancy <49)?
I say yes

Sprinkler question asked and answered

Sorry I thought it was sprinkled
 
Top