Is Large Circulation Space a 'Corridor' in NFPA 101?

2/13/2025

Subject: Two story convenience opening separation from corridors.

NFPA 101 (2021 edition) Section 8.6.9.1 permits convenience openings for two adjacent stories. But, these convenience openings shall be separated from corridors (requirement #3) and further states that separation should be by a smoke partition (requirement #5).

How do you define a corridor versus an open floor area or lobby per NFPA 101, since no definitions are given within the code?

Jurisdiction is required to follow NFPA 1 and NFPA 101.

For example, a building has a large assembly space on the second floor. All doors from the assembly space lead to a ~40'-0" wide circulation space (+200'-0" long in the other direction). To reach the building exit stair, occupants from the assembly room must traverse the 40'-0" wide circulation space. Within this circulation space is a ~20'-0" x 40'-0" vertical opening that connects the 1st and 2nd floor.

Should this circulation space be considered a corridor, and should the vertical opening be prohibited from being classified as a convenience opening without a smoke partition separating from the corridor?

Or is the 2nd floor space to be considered an open floor area, with exits immediately accessible in different directions (NFPA 101 7.5.1.1.1) and not consider it a corridor?

The width of the circulation space seems too wide to be defined as a corridor but NFPA only provides minimum width requirements for corridors, and no maximum width for a space to be considered a corridor as far as I can determine.

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6 Comments

Christopher Hallock

2/13/2025 08:47:11 am

NFPA 101 12.3.1(3) seems to permit this exact circumstance.

12.3.1 states:

"Any vertical opening shall be enclosed or protected in accordance with Section 8.6, unless otherwise permitted by one of the following:"

Then, 12.3.1(3) states:

"Assembly occupancies protected by an approved, supervised automatic sprinkler system in accordance with Section 9.7 shall be permitted to have unprotected vertical openings between any two adjacent floors, provided that such openings are separated from unprotected vertical openings serving other floors by a barrier complying with 8.6.5."

12.3.1(3) does not require separation from corridors and thus is "otherwise permitted".

This assumes that the occupancy classification is assembly.

Glenn Berger

2/13/2025 09:01:35 am

There is no code that can possibly define all "words" that are contain within its document.

Against my better judgement, this is one of those cases that I will utilize the definition from the IBC or even a dictionary. The IBC does define a corridor "as an enclosed exit access component that defines and provides a path of egress travel."

In your example who do not have an defined enclosure and as such the convenience opening is allowed.

JackG

2/13/2025 12:50:49 pm

In the 3 states/and large cities that I work in, the “ life safety codes “ are not” recognized as part of the code. ( sprinkler omissions )
NFPA 13 requires sprinklers with draft stops around those openings, if the convience is recognized as part of the egress. The wall / walls would require a fire rating.

Todd E Wyatt

2/14/2025 08:39:13 am

If a term (CORRIDOR) is not defined in the applicable Code, NFPA 101 Life Safety Code (LSC), then the “Merriam-Webster’s Collegiate Dictionary, 11th edition, shall be the source for the ordinarily accepted meaning” per LSC-2024 3.1.

Merriam-Webster’s Collegiate Dictionary
Corridor
noun
1 : a passageway (as in a hotel or office building) into which compartments or rooms open,
2 : a usually narrow passageway or route

This does not help differentiate IF this is a CORRIODR or not since the (2) “Convenience Opening” (CO) and the story’s Exit Access to the (2) Interior Exit Stairways (IES) both existing in this same area. This area could be interpreted to be a “LOBBY” versus a “CORRIDOR” which would NOT require it to be protected from the adjacent Assembly and Storage spaces.

If the LSC is the only applicable scoping Code for this project (e.g. no IBC), the first step in evaluating the compliance of this is to determine the OCCUPANCY CLASSIFICATION(S) (OC) of the portion of the stories that the CO occurs.

LSC-2024 includes the following suggested procedure for determining the Code requirements for a building or structure:

A.1.1
1) Determine the OCCUPANCY CLASSIFICATION by referring to the occupancy definitions in Chapter 6 and the occupancy Chapters 12 through 42. (See 6.1.14 for buildings with more than one use.)
2) Determine if the building or structure is new or existing. (See the definitions in Chapter 3.)
3) Determine the occupant load. (See 7.3.1.)
4) Determine the hazard of contents. (See Section 6.2.)
5) Refer to the APPLICABLE OCCUPANCY CHAPTER of the Code, Chapters 12 through 42. [See Chapters 1 through 4 and Chapters 6 through 11, as needed, for general information (such as definitions) or as directed by the occupancy chapter.]
6) Determine the OCCUPANCY SUBCLASSIFICATION OR SPECIAL USE CONDITION, if any, by referring to Chapters 16 and 17, day care occupancies; Chapters 18 and 19, health care occupancies; Chapters 22 and 23, detention and correctional occupancies; Chapters 28 and 29, hotels and dormitories; Chapters 32 and 33, residential board and care occupancies; Chapters 36 and 37, mercantile occupancies; and Chapter 40, industrial occupancies, which contain subclassifications or special use definitions.
7) Proceed through the applicable OCCUPANCY CHAPTER to verify compliance with each referenced section, subsection, paragraph, subparagraph, and referenced codes, standards, and other documents.
8) Where two or more requirements apply, refer to the OCCUPANCY CHAPTER, which GENERALLY TAKES PRECEDENCE over the base Chapters 1 through 4 and Chapters 6 through 11.
9) Where TWO OR MORE OCCUPANCY CHAPTERS APPLY, such as in a mixed occupancy (see 6.1.14), apply the MOST RESTRICTIVE requirements.

Some OCs (e.g. New Health Care - NHC) require that the “EXIT ACCESS CORRIDOR” (EAC) be separated from occupied rooms/spaces by partitions that “resist the passage of smoke”. NHCs also do not permit COs. This is why it is imperative to FIRST determine the OCs.

2/14/2025 08:46:07 am

Chances are, the IBC (e.g. IBC-2024) is the applicable Code. See the following for requirements for this “TWO-STORY OPENING” (TSO) :

IBC-2024
Chapter 7 Fire and Smoke Protection Features
Section 712 Vertical Openings
712.1.9 Two-Story Openings
In other than Groups I-2 and I-3, a vertical opening that is not used as one of the applications specified in this section shall be permitted if the opening complies with ALL of the following items:
1) Does not connect more than two stories.
2) Does not penetrate a horizontal assembly that separates fire areas or smoke barriers that separate smoke compartments.
3) Is not concealed within the construction of a wall or a floor/ceiling assembly.
4) Is not open to a corridor in Group I and R occupancies.
5) Is not open to a corridor on nonsprinklered floors.
6) Is separated from floor openings and air transfer openings serving other floors by construction conforming to required shaft enclosures.

2/15/2025 09:24:34 am

While the circulation space (to the left of the 2 storage rooms and the 2 assembly spaces) with the (2) two-story openings (TSO) and/or the (2) Convenience Openings (CO) could be argued that they do not meet the definition and/or intent of a "corridor", the passageway at the top of the upper storage leading to the top Interior Exit Stairway (IES) does meet the definition and/or intent of a "corridor" and should be separated from the TSO/CO.

Is Large Circulation Space a 'Corridor' in NFPA 101?

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