Dead End Corridor

"dead end corridor"

Maximum Allowed Length of a Dead End Corridor

Section BC 1002.1 Definitions  - A DEAD END corridor is a portion of a corridor in which the travel to an exit is in one direction only.

Section BC 1016.3 Dead Ends - In spaces where two means of egress are required, the Building Code restricts the length of corridor allowed to be a DEAD END to 20 feet with the following exceptions:

1. In Group I-3 of Occupancy Condition 2, 3 or 4 (see Section 308.4) – 50 feet max
2. In occupancies in Group B and F in buildings equipped throughout with automatic sprinkler in accordance with Section 903.3.1.1 – 50 feet max
3. Dead-end length not exceeding 2.5 times the least width of the dead end corridor. (Tip: This can increase the allowed maximum length of dead end corridor to more than 20 feet if the width of the dead end corridor is greater than 8 ft).
4. In occupancies in Group R-2 – 40 feet max dead end. However, if corridors are completely enclosed in construction having a 2hr fire resistance rating with doors opening onto corridor being self-closing and having a 1.5 hr fire resistance rating – 80 feet max

BC Sections above are paraphrased. Please see actual BC Section for exact language.

Dead End Corridors: When do I really need to be worried about the length?

Well, always actually. But especially if you are using a scissor stair as your two means of egress. This is because there is more of a chance that you will end up with a long dead end corridor with a scissor stair than with two separate stairs located on disparate ends of your building.

Dead End Corridors for Dummies

In case of fire, it’s good to have options. You never know where  a fire may start and if fire, smoke or heat is blocking your path to safety it is good to know that you can turn around and take another route. In the above example, a scissor stair provides two means of egress for residents of this apartment building. However, this corridor has two DEAD ENDS. This means that in case of fire, residents coming out of apartments A,B,D,E,F and G only have one possible direction they can go to get to a stair. Therefore, it makes sense to want to place a maximum limit on the length of a DEAD END corridor.

Still confused about what portion of the corridor is counted as a Dead End? Read this example and you’ll remember forever.

So let’s say the resident in apartment E fell asleep while cooking a grill cheese. His delectable afternoon snack burst into flames, causing a cheesy haze of smoke and flames to ooze out into the corridor. The fire alarm is triggered and the residents of apartment F and G come out into the corridor to find themselves confronted with a haze of smoke. It would be great if they could turn around and run walk calmly in the opposite direction of the blaze to an egress stair. But they can’t, because the entry doors to both Stair A and B are in the same direction of travel (west) – therefore, they are in a DEAD END portion of the corridor. So you can see how this is not a very desirable situation to be in. So, the Building Code restricts the length of a DEAD END corridor. This decreases the likelihood that a cheesy haze of smoke might block your path, and how long of a path you may have to safety.

 


© Copyright2013 Building Code Sketchbook