Fire Code - Maximum Travel Distance to Exit 2

[KB4444]

Not necessarily a structural question but I am working on a design with catwalks located above a network of bins. I need to determine what is required to meet code (NFPA 101 - Life Safety Code). My questions are below but here is the background for them. The catwalks are supported off of the bins. Some of the bins are different sizes, causing a few catwalks to be at different elevations. Ladders are used connect access from catwalk to catwalk (~15ft tall). I have reviewed the code and found the maximum travel distance to exit allowable is 200 ft.

When determining maximum travel distance to the exit:
1) What classifies as the exit?
a) Is this the ladder leading to the different platform?
b) Is it the ladder leading to the ground?

2) Does the travel distance on the ladder need to be included? (i.e. if the distance to the ladder is 200ft and the ladder is 50ft is the travel distance 250ft or 200ft)

 

[JLNJ]

I'm not an architect, but here goes.

An "Exit" is defined in the code, but it generally means outside to safety. Certain situations provide for an increase in travel distance. For example, if you pass through a fire wall your distance restarts.

I'm not sure that NFPA allows ladders to be used as a means of egress from a maintenance platform or how they treat ladder length. Stair length certainly counts. OSHA has taken a firm stance against ladders and tightened up their stair requirements due to so many falls on ladders and stairs.

 

[AgMechEngr]

A ladder cannot serve as a means of egress, but a ladder is allowable for accessing catwalks leading to nonoccupiable spaces. I assume that this catwalk does not lead to an office, so the catwalk is not itself a means of egress. Your travel distance calculations will be from an occupied space to an exit. Without more information about your project, I think you are going to be designing around OSHA related requirements like handrails, fall arrest systems on ladders, etc. more than anything.

 

[DBronson]

KB4444:

To better understand the issues I would carefully review the definitions in 101. An exit should be defined in there. Generally it's a point where one enters an outdoor public way - where a person is "safe". Catwalks and such are not usually considered "occupiable spaces" - people don't normally spend a lot of time there. So exit requirements are not applicable. And as AgMechEngr points out ladders are not allowed as means of egress. I would worry more about someone getting trapped on the catwalk system if the were a fire blocking the ladder. Adding a second ladder at the opposite end would alleviate this concern. In any case I would not design something like this without a discussion with the AHJ. The AHJ would be able to determine where the exit distance measurement would begin.

Regards,

DB

NB: Also, watch out for common path of travel issues.