When Do You Need More Than One Door? – Spaces That Require More Than One Means of Egress

The 2006 International Building Code spells out the conditions where you are required to have two or more exits or as I prefer to see it, where you can have only one exit from a space. Generally the requirements are straight forward but there are a few complex conditions that I’ve called out.

The first test is occupant load. For occupancy types A, B, E, F, M, and U you can have up to 49 occupants with one exit. For day care centers in type E you’re limited to 10 with one exit. For H-1, H-2 and H-3 you can have 3 occupants with one exit and for H-4, H-5, I-1, I-4, I-4 and R you can have 10 occupants. S occupancy allows 29 occupants with one exit. I-2 has a long list of requirements, let me know if you need to go through them.

The next test is common path of egress travel, basically how far you have to go to get to the exit door. For H-1, H-2 and H-3 you are limited to 25 feet with one exit. For other occupancies you’re limited to 75 feet with one exit. There are several exceptions. If you have a group B, F or S and a sprinkled building you can go 100 feet on one exit.  If you have a group B, S or F and no more than 30 occupants you can also have 100 feet to get to the one exit. Group I-3 is allowed 100 feet. In a sprinkled R-2 building you can go up to 125 feet. Assembly spaces have a number of additional requirements, again just let me know if you need them.

Finally there are a number of cases that always require two or more exits. Boiler, incenerator and furnace rooms over 500 sf or over 400,000 Btu in fuel fired equipment require two exits. Refrigerator machinery rooms over 1,000 sf require two doors. Refrigerated rooms over 1,000 sf and maintaining a temperature below 68 degrees  require two exits.

Please note that there is a different set of requirements for buildings with only one exit than this list for spaces with only one exit. I’ll cover that in a future post.


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