• 1009 accessible means of egress > 1009.3 stairways states 48” min between handrails i guess...?

• Jon,

This is a scenario where the stricter requirement will govern how wide your stair is.  Essentially here's how you do this:

1) You are right, you'll start with your occupant load that the stairs are going to serve, using Table 1004.1.2 to determine what that load is.  Then let's say you have 2 stairs.  You'll divide that occupant load by 2, and that number will be the number for each of those stairs.  Let's call that Number A.

2) Yes, you go to the code about the stair width factors (the 0.3 and 0.2 that you identified) and you'll do your calculation.  Whether or not you can use 0.3 or 0.2 to do this calculation depends on the criteria listed in the code.  Off the top of my head, it has to do with sprinklers and an emergency communication system being in the stair that allows you to use the lesser factor.  For the ARE, they would tell you if your building had these items so that you would know which factor you could use in your calculation.

3) You are correct again, once you do this calculation for the stair width, and let's say you get 24" as your answer, yes, the 44" width minimum requirement that you correctly identify above would override that because it is stricter.  However, you might find that instead of 24", you calculation for the stair is something greater than 44".  In that case, that calculation would govern.  Whichever number is bigger.

4) The accessible means of egress (48" clear handrail width) may come into play as well.  If it does, then yes, 48" would govern over the 44" width.  Or, if your calculation you did nets a number greater than 48", then THAT number would govern.

The biggest number wins.  Period.

I think you got this.

• THANK YOU. /super/ helpful to get help from a pro. it’s very hard to find...