We have been asked to investigate the requirements for an external egress ladder for a building addition (on top of an existing building) to a feed mill plant.  There is an internal stair included in the proposed new construction.  I can't find any regulations regarding ladders, cages, landing heights, cat walks, distances, etc for this application.  Can anyone direct me to a resource?  I've checked IBC and don't find much regarding ladders.  Thanks in advance.