712.1.3.1 Opening size.
BC § 712.1.3.1
Protection by a draft curtain and closely spaced sprinklers in accordance with NFPA 13, as modified by Appendix Q of this code, shall be permitted where the area of the vertical opening between stories does not exceed twice the horizontal projected area of the escalator or stairway. In other than Groups B and M, this application is limited to openings that do not connect more than four stories.













