R310.5

Section R310.5 is titled 'Dwelling additions' and covers requirements for providing secondary exiting. The requirement to add an emergency escape and rescue opening (EERO) in sleeping rooms and basements of new additions is established. The purpose of this section is to provide secondary means for exiting from new additions in the event the primary means of egress is blocked. This section has 2 exceptions which exempt the need for a basement addition to have an EERO where the existing basement already contains one (either in a sleeping room or other area) and is accessible from the addition. The purpose of these exceptions is to clarify that redundancy of EEROs is not intended for basement additions.

The model shows the skin of an existing dwelling with an addition which has highlighted EERO locations. Three different arrangements are demonstrated: A basement addition (either a sleeping room or other area) where the existing basement does not have an existing EERO; a basement addition with a new sleeping room where the existing basement has an existing EERO (either in an existing sleeping room or other area); and a basement addition that is not a sleeping room, where the existing basement has an existing EERO (either in an existing sleeping room or other area).