The International building code 2015/2018, Florida Building Code 2017,2020, and corresponding Residential Codes list the following in regards to egress as an emergency escape in regards to windows & doors leading out of a dwelling. Please note that these may be paraphrased and are for general purposes only. Consult the actual code for specific requirements. test in [brackets] are our opinions
1030.1 General. In addition to the means of egress required by this chapter, provisions shall be made for emergency escape and rescue openings in Group R-2 occupancies in accordance with Tables 1006.3.2(1) and 1006.3.2(2) and Group R-3 occupancies.
IBC / FBC 1030.1 / FRC Section R310.1: EMERGENCY ESCAPE AND RESCUE OPENINGS Basements, habitable attics and every sleeping room shall have not less than one operable emergency escape and rescue opening.
Exception 2: The emergency escape and rescue opening shall be permitted to open into a screen enclosure, open to the atmosphere, where a screen door is provided leading away from the residence. [Note, it does not say to anther enclosed room or glass enclosure]
IBC / FBC 1030.2 / R301.2.1: Minimum size. Emergency escape and rescue openings shall have a minimum net clear opening of 5.7 square feet
Exception: The minimum net clear opening for grade floor emergency escape and rescue openings shall be 5 square feet. [meaning first floor, others to be slightly larger]
IBC/ FBC 1020.2.1 / R310.2.1 The net clear height opening shall be not less than 24 inches and the net clear width shall be not less than 20 inches [Note: 20W X 24H does not equal min opening size so one of these shall be larger].
IBC /FBC 1030.3 / 310.2.2 Window sill height. Where a window is provided as the emergency escape and rescue opening, it shall have a sill height of not more than 44 inches above the floor; where the sill height is below grade, it shall be provided with a window well in accordance with Section R310.2.3 [we read this as inclusive of frame height when operable window is open].
IBC / FBC 1030.4 / R310.1.1 Operational constraints. Emergency escape and rescue openings shall be operational from the inside of the room without the use of keys or tools. Bars, grilles, grates or similar devices are permitted to be placed over emergency escape and rescue openings provided the minimum net clear opening size complies with Section 1030.2 and such devices shall be releasable or removable from the inside without the use of a key, tool or force greater than that which is required for normal operation of the emergency escape and rescue opening. Where such bars, grilles, grates or similar devices are installed in existing buildings, smoke alarms shall be installed in accordance with Section 907.2.11 regardless of the valuation of the alteration.
[Similar text exists in the residential code] R310.1.1 Operational constraints & Opening Control.Operational constraints and opening control devices. Emergency escape and rescue openings shall be operational from the inside of the room without the use of keys, tools or special knowledge. Window opening control devices complying with ASTM F2090 shall be permitted for use on windows serving as a required emergency escape and rescue opening.
R310.2.5 Replacement windows. Replacement windows installed in buildings meeting the scope of this code shall be exempt from the maximum sill height requirements of Sections R310.1 and Sections R310.2.1 and R310.2.2, provided the replacement window meets the following conditions:
1. The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window is of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.
2. The replacement window is not part of a change of occupancy.