If the sill is below ground the window itself will need larger dimensions 9 square feet.
Attic egress window requirements.
Please be aware of the definition and egress requirements of a habitable attic as it relates to dwellings built from the 2012 irc.
Basement egress windows have special requirements.
The window must open a minimum height of 24 inches.
The clear opening must add up to 5 7 square feet.
This would imply that some egress windows are expected to be more than 15 or 20 ft.
Have a minimum net opening area of at least 5 7 square feet.
It states that all egress windows must have a minimum width of 20 inches a minimum height of 24 inches minimum clearing of 5 7 square feet when opened and maximum sill height of 44 inches from the floor.
The minimum egress window opening height is 24 high.
Attics that meet the size and ceiling height criteria of the habitable attic definition in chapter 2 are considered habitable.
Attic egress openings must.
Have a minimum opening height of at least 24 inches.
Since you re below ground you have to make sure that the window can still fully open without obstruction.
Also note that if a window is being used to meet the egress requirements in addition to the above the sill height of the window shall not be more than 44 inches above the finished floor.
Irc r310 1 requires all sleeping rooms to have emergency escape and rescue openings however i think the irc is limited to 3 story residences.
The window must open a minimum width of 20 inches.
Since the staircase to the attic can act as a chimney for the fire to quickly spread it s necessary to have a secondary point of egress or exit.
The trickiest part is the window egress.
When a door is being used to meet the egress requirements it must be either a side hinged door or a slider.
Have a minimum opening width of at least 20 inches.
The minimum egress window opening is 20 wide.
Make sure the basement window well has enough area to move around in and if the well is especially deep make sure you have a ladder attached to it for an easy.
Attics are the worst place to be in a fire because heat and fire rise rapidly.
The 2009 and 2015 irc verbiage is similar and still applicable.
Having said that there are some broad standards dictated by the international residential code irc.
To qualify a basement window as an egress you may also have to install window wells to enlarge windows and allow access.
The minimum opening area of the egress window is 5 7 square feet.
The base of the well can be no more than 44 inches above the bedroom floor.
The egress window must have a glass area of not less than 8 of the total floor area of room s for which it is servicing to allow the minimum amount of sufficient natural light.