Why Is Egress Important?

E: msmithic@msn.com | T: 215-601-0800

What is an egress window?

An egress window is a window that is required in specific locations in a dwelling and is intended to provide an emergency means of exiting a dwelling. Windows must meet specific size requirements to qualify as an egress window.

Where are egress windows required?

Egress windows are required in every room used for sleeping purposes (bedrooms) on any floor and in basements with habitable space. If you are constructing a new home, the code requires that you put an egress window in each bedroom. It also requires an egress window in the basement if habitable rooms will be finished in the basement. If you install a basement bedroom or bedrooms, an egress window is required in each bedroom but you need not provide another egress window if there are other habitable rooms in the basement. The bedroom window(s) suffices for the habitable rooms.

If you have an existing home and you add a sleeping room in an unfinished basement, the code requires that you install an egress window in the sleeping room or rooms. Likewise, if you create habitable space in your basement other than a bedroom and you currently do not have an egress window, the code would require that you install one as part of the installation of the habitable room.

What are the size requirements for an egress window?

An egress window must satisfy four International Residential Code (IRC) criteria:

  • Minimum width of opening: 20 in.
  • Minimum height of opening: 24 in.
  • Minimum net clear opening: 5.7 sq. ft. (5.0 sq. ft. for ground floor).
  • Maximum sill height above floor: 44 in.

The window must have a minimum net clear opening of 5.7 sq. ft. Net clear opening refers to the actual free and clear space that exists when the window is open. It is not the rough opening size or the glass panel size, but the actual opening a person can crawl through.

The window opening must be operational from the inside without keys or tools. Bars, grilles and grates may be installed over windows but must be operational without tools or keys and still allow the minimum clear opening.

Must I use a special type of window?

A wide variety of window designs can be used for egress windows. You should select a window design that meets your architectural, aesthetic, space, and financial limitations.

Note: Dimensions shown are only for illustrative purposes.

Casement windows with hinged sashes that swing free and clear of the opening can be relatively small and still meet egress requirements. This makes them ideal for basement egress and for other areas where space is limited.

Some manufacturers can install a special operator arm that allows the window to open wider than the standard operating arm to meet egress requirements. Others have an operator arm that can be pushed to open the window wider in an emergency. These meet egress requirements as long as you leave the “PUSH HERE” label in place.

Note: Dimensions shown are only for illustrative purposes.

Glider or slider windows have sashes that fill nearly half the possible window opening. They require a window nearly twice the size of a casement window.

Even when it’s fully open, more than half of a double-hung window’s overall area is blocked by glass.

This means that to meet egress window height requirements, a window must be nearly 4 ft. 9 in. in overall height.

This height requirement makes it undesirable for most basement egress situations.
Awning window

Awning windows are problematic. Since the opened sash prevents escape from most window wells, they’re unsuitable for basement egress. And with most awning windows, the center opening hardware and height don’t meet egress requirements. Some manufacturers offer models with special detachable operators that meet egress requirements.

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