The minimum requirements differ

Few of us think of a bedroom window as a “life saving” feature. Although bedroom windows are not considered ordinary escape routes, if there were ever to be an emergency situation, such as a house fire, having the right size escape window in the bedroom could be the difference between life and death. death. By the time an occupant can respond to a smoke alarm, the suite may be filled with smoke and their escape route from the bedroom blocked.

Did you know:

“…a bedroom in Ontario does not require an egress window in the actual bedroom.”

The requirement for a properly sized bedroom window has been around since 1980 and subsequent code changes since then have made it even easier to understand how a bedroom egress window is defined. Or do you have it? It depends on the code you are referencing. Regional requirements may differ from national regulations.

National Building Code of Canada

The National Building Code of Canada (NBCC), on which the Provincial Codes are based, has very clear requirements when it comes to bedroom windows and how the bedroom window serves three distinct purposes in the home:

1. Light (at least five percent of the area served)
2. Ventilation (at least 0.28 m² or 3 ft² or adequate mechanical ventilation throughout the year)
3. Emergency exit: An emergency escape requires that each bedroom have a door that leads directly to the exterior of the building or an exit window of adequate size that can be opened from the inside without the use of keys, tools, hardware, or special knowledge (unless this bedroom has a sprinkler system installed).

Building Code article 9.7.1.2. establishes the general requirement that all bedrooms must have at least one window that is large enough to be used as an exit in an emergency. The specific requirements are as follows:

1. Except where the suite has a sprinkler, each bedroom or combination bedroom shall have at least one exterior window or exterior door that can be operated from the interior without the use of keys, tools, or special knowledge and without removing frames or hardware.
2. The window referred to in Sentence (1) shall provide an unobstructed opening of not less than 0.35 m² (542 in² or 3.8 ft²) in an area with a dimension of not less than 380 mm (15 inches), and maintain the required opening during an emergency without the need for additional support.
3. If the window referred to in Sentence (1) is fitted with security bars, the security bars must be capable of being operated from the inside without the use of any tools or special knowledge.

If a window well is required, it should be outside the window by at least 550mm (about 22″) to provide safe passage. Awning style windows, for example, that open into a window well will not normally work because they tend to obstruct free passage unless the window well is unusually large.

It is further recommended that the bottom of any egress window opening or sill be no more than 5 ft (1.5 m) from the ground. Now this can be a bit of a challenge for any basement bedroom, so some built-ins under the window are required to help out in an emergency.

Ontario Building Code

This may come as a surprise to many people, or a relief to those looking to add a basement bedroom, but contrary to the National Building Code and popular writing, a bedroom in Ontario does not require an egress window in the actual bedroom! As long as there is an exit window or door to the outside somewhere on the level, the requirements for exit have been met. However, there are still light and ventilation requirements for each bedroom that must be met, but that is another topic.

Exit from the dormitories (OBC 9.9.10)

Windows or exit doors for bedrooms (9.9.10.1)

1. Except where a door on the same floor level as the bedroom provides direct access to the outside, each floor level containing a bedroom in a suite must have at least one exterior window that,
2. can be opened from the inside without the use of tools,
3. provides a single, unobstructed open portion having a minimum area of ​​0.35 m² (3.8 ft²) with a dimension of not less than 380 mm (15 inches), and
4. maintains the required opening described in Clause (b) without the need for additional support.
5. Except for basement areas, the window required in Sentence (1) shall have a maximum sill height of 1,000 mm (39 inches) above the floor.
6. When sliding windows are used, the minimum dimension described in sentence (1) shall apply to the openable part of the window.
7. When the sleeping area within a live/work unit is on an unobstructed mezzanine level more than 1070 mm above the floor, the window required in Sentence (1) may be provided on the main level of the live/work unit. provided that the crawl space is not more than 25% of the area of ​​the live/work unit or 20 m², whichever is less, and a direct, unobstructed path is provided from the crawl space to this window.
8. When a window required in Sentence (1) opens into a window well, a clearance of not less than 550 mm (22 inches) must be provided in front of the window.
9. Where a window sash referred to in Sentence (5) rotates into the window opening, the operation of the sash shall not reduce the clearance in a manner that would restrict escape in an emergency.
10. When a protective enclosure is installed over the window referred to in Sentence (5), such enclosure must be capable of being opened from the inside without the use of keys, tools, or special knowledge of the opening mechanism.

In summary, the required window size for egress is the same between the National Building Code and the Ontario Building Code. The window well requirements are also the same. The significant difference between the codes is that one means of egress is required for each bedroom under the National Building Code, whereas only one means of egress per level is required under the Ontario Building Code. Additionally, the National Building Code requires that the sill height from the floor not exceed 1,500 mm (59 in), while the Ontario Building Code requires that the sill height not exceed 1,000 mm (39 in).

International Residential Code

The International Residential Code (IRC), which is used in the United States, is even different. The IRC states that at least one window in each bedroom must be large enough to allow the occupants to escape a fire, AND also to allow a fully equipped firefighter to enter. The window size is also required to be larger than Canadian requirements. An egress window must meet the four criteria of the International Residential Code (IRC):

• Minimum opening width: 20 in.
• Minimum opening height: 24 in.
• Minimum net free opening: 5.7 m2. ft. (5.0 sf for the ground floor).
• Maximum sill height above floor: 44 in.

If you have questions about whether your existing bedroom windows meet Code safety requirements, or if you’re about to do a basement remodel that will involve windows, it’s always best to contact your local authorities. Local requirements may vary.