Because so many fire deaths occur when occupants of residential buildings are asleep at the time of a fire, the C.B.C. requires that:
- basements in dwelling units; and,
- every sleeping room below the fourth story shall:
have at least one operable window or door approved for emergency egress and rescue. This exit shall open directly into a public street, public alley, yard or exit court. The units shall be operable from the inside to provide a full clear opening without the use of separate tools or knowledge.
Extensive testing by building and fire departments established the minimum size window requirements found in section 310.4:
- The net clear openable area shall be no less than 5.7 square feet.
- In addition to the above requirement, the net clear openable height dimension shall be a minimum of 24 inches. The net clear openable width dimension shall be a minimum of 20 inches. (Note: Using both minimum figures will NOT obtain the required 5.7 square feet).
- The finished sill height shall not be more than 44 inches above the floor.
Minimum Width/Height Requirements
for Emergency Escape and Rescue Windows
|
Width
|
20
|
20.5
|
21
|
21.5
|
22
|
22.5
|
23
|
23.5
|
24
|
24.5
|
25
|
25.5
|
26
|
26.5
|
27
|
|
Height
|
41
|
40
|
39.1
|
38.2
|
37.3
|
36.5
|
35.7
|
34.9
|
34.2
|
33.5
|
32.8
|
32.2
|
31.6
|
31
|
30.4
|
|
|
Width
|
27.5
|
28
|
28.5
|
29
|
29.5
|
30
|
30.5
|
31
|
31.5
|
32
|
32.5
|
33
|
33.5
|
34
|
34.2
|
|
Height
|
29.8
|
29.3
|
28.8
|
28.3
|
27.8
|
27.4
|
26.9
|
26.5
|
26.1
|
25.7
|
25.3
|
24.9
|
24.5
|
24.1
|
24
|