The window meets the required net clear opening area and both clear dimensions. The finished sill of the openable portion sits 46 inches above the floor, and the grille is fastened with screws that require a screwdriver to remove. What should the inspector cite?
- AOnly the grille, because the sill height limit is waived once the opening delivers the full 5.7 square feet of required clear area
Clear opening area and sill height are independent requirements, and meeting one does not excuse the other. A window can pass the 5.7-square-foot test and still sit too high for a child or a firefighter to use it.
- BNothing, because an escape opening on the first floor is exempt from the sill height limit and from the release requirements
Emergency escape openings are required in every sleeping room regardless of story, and no floor level is exempt from these two rules. A grade-floor opening earns a reduced area allowance, not a waiver of height or operation.
- Both the sill height and the grille, because the sill is above the maximum height and the grille cannot be released without a tool
- DOnly the sill height, because a grille of any form is acceptable so long as the clear opening behind it has been verified as adequate
Bars, grilles and covers are permitted, but the code requires them to release from inside without a key, a tool or special knowledge. Verifying the opening area behind the grille says nothing about whether the grille itself opens.
Why C is correct
The maximum sill height for an emergency escape and rescue opening is 44 inches above the finished floor, measured to the sill of the openable portion, and this window is at 46 inches. The grille is a second, independent violation, because anything covering the opening has to release from inside without keys, tools, special knowledge or unusual force. Both items go on the correction notice.
What this question is testing
The item tests whether the candidate evaluates an escape opening against all of its requirements rather than stopping at the area calculation, and whether the candidate knows the release standard for coverings.
On the job
Owners add grilles after the final inspection far more often than during construction, which is why this shows up on complaint and rental inspections rather than on new work. When it does appear during a permitted remodel, the argument is always the same, that the screws come out fast. They do not come out fast in smoke at three in the morning by a child. Quick-release hardware that satisfies the rule is inexpensive and readily available, so there is no reason to negotiate.
Memory technique
Forty-four inches is about waist high on an adult, which is the tallest sill a child can still climb over.
Exam tip
An escape opening has four tests: area, width, height and sill. Anything covering it has a fifth: release without a tool.
Where to look it up
IRC Chapter 3, Section R310.2.2 for sill height and Section R310.4 for bars, grilles, covers and screens.