The fixed pane measures 30 inches wide by 60 inches tall. Its bottom edge is 22 inches above the landing surface at the base of the flight, and its nearest edge is 48 inches horizontally from the nosing of the bottom tread. The glass is ordinary annealed and there is no guard in front of it. The large-pane hazardous location criteria include a bottom edge less than 18 inches above the floor, and glazing at the bottom stairway landing is a hazardous location where it is less than 36 inches above the landing and within 60 inches horizontally of the bottom tread. How should the inspector rule?
- AAcceptable: at 12.5 square feet the pane is well over the 9 square foot large-pane threshold, so a pane of that size is exempt from the stairway landing provisions in any case
Size makes a pane a hazardous location; it never exempts one. The large-pane test also fails on its own here, because the bottom edge is 22 inches up and that rule needs an edge below 18 inches.
- A violation: the glass sits 22 inches above the landing, under the 36-inch threshold, and 48 inches from the bottom tread, inside the 60-inch sweep, so safety glazing is required
- CAcceptable: the pane sits a full 48 inches from the bottom tread, and the hazardous zone at a stairway landing reaches only 36 inches horizontally out from the nosing of that tread
Thirty-six inches is the vertical figure in the landing rule, not the horizontal one. Swapping the two dimensions puts the glass outside a zone it is well inside of, at 48 inches against a 60-inch sweep.
- DA violation, but it is corrected by applying an approved adhesive safety film over the face of the existing annealed pane in place of replacing the glass in the opening
Applied film is not the safety glazing the code requires. The provisions call for glazing that meets the impact standard and carries a permanent identifying label, and film is a retrofit product with no standing here.
Why B is correct
Run both tests. Large pane: 12.5 square feet is over 9, but the bottom edge at 22 inches is above the 18-inch trigger, so the criteria are not all met. Bottom stairway landing: 22 inches is less than 36 inches above the landing, and 48 inches is within the 60-inch horizontal sweep from the bottom tread, so both conditions are met and the location is hazardous.
What this question is testing
This item tests whether the candidate evaluates a pane against every applicable hazardous location category rather than stopping at the first one, computes pane area correctly, and distinguishes the 60-inch sweep at a bottom landing from the 36-inch sweep alongside a stairway.
On the job
Windows at the foot of a stair are an architectural favorite and a genuine hazard, because a person falling down a flight arrives at that wall with real energy. Builders order the glass from a schedule that flags doors and tubs but rarely flags stair landings. Measure the two dimensions on site and check the corner of the pane for a permanent bug. If there is none, the glass is annealed no matter what the invoice says, and the correction is a replacement sash.
Memory technique
At the bottom of the stairs, sixty out and thirty-six up.
Exam tip
Glazing questions can trigger on more than one rule. Check every category before you clear a pane.
Where to look it up
IRC Chapter 3, glazing, the hazardous locations subsections covering large panes and glazing at stairways and landings.