Glazing beside a bottom stair landing lies within the 60-inch horizontal arc, less than 180 degrees from the bottom tread nosing, described in 2021 IRC R308.4.7. Its bottom edge is 24 inches above the landing and its plane is 24 inches behind a guard complying with R312. Assuming no other hazardous-location rule applies, what is the finding?
- The guard exception applies because the glass plane is more than 18 inches from the complying guard
- BIt remains hazardous under R308.4.7 even though the guard exception is satisfied
- CIt is exempt simply because its bottom edge is above 18 inches
- DIt is exempt only if every residential guard is 42 inches high
Where to look it up
https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning
Why A is correct
The stated position initially meets the bottom-landing rule: the glazing is below 36 inches and in the specified arc. R308.4.7 then excepts glazing protected by an R312-compliant guard when the glass plane is more than 18 inches from it. The stated 24-inch separation meets that exception. The 18-inch value is this horizontal guard-to-glass distance, not a bottom-edge height. This finding is limited to this hazardous-location category; it does not exempt unrelated hazards or require tempered glass as the sole safety-glazing product. Source: https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning