What is the maximum threshold height for an R-3 egress door (non-sliding)?

The correct answer is 1/2 inches because, according to the building codes governing egress doors in R-3 occupancies, any threshold height must not exceed this measurement to ensure compliance with safety and accessibility requirements. A threshold exceeding this height can create a tripping hazard and impede the safe exit of individuals from the dwelling in case of an emergency. The relevant building codes are designed to facilitate smooth transitions and unobstructed paths of egress, particularly in residential settings where the timely evacuation of occupants is critical. Therefore, 1/2 inches is established as the maximum allowable height for thresholds on egress doors in R-3 classifications to maintain safety standards.