Final answer:
Stair handrails should be at least 15 inches away from the wall to provide a comfortable and safe grip while using the stairs.
Step-by-step explanation:
According to building codes, stair handrails should be at least 15 inches away from the wall. This distance ensures that there is enough space for a person to comfortably grip the handrail while ascending or descending the stairs. It also provides enough clearance between the handrail and the wall to prevent any potential accidents or entrapment.