Final answer:
Spiral stairways should have a minimum headroom clearance of 6 feet 8 inches, which is necessary for safety and comfort, in contrast to past inhumane conditions with much lower headroom.
Step-by-step explanation:
Spiral stairways should have a minimum headroom clearance to ensure safety and comfort for users. According to many building codes, a typical minimum should be 6 feet 8 inches (2.03 meters).
This measurement is taken from the leading edge of the stair tread vertically upwards to the ceiling or any overhead obstruction. Spiral staircases with insufficient headroom can be hazardous and uncomfortable, leading to potential head injuries. This standard ensures that most people can use the stairs without bending or ducking, reducing the risk of accidents.
The provided information mentioning headroom between beams being only 2 feet 7 inches highlights the cramped and inhumane conditions slaves were subjected to, contrasting sharply with modern safety standards in building design.