9.8.4.6.(1)

Intent 1:

To limit the probability that the top of the nosings of stair treads will not provide sufficient light modeling, which could lead to their location being difficult for the user to see, which could lead to:

• persons falling, or
• persons falling in an emergency, which could lead to delays in the evacuation or movement of persons to a safe place.

This is to limit the probability of harm to persons.

Intent 2:

To limit the probability of:

• excessively wide, sloped or curved portions of treads,
• an insufficient usable tread depth.

This is to limit the probability of:

• persons slipping, tripping or falling, or
• persons slipping, tripping or falling in an emergency, which could lead to delays in the evacuation or movement of persons to a safe place.

This is to limit the probability of harm to persons.

Intent 3:

To limit the probability that a person tripping and falling against the leading edge of a stair tread will be harmed.