F80 High-Rise Building Construction and Compartmentalization 3

Question 1

What is 'stack effect' in a high-rise building?

Accepted Answer

Natural vertical air movement through shafts caused by indoor-outdoor temperature differences

Answer

Stack effect drives air and smoke up or down vertical shafts based on temperature differences between inside and outside.

Question 2

During winter, stack effect in a heated high-rise generally causes smoke in shafts to move:

Accepted Answer

Upward

Answer

Warm indoor air is lighter than cold outside air, so it rises through stairs, elevator hoistways, and other shafts.

Question 3

Why can a return-air plenum above a suspended ceiling be a fire hazard?

Accepted Answer

It can carry smoke and fire to other parts of the floor without being seen

Answer

Ceiling plenums are hidden open spaces that can let smoke and fire spread above the ceiling across compartments.

Question 4

A fire door in a stair enclosure must be kept:

Accepted Answer

Self-closing and latching

Answer

Stair doors must close and latch on their own to keep fire and smoke out of the stair enclosure.

Question 5

A 'fire tower' in older NYC high-rises is best described as:

Accepted Answer

An enclosed stairway entered through an open-air balcony or vented vestibule

Answer

A fire tower is a smokeproof stair enclosure reached through an outside balcony or vestibule so smoke cannot get into the stair.

F80 Practice Test