High-Rise Building Construction and Compartmentalization Flashcards

In a multi-story high-rise, exit stair enclosures are typically required to have a fire-resistance rating of at least:

Answer: 2 hours

Stair enclosures in buildings four or more stories tall generally need a 2-hour fire-resistance rating.

A door installed in a 2-hour rated wall typically needs a fire-protection rating of:

Answer: 1½ hours

Openings in 2-hour walls are usually protected by 1½-hour rated fire doors.

When smoke is detected in the HVAC system of a high-rise office building, the system is normally designed to:

Answer: Shut down or switch to a smoke-control mode

Duct smoke detectors shut down air handling or start smoke-control sequences so the HVAC does not spread smoke.

Stairwell door locks in NYC high-rise office buildings must release automatically when:

Answer: The fire alarm system is activated

Fail-safe stair door locks release when the fire alarm activates so occupants can re-enter floors from the stairs.

Which feature best limits horizontal fire spread on a single high-rise floor?

Answer: Fire-rated partitions with self-closing doors

Compartmentation with rated walls and self-closing doors keeps fire and smoke within one area of the floor.

Why is stair pressurization used in some high-rise buildings?

Answer: To keep air pressure in the stair higher than the fire floor so smoke stays out

Pressurized stairs push air outward through open doors, keeping smoke out of the exit path.

Concrete floor slabs poured over metal deck in a high-rise serve as:

Answer: A horizontal fire barrier between floors

Rated floor-ceiling assemblies separate floors and slow vertical fire spread when openings are properly sealed.