High-Rise Flashcards
Define high-rise building.
A building with either six or more stories or a building where the highest occupied story/floor is greater than 75’ from the lowest level of fire department vehicle access
In 1976 VA Uniform Statewide Building Code was modified to require what in highrises?
Fire control room
What construction type are most high rise buildings?
Fire resistive construction
What is reflex time?
The time needed to assess the situation upon arrival of the first units, gather info from the annunciator panel, identify and confirm fire floor, proceed to that floor, locate the fire on the floor and prepare to operate.
Residential High Rise Characteristics
Center hallways, numerous interior compartments and 24 hour occupancy
Commercial High Rise Characteristics
center core construction with circuit corridors around the core of the building and may have large, open expanses on each floor. Occupancy loads normally greater during business hours. Elevators, stairwells and mechanical rooms are located in the middle core of the building with offices or residential spaces making up the perimeter of the floor.
What are some concerns of atriums in high rises?
Difficult to control smoke conditions. Typically required to include full sprinkler protection, smoke exhaust systems and smoke curtains.
What may you find in buildings with long hallways?
Fire rated doors throughout the hallways length. If the hallways are sectioned off by fire doors you will typically find a stairwell and standpipe for each area
Pre February 1976 Buildings:
Typically steel and concrete, most are not sprinklered and do not have fire control rooms, modern fire alarms, or elevator control systems.
Features common to older structure include:
- Compartmentalized office and residential spaces with mazelike corridors
- Non-compartmentalized open floor plans for commercial office occupancies
- Presence of window AC units and/or lack of building-wide heating, ventilation and HVAC systems
- Conventional windows that may be opened
- Lack of suspended ceilings (less hidden void space)
- Steel structural members encased in concrete
- Exterior, masonry walls that are tied directly into each floor
- pre- or post-tensioned concrete floors
- reinforced concrete columns
Post February 1976 construction
Fire resistive construction with the following required fire protection features:
- Class III standpipe–2 1/2 in discharges with 1 1/2 reducers
- A compartmentation option existed for buildings built prior to April 91’, however, the vast majority of post 1976 buildings are either partially or fully sprinklered
- Firefighter service to elevators
- HVAC system capable of exhausting smoke
- 2 means of egress per floor
- Fire warning system
- building communications system
- fire control room
- standby and emergency power systems
All occupied high rises in NOVA have (with few rare exceptions):
- At least two approved exits from each floor
- enclosed stairwells
- some type of smoke control system or compartmentation. This includes windows that can be opened, tempered glass panels on at least two sides of the building that can be broken out, or a modified HVAC system that can exhaust smoke to the outside without contaminating other floors
High rise roofs:
may be of much lighter construction that the floors, It may consist of an insulated metal deck roof or be of the same construction as the floors below, but with a weather barrier installed
Each fire station should ensure that preplans exist for the high-rise structures in their area. When possible a copy of this should be placed?
In the fire control room at each building
What is a bulkhead ref highrise buildings?
Bulkhead is when the stairwell extends to the roof in an enclosed entrance way. (looks like shed on roof)
How is roof access obtained?
- hatch
- bulkhead
- penthouse machine room
How are curtain walls attached and how can the contribute to vertical fire spread?
The are mounted to the floor sections or frame of a building (bolted or welded brackets), gaps of 6-12” are common between the floor and exterior wall. Fire stops are required however their effectiveness is questionable. Expect vertical extension through these spaces as well as downward, including the plenum space on the floor below
Intumescent coating?
Spray on fireproofing often used as fire resistive measure for floor/ceiling support systems
Buildings built prior to 1980 may what kind of sprayed on fiber?
asbestos
How much air can low mass concrete (formed concrete) contain?
Up to 20%
How much lighter is formed concrete than traditional concrete?
10-88% lighter
When can failure due to fire occur in light weight concrete?
Failure occurred at 80% of the designed load after 45 minutes of fire exposure. Thermal cracks appear within 14-16 minutes of fire exposure.
Buildings with fixed windows are required to have certain windows that can be broken in the event of an emergency, how are they marked?
Maltese cross or a fire helmet etched in the lower corner of the pane, some may also be opened with special keys or devices
What are windows in highrises made of?
- Plate glass
- Tempered glass
- lexan
Doors leading from the stairwell to the hall, roof or mechanical room may be locked above what floor?
Lobby or first floor
What is a stair door unlock switch, and where is it likely located?
A switch that will simultaneously unlock without unlatching stairway doors, may be in the fire control room
Isolated stairs
Usually have individual entrances and access only one section of the building
Scissor stairs
Independent stairwells on either side of the core. Each stairwell may only serve every other floor.
Accommodation stairs (access, convenience stairs)
Open, unprotected stairways leading from floor to floor within a single occupant’s space
Post 1976 construction should contain what in the stairways
Hard-wired communications linked with the fire control room
What does the presence of a security gate indicated in a stairwell?
The gate denotes the last floor with an exterior entrance
Yard stanchion?
FDC mounted away from the building in the surrounding yard
Hydrants should be found how close to FDC in post 1976 construction?
Generally within 100’ of standpipe and sprinkler FDCs
Pressure-reducing valves should be bypassed for fire department use, how can this be accomplished?
By breaking the “L” shaped arm that restricts the riser wheel
The fact that HVAC ducts at perimeter windows of the building may be fed fresh air from the ducts located in the ceiling of the floor below, allows?
Rapid fire extension
What is a damper? (HVAC systems)
A device controlled by fusible links that limits fire spread through ducts.
In a flat belt design elevator system where is the machinery mounted?
In the elevator shaft and/or on top of the elevator car. Not in the traditional elevator room.
Blind shaft elevators?
Only serves a specific portion of the building and has no openings on other floors.
Define fire control room
A room used for any system in a high-rise where detection, fire protection, air handling systems and communication are centralized for fire department use.