To ensure the shaft is properly supported by structures that are appropriately fire resistance rated, you can either support the shaft at each fire resistant rated floor level or you can utilize an independent structure for the elevator shaft. The former option is conventionally used in situations where your building is a combination of structural steel and concrete with concrete floor assemblies that can be used as part of the shaft fire rating. The latter option is conventionally used in situations where your building utilizes a combustible wood framing system where the floor assemblies cannot be used as part of the shaft fire rating. In wood framed construction, shaft fire ratings and structural support are typically achieved using either a reinforced concrete or concrete masonry shaft. But another option in wood framed construction is to use steel framing that supports gypsum based fire resistant rated shaft-walls. This option is more complicated, but may make sense in some situations.
Apart from the hoistway, there are many other spaces that may require fire resistance ratings. Machine and control room spaces serving the elevator shaft will typically require the same fire resistance rating as the shaft, and will also need to be separated from the shaft with the same fire resistance rating. This also means that any door, duct, other openings or penetrations into theses spaces will also require a fire resistance rated design. Enclosed fire resistance rated elevator lobbies are sometimes required to separate the elevator waiting area from surrounding areas in situations where the elevator connects four or more stories. Many exceptions apply to this requirement, and your design professional should determine if they are necessary.
No floor rating needed
Wood building OK
Good for low rise
Longer installation time
Good for high/low rise
Wood framing NOT OK
Dependent on floor foire rating
Prefabricated structure Wood building OK
Crane install likely
Feasible in few cases
Structure PLUS separate shaftwall required
In buildings with fire suppression systems, conventional machine rooms and control rooms will require fire suppression protection in accordance with NFPA 13. The shaft may also require fire suppression heads, including situations where there are combustible materials such as belts or hydraulic fluids present.
Fire suppression heads in control spaces require another safeguard known as shunt-trip protection. This protection prevents a fire suppression head from drenching live elevator controls with water that might adversely affect the elevator operation. Shunt trip protection involves highly sensitive heat detectors that are installed in the space and detect a fire before the fire suppression heads are initiated. Once the heat detector is initiated, a signal is sent to the shunt-trip breaker that disconnects power to the elevator system before the fire suppression head initiates. This safeguard is geared toward protecting occupants — most likely firefighters — who may still be in the elevator during a fire.
In high rise buildings, building codes often require additional elevator related safety systems to help fire fighters extinguish fires – such as “fire service access elevators” – and systems to help evacuate occupants, such as “occupant evacuation elevators.” These types of elevators have additional requirements that include a specific arrangement of building stairs, standpipe systems, lobbies, fire command centers, and other such spaces to protect occupants and first responders. These requirements have important impacts on the layout and space plan of a building, and should be considered early in the project.
Finally, this brings us to the importance of standby or emergency power requirements in these elevator systems. When firefighters enter a building, one of the first things they may do is disconnect the building power so that electrical hazards do not intensify the fire or endanger those fighting the fire with water based extinguishing methods. However, the firefighters may need the elevators to help battle the fire, and thus they need power to operate the elevator. For small buildings that do not otherwise require standby or emergency power systems, providing this power purely for the elevator systems may come as a surprise. But there are numerous ways to provide this type of power, and some methods are less costly than others. Your design professional can help you select the ideal secondary power source based on the circumstances.
Note: this section is based on the 2017 Ohio Building Code and corresponding reference standards; however, these standards can change from time to time. Make sure to consult with a design professional for the latest codes and standards for your project. This information is intended to be used for general reference only, so be sure to consult with a design professional to determine what’s best for your project.