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How do building code requirements affect the design and selection of elevators?

 
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Because elevators need to be safe during normal operations and during emergencies, elevator systems and the building construction that supports those systems are tightly regulated by building codes. Some key considerations relate to fire resistance requirements (for shafts, machine spaces, and elevator lobbies), hoistway ventilation requirements, accessibility requirements, foreign equipment restrictions, HVAC requirements, plumbing requirements, fire suppression requirements, emergency firefighter operations, fire alarm requirements, and electrical requirements. Although the building code sections regulating these requirements are extensive and complex, the concepts associated with each of these are discussed briefly as part of this article.
 
 
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FIRE RESISTANCE REQUIREMENTS


Fire resistance requirements apply to elevator systems in most situations. Without safeguards in place, an elevator shaft would function like a chimney in a fire emergency allowing the fire to grow larger and spreading to adjacent floors very quickly. For this reason, a shaft containing an elevator ordinarily needs to be fire resistance rated for one-hour when connecting less than four stories, and ordinarily requires a two-hour rating when connecting four or more stories. In addition, these fire rated shafts need to be supported by surrounding construction that achieves a fire resistance rating equal to or greater than the shaft’s fire resistance rating. For instance, a one hour fire resistance rated shaft will not be effective if the supporting construction burns away in fifteen minutes.

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.

 
 
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FOUNDATION SUPPORTED MASONRY SHAFT

Pros
Average complexity
No floor rating needed
Wood building OK
Good for low rise

Cons
Scaffolds/slip-forom likely
Longer installation time
BUILDING SUPPORTED SHAFT

Pros
Simplest support
Simplest installation
Lowest cost
Good for high/low rise

Cons
Wood framing NOT OK
Dependent on floor foire rating
FOUNDATION SUPPORTED STEEL PLUS SHAFTWALL

Pros
Prefabricated structure Wood building OK

Cons
Great complexity
Steel fireproofing
Crane install likely
Feasible in few cases
Structure PLUS separate shaftwall required
 
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HOISTWAY OPENING PROTECTION


To prevent hoistways openings from aiding the spread of fires or endangering first responders, some buildings may need hoistway opening protection. This type of protection may be required in buildings connecting more than three stories without fire suppression systems, high rise buildings, and in other circumstances. Such protection can be provided by creating fire and smoke rated elevator lobbies at each floor to separate the hoistway openings from the remaining floor areas or by pressurizing the hoistway. Both options have significant cost impacts and creating elevator lobbies will also require aesthetic or experiential considerations.
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ACCESSIBILITY REQUIREMENTS


There are many accessibility requirements in place to allow for the convenient operation of elevators for people with disabilities. Most of these requirements come standard on all elevators, including the placement of braille or tactile call buttons within accessible reach ranges, audible signals used when an elevator arrives, and visual lobby and car lanterns that indicate the car travel direction. In addition to standard accessibility provisions like these, more significant considerations are involved when the elevator is a required portion of the accessible means of egress in a building. Chief among these requirements are two-way communication systems at each landing (within the lobby or waiting area) and a requirement to provide standby power to the elevator system.
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FOREIGN EQUIPMENT RESTRICTIONS


Elevator spaces such as hoistways, control spaces, and machine spaces are not allowed to contain any foreign equipment serving systems other than the elevator, including technology, ductwork, downspouts, electrical pathways, or other building systems unless they are specifically required to serve the elevator system.
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HVAC REQUIREMENTS


With respect to environmental requirements, it is important to keep elevator machine and control systems within the manufacturers designated operating temperature and humidity ranges. Because most controls are microprocessor based nowadays, keeping them cool is key to ensuring efficient and long-lasting performance. And in elevators that require standby power – such as in elevators used as part of an accessible means of egress - these environmental systems also need to be supplied with standby power so that they can continue to operate in an emergency. This often requires small, dedicated HVAC systems to serve the elevator system.
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PLUMBING & FIRE SUPPRESSION REQUIREMENTS


In terms of plumbing requirements, most elevators will require a sump pump in the elevator pit capable of expelling three-thousand gallons per hour for each car in the hoistway. And many regulatory requirements restrict the direct dumping of sump pump ejected water into the building storm or sanitary systems, though sometimes indirect connections to the sanitary system are permitted. The sump pump is another system that must be connected to standby power in accessible elevators.


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.
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ELECTRICAL, FIRE ALARM, & OTHER LIFE SAFETY REQUIREMENTS


Most passenger elevators are required to initiate phase I and phase II emergency operations upon activation of a fire alarm system that restricts use to anyone except first responders. Although these recall functions are technically complex and multi-faceted, a simple description will do for this article. Phase I recall is initiated when the fire alarm system is activated and sends the car to the main level of exit discharge. After the car reaches the discharge level, the doors open automatically, the occupants can escape the building, and the car remains inoperable to the public at the discharge landing with the doors in the open position. The elevator system is also connected to special heat detectors adjacent to the elevator doors at each level, so that if a fire is detected at the level of exit discharge then the elevator will automatically reroute to another level. Phase II recall goes a step further, and allows first responders to manually operate the elevator to move emergency personnel through the building in an emergency.


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.
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SUMMARY


Although elevator systems are sometimes oversimplified as a packaged system, the building code requirements regulating elevator systems have impacts that affect aspects of the building well beyond the hoistway, machine, and control room spaces. If you are considering incorporating an elevator in a new building, adding an elevator into an existing building, or modernizing an existing elevator, then you should work closely with a qualified design professional to assist you with the planning.



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.

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Looking for a broader overview of elevator types, comparisons, and more? Check out Tim’s other whitepaper on elevator basics: