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Office Projects



Below are some basic design guidelines for initial the core planning of a commercial building.  These guidelines are discussed in further detail in our AIA Continuing Education presentations.


                       Core Planning                                                                 Recommended Applications

   1 Passenger Elevator per 50,000GFA (4,650m²)                  Capacity:  3500-4000lbs. (1600-1800kg)

   1 Passenger Elevator per 2.5 to 3 floors                               Speed:      350-1200fpm (1.75-6.0mps)

   1 Passenger Elevator per 250-300 persons                         Type:         Overhead Gearless, Building Supported MRL


   1 Swing Service Elevator <300,000GFA (91,000m²)            Capacity:   4000-5000lbs. (1800-2000kg)

   1 Dedicated Service Elevator >300,000GFA                         Speed:       350-1000fpm (1.75-5.0mps)

                                                                                                      Type:         Overhead Gearless, Building Supported MRL


Beyond 300,000GFA, contact us for service elevator selection guideance. 

 There are individual project conditions that will affect these guidelines:


  • The anticipated tenancy - single tenant, multi or mixed tenancy - will affect the number of required elevators.


  • Project location - similar projects in New York, the London C.B.D. or Singapore will not be elevated exactly alike as the similar projects in other markets.   


  • Program - today's open, collaborative office environments can increase the office population, placing higher demands on elevators.  Mid-level amenities, such as cafeterias, can create unique traffic demands during peak periods.  And skybridges or below grade parking connections change the arrival and exiting patterns.  We recommend an analysis of these types of designs to determine the proper number of elevators.


  • Projects with express zones, such as those with a retail podium, multiple zones, and/or mixed-use, do not always conform to the typical design guidelines.


  • Corporate facilities have unique amenities and functional requirements which may have higher performance requirements that increase the number of elevators.


  • Core locations - a good design rule is that all work spaces are approximately 150' from the elevator core.  For a larger footprint, i.e. a corporate campus building, maintaining the walking distance may result in multiple cores with more elevators.


Contact us for specific project planning guideance. 

Double Decks
Anchor 3

Double deck elevators are two connected cabs, one above the other, within the same hoistway.  The upper and lower cabs simultaneously serve two adjacent floors.


The advantage of double decks is increased handling capacity and decreased core size.  Analysis typically concludes that double decks reduce the number of required hoistways by approximately 25%, i.e. eight single decks vs. six double decks.  Historically, the disadvantage was termed the "alternate deck loading" experience - during off peaks one cab stops for a call while the other cab's doors do not open.  This experience can be minimized with destination dispatching. 


Double decks require two main lobbies which are typically connected by escalators.  Designers strive to match the main lobby floor heights and the typical level floor heights.  There are "articulating double decks" for uneven floor heights, however, the cost premium encourages designers to work around the fixed floor heights.  


Double decks are used for serving Sky Lobbies as well as local zones.  In Sky Lobby applications, the double decks eliminate the need for oversized single deck capacities that result in awkward cores.  In local zone applications, the required elevator capacity may end up being smaller which results in more rentable area.  

FS² consultants have elevated numerous buildings with the double deck solution.  Examples include Kingdom Tower, Burj Khalifa, Taipei 101, Wilshire Grand, Greenlands Wuhan Tower, Chengdu Greenland Tower, Ping An International Financial Center, Jamsil Lotte Headquarters, and along with many others. 


We welcome the opportunity to visit with you about the advantages of double decks for your project.

Sky Lobbies
Anchor 2

The design of a Sky Lobby (or Lobbies) is a strategy to minimize the building's core space.  Rather than all zones terminating at the Main or Ground level, express elevators move high passenger volumes to an upper level Sky Lobby where persons transfer to local groups.   


Traditionally, Sky Lobbies have been used in buildings above 60 floors.  With the increase in office densities, and the evolution of mixed-use buildings, Sky Lobbies are now more common in lower rise buildings.


Elevating the Sky Lobby requires the determination of the population in the zones above the Sky Lobby, evaluation of the capacity required to meet the Handling Capacity requirement, and analysis calculations to determine the potential level of service.  The elevator group expectations are higher than the performance requirements for the local zones.


Typically, Sky Lobby elevator groups are provided with larger capacity elevators, or are designed as double deck elevators.  Both solutions have unique affects on the architecture.  


FS² has elevated numerous buildings with Sky Lobbies, many of which are shown on our Projects page.

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