Council on Tall Buildings and Urban Habitat

Calculating Floor Areas in Skyscrapers Workshop
Sunday, 29 October 2017

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SYDNEY – On Sunday, October 29, 2017, delegates gathered for the Calculating Floor Areas in Skyscrapers Workshop, which was held at Rider Levett Bucknall’s office in North Sydney, the day before the CTBUH 2017 Australia Conference. Kindly sponsored/hosted by:

This workshop served as an introduction to the CTBUH research project Creating Industry-Accepted Criteria for Measuring Tall Building Floor Area, which was recently funded by ArcelorMittal. One of the goals of this workshop was to discuss the viewpoints and opinions of various disciplines, and this was reinforced by the group of professionals who attended, which was comprised of designers, elevator consultants, material suppliers, façade consultants, academic researchers, contractors, developers of standards, etc.

Following a short meet-and-greet over coffee and pastries, the workshop began with an introduction from Dario Trabucco, Research Manager, CTBUH, who briefed the delegates on the afternoon’s speakers, introduced the new CTBUH research project, and highlighted some areas where tall buildings could present challenges.

Dario Trabucco, Research Manager, CTBUH, introduces the workshop.

After Trabucco, Peter Stevenson, Founder and President, Stevenson Systems Inc., began his presentation, which focused on the challenges of creating a floor measurement standard, especially one that is accepted internationally. As a member of the Standard Setting Committee (SSC) for the International Property Measurement Standards (IPMS) Coalition, Stevenson was uniquely qualified to speak on the topic, and he discussed some of the debates and issues that have emerged in his time assisting in creating a standard for all buildings. He also discussed how IPMS differed from existing Building Owners and Managers Association (BOMA) standards, and provided some case studies of buildings that his company had measured. He explained that when comparing local standards between different cities, like New York, London, and Singapore, floor area measurement calculations can change by over 25%. Stevenson finished by emphasizing the ultimate goal of IPMS and himself: international consistency on measuring floor area.

Peter Stevenson, Founder and President,  Stevenson Systems Inc., presents on creating a floor measurement standard.
Next, Allen Crawford, Managing Director, Chesterton International, and Vice Chairman of the IPMS Standard Setting Committee, elaborated on Stevenson’s presentation by explaining the conclusions that IPMS had come to in its standards. He explained its three methods of measurement (IMPS-1, 2, and 3) and said that he believes that these standards could represent a “common language” internationally. He explained that these standards have already been adopted by some local governing bodies for property measurement, including that of Dubai.
Allen Crawford, Managing Director, Chesterton International

Jean-Claude Gerardy, Manager, ArcelorMittal, presented next, explaining the impact that conventional structural building materials can have on floor area and their motivation for funding CTBUH in conducting this research. He argued that buildings in countries like Australia – where concrete is currently the primary and cheapest building material – could be more economically feasible if they used steel, due to the increased amount of carpet area and reduced obstruction of exterior views, due to a reduced column size.

Will Miranda, Research Assistant, CTBUH, elaborated on this by showing some case studies of tall buildings and comparing IPMS measurements with the floor area occupied by structural columns. He showed how columns can take up 5 to 10% of the usable floor area, and emphasized that this can be extremely significant when multiplied over 50 to 100 floors in tall buildings. He also showed some common structural technologies used in tall buildings, such as bracing and diagrids, which could present additional issues when measuring floor area.

The presentations concluded with an energetic question and answer session, which continued over another round of coffees.

Delegates participate in a Q&A session.
Next, the delegates gathered again for a roundtable discussion. This discussion was spearheaded by Johannes de Jong, Executive Vice President and Founder, Elevating Studio, and Nick Ferrera, Director, and Harvey James Helou, Assistant Quantity Surveyor/Cost Manager, both of Rider Levett Bucknall. They shared their expertise in elevator consultancy and quantity surveying, respectively, and showed their experiences in how various decisions made by clients and designers can impact floor area calculations.

Johannes de Jong, Executive Vice President and Founder, Elevating Studio, begins the round table discussion. Nick Ferrera, Director, and Harvey James Helou, Assistant Quantity Surveyor/Cost Manager, both of Rider Levett Bucknall, share their experiences.

Following some heated discussions, the group agreed that one of the most important measurements needed for tall buildings is the ratio of carpet area vs. gross floor area (GFA) (GFA is closely associated with IMPS-1 measurements). The group agreed that this ratio could help influence designers and developers to create more innovative buildings by trying to utilize more efficient (smaller) building cores, façades, and structural elements. The group also asserted that there should be case study buildings for comparison, as developers and designers will only strive for innovation in this sense if they can prove they have one of the most efficient buildings, especially when compared to competitors.

The group concluded that CTBUH could move forward by proposing a new measurement standard to the IMPS Standard Setting Committee, which would be closely aligned with carpet area, and by regulating requirements for floor area information submitted on The Skyscraper Center, CTBUH’s database of tall building information. This could lay the foundation for determining what a truly efficient building – in terms of gross floor area vs. carpet area – really is, and what designers should strive for.

Attendees pose for a group photo after the workshop.
Tabitha Stine American Institute of Steel Construction
Jean Claude Gerardy ArcelorMittal
Nicoleta Popa ArcelorMittal
Shelley Finnigan ArcelorMittal
Rishikesh Thacker Arch Realty
Jim Bilger CBRE
Allen Crawford Chesterton Corporate Property Advisors
Will Miranda CTBUH
Dario Trabucco CTBUH
Angela Mejorin CTBUH
Johannes de Jong Elevating Studio
Michiel de Moel Elevating Studio
Stefanie Weidner ILEK University of Stuttgart
Aldo Norsa IUAV University of Venice
Peter Tan Choon Hoo Perunding Kos T & K
Philip Tan Perunding Kos T & K
Nick Ferrara Rider Levett Bucknall
Harvey Helou Rider Levett Bucknall
Win Viriyaprapaikit Sahaviriya Steel Industries PCL.
Peter Stevenson Stevenson Systems, Inc.
Edmundo Klophaus ThyssenKrupp Elevator
William Howell Turner Construction
Kien Cuong Vo Turner Construction
Lester Partridge University of New South Wales