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Highlights of interviews made with architects, engineers, and owner representatives
Interview with Russell Fortmeyer, Erin McConahey, Bruce McKinlay, Sam Miller, Regan Potangaroa, and Cristin Whitco, Ove Arup & Partners, Los Angeles, California, September 19, 2001.
Similar responses to previous interview with Maurya McClintock were not duplicated here.
Why do you think there’s a trend now toward high-performance façade systems?
McConahey: There’s an architectural trend toward greater transparency. People want a good visual connection to the outside, but the thermal requirements kills that transparency. With double-facades systems, one can improve thermal performance and gain transparency. For example, the Helicon Building in London involves an all-glass double façade. The façade forms a thermal flue that is 6-8 stories high. Motorized blinds (1.5 ft wide) rotate closure as the sun tracks across the sky – this is centrally controlled using the EMCS system, not the occupant. The U-value and effective SHGC computed with this sun shading system were adequate to meet the requirements of the building in this climate.
McKinlay: Sustainable architecture, with goals of improving connections between indoor and outdoor space and occupant controllability is another factor driving this approach.
Are you able to meet the needs of your client with existing tools?
McConahey: The tools aren’t adequate yet, especially those in the public domain and if, in the case of multi-storey ventilation schemes, thermal links between multiple floors are required. Private domain tools, such as those developed in-house by Arup, are better. Title-24 compliance software doesn’t analyze such things as parallel shading or perforated metal scrims.
How are advanced façade systems implemented in industry?
McConahey: In our recent experience with the Seattle Library, the architect (Koolhaus) developed the design and then convinced the client to accept it before we became involved. The client needs to be made aware that warranties can become a problem when different vendors provide different components of the built-up façade assembly. It’s necessary to determine in advance who will be legally responsible for what. The specifications must carefully delineate who does what and who takes responsibility.
Do you follow-up with post-occupancy evaluations to determine if the façade functions as intended?
McKinlay: This area is evolving. We would like to maintain a continued relationship with the client, but often our scope is limited to designing the building, not conducting post-occupancy evaluations. The LEED program is really driving the increased concern for performance issues through the requirements of commissioning, measurement and verification. This is also consistent with Arup’s interest to evaluate the success of our design, not just the client’s . A shakedown commissioning is required of the contractor after six months. Often it takes two seasons to complete adjust and commission the system properly. A walk-through of the building with the contractor is typically conducted after one year, which is when many warranties expire. Typically, we don’t get feedback from the client unless there is a problem.
Question/Information: eslee@lbl.gov