November 19, 2008

BIM software helps predict buildings’ LEED performance

Environmental modelling capacity invaluable for HIP Architects

SAUL CHERNOS

correspondent

On a frigid Alberta morning, when Celsius and Fahrenheit temperatures meet at the bottom of the thermometer, nothing warms Allan Partridge’s heart like Building Information Modeling (BIM).

While architects have long relied on computer-assisted design, BIM software takes a three-dimensional approach, and then some, using building geometry, spatial relationships, geographic data, and quantities and properties of components in order to maximise design, construction, and lifecycle performance.

Partridge, a partner with HIP Architects in Edmonton, has been using BIM software — in his case Autodesk’s Revit — since 2002.

Currently, he’s using it to work out basic plans and necessities during the earliest stages of planning a small office building in the city suburbs.

“When we started, we didn’t have any concept of the architecture, but we knew volumetrically what we needed,” Partridge explained.

“We developed a simple, rudimentary building information model with the sole purpose of informing us about its energy footprint and the way it would be put together. Then, we looked at potential problems. Anybody knows that -40 degree temperatures and wind are not good things in Alberta, so we looked at where problems might occur, using computational fluid dynamics to put together a simple picture. We weren’t trying to be wind engineers — we were just using the tools that BIM allows us, and which you can’t do with CAD.”

Partridge and his staff used BIM to model different scenarios.

They turned the building to face away from the wind, then added factors such as ventilation, looking at the impact in different areas with help from third-party structural analysis and design software. They analyzed the thickness of walls and the thermal abilities of the glass to optimize building envelope performance. As a result, Partridge said, the client had a good idea how his building will perform and how it stands in terms of achieving potential LEED credits, facilitating his pursuit of requests for proposals.

BIM is also proving useful for the Shaw Auditorium at the Mazankowski Alberta Heart Institute in Edmonton. The medical teleconferencing facility, now close to completion, was fabricated in Toronto and assembled on site. Partridge says BIM let multiple parties share information, with the entire building viewable on-screen.

“This demonstrates how we’re going way beyond what CAD could ever do,” Partridge said, adding that building professionals and tradespeople can work alongside each other collaboratively to solve logistical issues such as the location of ductwork or to ensure a timely design and the integrity of contract documents.

Furthermore, he said, BIM can help reduce the number of people needed on site.

In an interview, Partridge said contractors and tradespeople are just beginning to work with BIM software. While the automotive and aerospace sectors have used it for many years, it’s just emerging in the building trades. “Architects have had a robust version for the last seven years, mechanical for the last three years, structural for the last two, and contractors are just this year getting their version.”

Base BIM software providers include Autodesk (Revit), Graphisoft (ArchiCAD) and Bentley Architecture, with additional providers of third-party plug-in software that lets users do scheduling, costing and other tasks. “I use third-party software to do energy analysis,” Partridge said. “All of these plug-ins read the base BIM information in a way that you don’t have that additional step of having to export something.”

Partridge says users ultimately need to embrace changes in design and analysis technology.

“The pitfall is trying to think it’s just 3D software, or AutoCAD or 2D software on steroids. It’s not another form of drafting software.

It’s a massive paradigm shift towards thinking about buildings in the virtual setting. It helps address demand and, at the same time, the growing energy and climate crisis.”

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