From Lithuania to the US: Challenges of Meeting the LBC Window System Requirements

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When designing and building a net-zero building such as the Brock Environmental Center, it was necessary for the project team to consider how each building component affected the goal of achieving the Living Building Challenge (LBC) certification.  Few individual items impacted this goal more than the windows of the exterior façade of the building.

Requirements of the window system

triple glazed window system brock environmental center

Triple-glazed windows with 3 panes of glass

The overall performance of the windows is determined by certain design criteria and performance characteristics.  These requirements include:

  • Triple-glazed windows with 3 panes of glass each separated by a ½“ air space
  • R-Value (insulating capacity) of 6, which is very high for a window system
  • Wood frame with aluminum cladding to reduce the thermal conductivity
  • Category 1 hurricane wind resistant and able to resist the impact of a 2” x 4” shot at the window at 35 mph

Additionally, the vast majority of windows must be of operable casement and awning type. This allows them to be opened during times that the exterior ambient conditions are low humidity and comfortable temperatures—allowing the HVAC system to shut down and save energy to assist with the net-zero energy requirement.

Intus Windows chosen for the Brock Environmental Center

After much research, the choice for the project was Intus Windows, headquartered in Lithuania. Intus is the only window manufacturer capable of guaranteeing that they could meet the R-Value performance and hurricane wind resistance requirements. Their windows are also comprised of 100% FSC Certified wood, which helps to achieve the requirements of the Material Petal. In addition, their R-value rating exceeds industry-leading thermal performance and they can be custom stained to match interior finishes.

Typically, this window system would be disqualified by LBC since the product is manufactured more than 5,000 kilometers from the jobsite; however, LBC waived this requirement since Intus was the only manufacturer in the world that could meet the LBC specifications for overall performance.

Overcoming the challenges of overseas manufacturing

Finding the perfect sustainable window solution wasn’t without its challenges.  The team overcame many difficulties including limitations created by overseas manufacturing—including the tough task of inspecting the fabrication. Photos of the process had to be used in lieu of carrying out the inspections in person.  Furthermore, Intus was required to change its manufacturing process in order to become FSC certified, which allowed them to carry the chain of custody expected by the LBC.

The overseas manufacturing also threatened the construction schedule. The team was challenged with extended shipping and customs durations. The end product was also a very bulky, heavy window system, which resulted in handling and installation becoming a more lengthy process than anticipated. However, a speedy installation corrected any negative impacts to the schedule.

For the most recent schedule updates and upcoming milestones, view this post.

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