RICHMOND, BRITISH COLUMBIA – Located on the western edge of Richmond’s civic precinct, the 24,240 sq ft (2,254 sq m) Brighouse Fire Hall No. 1 is the flagship of the city’s Fire-Rescue Department. The building, which replaces an older fire hall, is a three-story, state-of-the-art facility targeting LEED Gold Certification and net zero emissions. Serving a region that includes the Vancouver International Airport, the fire hall is comprised of four fire truck apparatus bays and training areas on the ground floor with living quarters on the second story, and administrative offices on the third level.
Because the fire-fighting functions of the building require fire-rated masonry construction, the design team created a stout reinforced concrete shell wrapped in a brick veneer for the first two levels. Resting on top of this plinth, the administrative offices are recessed by balconies on three sides and have a steel frame structure, which accommodates an open window-wall system. To support the roof, six wide-flange steel beams span the length of the structure and cantilever 6 ft (1.8 m) beyond the north side. On the south side, the roof slopes upward and cantilevers 18 ft (5.5 m) to shade a large balcony space.
A cross-laminated timber (CLT) roof deck serves as a structural plate that spans the beams and provides a warm wood finish material for the underside. Composed of dimensional lumber glued in perpendicular layers, CLT is growing in popularity for floor plates, roof decks and shear walls because of its aesthetic appeal and low carbon footprint.
“We saw the fire hall building as a gateway to the public sphere,” says Steve DiPasquale, project lead for Vancouver-based architects, HCMA. “We wanted a dramatic gesture so we designed the cantilevered roof to serve as a marker for the pedestrian route that winds through the civic complex and terminates at City Hall.”
One of the project’s goals was to reduce energy usage by over 50 percent compared with a baseline building as specified by Canada’s Model National Energy Code. Although the building predates British Columbia’s new “Energy Step Code,” it adheres to the code’s mission of achieving net zero by 2032.
The team specified efficient insulation, heat recovery ventilators and an air-to-air heat pump, but energy modeling revealed significant heat loss through steel beams penetrating the envelope.
“We looked at several systems to create a thermal break in the beams including a custom design, but we weren’t getting a big reduction,” says Ian Boyle, a principal structural engineer at Fast + Epp in Vancouver. Boyle proposed using Schöck Isokorb® structural thermal breaks because his firm had used them successfully on projects in much colder climates.
The roof design incorporates 60 Isokorb® steel-to-steel structural thermal breaks to thermally separate the six wide-flange beams on either end, penetrating the building envelope from the interior to the exterior. In addition to reducing heat loss through the steel beams, the Isokorb® system also provides structural support for the long 18 ft (549 cm) and shorter 6 ft (183 cm) cantilevers. Six Isokorb® modules are used on each 18 ft (549 cm) long cantilever and four on each of the 6 ft (183 cm) cantilevers.
Steel-to-steel thermal breaks consist of stainless steel components penetrating R-15 insulation blocks, enabling the necessary structural integrity while reducing heat transfer by up to 75 percent.
“Schöck’s approach is to use stainless steel instead of mild steel threaded rods and bolts,” Boyle says. “Stainless steel is about 70% less thermally conductive than mild steel.” Stainless steel brings the added benefit of resisting corrosion.
Canadian regulations mandate that fire halls serve as post-disaster facilities, which follow specific structural, mechanical and electrical guidelines to ensure that the facility remains functional after events such as earthquakes and other disasters.
“For a post-disaster facility, durability is paramount,” says architect DiPasquale. Cantilevered steel structures such as balconies, canopies or roofs present the danger of introducing moisture into the wall assembly when the warmer moist air condenses on the cooler surface of the steel member. “When a steel beam passes from the interior to the exterior, a thermal break reduces the risk of condensation forming in the middle of the wall assembly,” DiPasquale adds. “The danger in not having a thermal break is that once the assembly starts to fail, water ingress and other moisture related problems can develop.”
The combined goals of disaster resilience and energy efficiency pushed everyone on the project to focus on careful design of the details, according to DiPasquale. “We had to pay attention to the details. The (large) cantilever isn’t your everyday thermal break. We worked closely with our consultants in the planning and design phases, and then made sure the details were executed well in the field.” He adds, “Even if you have a building that’s well insulated, if the details don’t perform, you can really lose efficiency.”
Isokorb® steel-to-steel thermal breaks for canopies
HCMA Architecture + Design
Fast + Epp