Canadian Consulting Engineer

Feature

STGM Head Office

An architect’s head office in Quebec City is the first commercial building in Quebec to earn LEED Platinum certification. Its sophisticated, minimal style is complemented by its innovative and highly efficient energy systems.


STGM head office, Quebec City, rear view. Photo: Stephane Groleau/STGM.

STGM head office, Quebec City, rear view. Photo: Stephane Groleau/STGM.

From the August-September 2016 print issue, page 20.

In the heart of a future eco-district in Quebec City stands an innovative building with many energy efficiency systems, wood materials and natural light. Housing 50 employees of the head office of STGM Architects and its tenant, electrical-mechanical engineering firm Ambioner, the building was completed in 2014 near the intersection Boulevard Ste-Anne and Avenue d’Estimauville. It was the first commercial building in Quebec to earn LEED Platinum certification, which requires water and energy consumption levels respectively 55% and 45% lower than similar buildings that comply with the Model National Energy Code of Canada. STGM were the building’s architects, with Ambioner doing the mechanical-electrical design.
Thanks to the minimalist approach used for its design, the inspiring project required only a $2.7-million investment, with $250,000 dedicated to energy efficiency measures and systems. The 1,000-m2 building has a light wooden structure and a longitudinal shape (13.2 m x 39.75 m, on a north-south axis) that, along with the many windows, skylights and the positioning of openings, favours natural light penetration in 90% of the building and natural transversal ventilation.
We also made sure that construction resources were used responsibly by giving priority to salvaged materials and furniture, wood extracted from durable forests (53%), and recycled, low VOC emission and local materials (37%). A total of 96% of the construction waste was diverted from landfills. The terrain, once occupied by a gas station, was decontaminated.
Not only does this project contribute to the revitalization of the neighbourhood, it also provides an inspiring work environment for the benefit of both our clients and employees. Its two levels include a hall, offices, three conference rooms, library and kitchen area.

Aerothermal and solar technologies
The building distinguishes itself especially by its use of renewable energies and its various energy efficiency systems.
First of all we used a very cost effective and comfortable aerothermal technology. It recuperates heat from outside air by means of high efficiency heat pumps working continuously in accordance with the building needs. The R410a variable refrigerant volume (VRV/VRF) system, composed of pumps with several decentralized evaporator units and a dual condenser, has an installed heat capacity of 84 kW, while its cooling capacity is 94 kW. It favours simultaneous energy transfers from rooms that need air conditioning (for example the server room) to those that need heating. Heating and cooling distribution is ensured by fan coil units linked to a central fresh air system. High induction air diffusers were chosen for most parts of the building, except in the two open work spaces. Besides the rigorously controlled temperature, a good air quality is ensured by CO2 sensors that automatically command appropriate ventilation throughout the different rooms.
The fact that the heat pumps are located in an uninsulated buffer space equipped with glazed garage doors giving onto the outside enables the system to make the best use of climatic conditions: the glass doors facing south are closed during cold days, thus creating a greenhouse effect, and opened in warm weather to allow heat rejection outside. In heating mode, depending on outside temperatures, the system’s coefficient of performance (COP) varies from 2 in cold periods to 4 or 5 in normal operating conditions. Also an enthalpic core heat recovery system (average efficiency of 70%)  reuses residual heat from the building’s stale air, all of which is rejected to the heat pump room.
In addition to this aerothermal system, an 85 kW natural gas boiler is used to provide the few degrees necessary to reach the prescribed COP when deep cold hits in winter, and to heat up the entrances, bathrooms and stairwells. Interesting fact: the boiler only worked three times in the freezing 2014-2015 winter. The boiler might also replace the heat pumps in case of failure.
A 42-m2 solar wall on the building exterior  serves to preheat air in winter. Air is drawn into the plenum space between the building envelope and the solar wall through perforations and then sent to the HVAC system. In total, solar energy provides 1% of all the building’s energy and 24% of its heat.
Other energy efficiency features include the building envelope’s increased insulation, both in the walls (R-31), the roof (R-47) and windows (R-4, 12). LED lighting fixtures (average lighting power of 0.037 W/m2) were used and were linked to individual brightness sensors in the two main open spaces.
The performance of the building is continually monitored by its design team to optimize the systems. The systems were selected to support 200% growth in the two occupying firms while giving the same levels of comfort and, especially, the same energy performance.

Water conservation
Capturing and treating rainwater in order to reuse it the buildings’ bathrooms was not rocket science. “It’s not a major cost and well worth the effort when it comes to saving drinking water, a resource as important to preserve as energy,” says Sonia Veilleux, the design engineer with Ambioner.
The building’s water management system relies on the roof’s 25 m3 retention capacity (the roof has a concave shape with a flow control drain at the centre) and an underground 170-m3 retention tank below the mechanical room.
Thanks to all these features, annual water consumption in the building is reduced to 410,000 L (namely 85,000 toilet flushes) in comparison to a model building of the same type. Speaking of toilets, the plumbing was adapted so that it could accept the most water-efficient devices: sinks and showers have a 5.7 L/min flow, while those of dual flush toilets are 3 and 6 L/flush.
Inspiring work environment
As well as combining high technology and innovative systems, STGM’s building offers a stimulating work environment, and that explains a lot why STGM and Ambioner have a high staff retention rate. Amongst other features, two parking spaces are reserved for carpooling and an electric charging point is available. But the increasing number of people who use alternative means of transportation are pleased with the building’s proximity to public transit system and bike paths, and its safe bike storage. And when employees arrive at work, they are happy to find that 94% of the workspaces have a view to outside, and a terrace with plants and fruit shrubs where they can take their lunch.
“Ultimately, people in the industry will do as we did and make concrete and necessary gestures to attenuate their buildings’ environmental impact,” says Stéphan Langevin, associate architect at STGM. “It’s not that complicated!”

STGM Head Office Project Team
    Client/owner:    STGM Architects
    Architect:     STGM
    Mechanical-electrical     Ambioner (Sonia Veilleux, eng., Rémy Parent, eng., Pascal
    engineers:    Bussières, tech., Christian Nadeau, tech., Jonathan Verreault, eng.)
    Structural Engineering:    Alco
    Civil:    Roche
    Construction:     E Huot
    Landscape:    Les Urbainculteurs
    Photometric study     PhotoLux Design
    and lighting design: