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Tag: Sustainable Architecture and Building Magazine

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Mechanical systems for low energy buildings

By Stuart Hood, Principal, Introba 

When it comes to energy use in buildings, it may seem counterintuitive to say that big savings can cost less than small savings – but this is true if you consider the entire building as a single integrated system. Amory Lovins, co-founder of the green energy non-profit Rocky Mountain Institute, has written extensively on the diminishing returns that are realized when an incremental approach is taken to improving the energy efficiency of traditional building systems; and how the whole building approach to energy conservation can ‘tunnel through the cost barrier’. 

A Whole Building Approach

Whether the demand is for heating or cooling, a whole building approach shifts the emphasis from a reliance on high-capacity active systems to the predictable (and much reduced) energy demand inherent in the stable thermal mass of a building with a high-performance envelope. This translates into an enclosure with a greater thickness of thermal insulation, increased airtightness, structural thermal breaks at balconies and other structural penetrations together with careful detailing of cladding systems, doors and windows, and the minimum number of penetrations of ducts and pipes through the building enclosure. 

In addition, adequate solar shading is required on south, west, and east elevations to control heat gain. The shading should be externally mounted with adequate depth if fixed or using manually operable blinds with easily accessible controls through opening tilt and turn windows.

Improving Energy Performance

This whole building approach is the fundamental premise of Passive House design which, rather than using design models to calculate the percentage improvement in energy performance of a building relative to MNECB or ASHRAE standards, sets absolute energy performance targets that must be verified by detailed calculation and air tightness testing during construction, and on completion.

The required maximum thermal energy demand intensity (TEDI) of 15kWh/m2/year for heating and cooling in Passive House buildings is not an arbitrary figure, but rather the threshold at which traditional mechanical systems with perimeter radiators or fan coils are no longer required. With this level of energy demand,  heating and cooling can be delivered through the ventilation system dramatically reducing the size and cost of the mechanical equipment required. At these levels of passive building performance, relatively small electrically powered heat pumps can deliver the much reduced heating and cooling energy required, eliminating the need for high capacity fossil fuel systems.

This has been the approach used in some of the first generation of Passive House buildings completed in Canada over the past 10 years.  The additional upfront cost for the high performance building enclosure described above is more than compensated for by the much lower capital cost of mechanical equipment, and the reduced operating and maintenance costs experienced over the service life of the building.

Building Resilience

However, the prolonged higher temperatures we are experiencing in the summer months (even in traditionally mild climates such as southwest British Columbia) has now made active cooling using heat pumps an imperative in new construction. These heat pumps can be used in tandem with heat recovery (or energy recovery) ventilation systems, to pre-condition incoming ventilation air.  These requirements can be addressed in the design of buildings of different types and scales, but may be implemented in different ways according to building use, occupant density, the nature of ownership  and the building management protocols.

Equipment

Much of the thermal energy required to heat a Passive House or other low energy building comes from the sun but also body heat, lights and appliances, like TV’s and refrigerators. Indoor air quality, including temperature and humidity control and the removal of contaminants is achieved using heat recovery or energy recovery ventilators (HRVs and ERVs).

• An HRV is a ventilation device that helps make buildings healthier, cleaner, and more comfortable by continuously replacing stale indoor air with fresh, filtered  outdoor air. Passive House requires HRVs to be at least 75% efficient, but models with significantly greater efficiency are commonly available. An 85% efficient HRV, exhausting air at 20oC, will provide incoming air at 16oC, when it is -10oC outside.

• An ERV is similar to an HRV but can exchange both heat and moisture. An ERV can provide control over moisture levels in a building during both cold and warm, humid weather. It exchanges moisture between the outgoing and incoming air providing humidification in winter and dehumidification in summer, both of which are beneficial to human comfort, health and energy consumption.

• A heat pump uses electricity to provide both heating and cooling to a building. These appliances are efficient at transferring heat from one place to another, depending on where it’s needed.

In the winter, a heat pump provides heating by extracting heat from outside a building using either the air or the ground as a heat source and moving it inside. In summer, it operates in reverse, to cool the air entering the building.

Stuart Hood is Principal at Introba. Vienna House text written in consultation with Public Architecture + Communication.

Centralized HVAC systems, such as that supplied by Oxygen 8, provides ventilation from a single large ERV, making routine maintenance, including the replacement of filters, much more straight forward. It also reduces the penetrations through the building enclosure, and the length of cold ductwork inside the building envelope that must be highly insulated to mitigate heat loss.

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The drive to decarbonization


The Role of Prefabricated Precast Concrete

By Brian J. Hall and Val Sylaj

Prefabrication, an innovative production method, stands out with its unique features that have the potential to yield significant greenhouse gas (GHG) emission reductions while meeting current and future construction needs. The fundamental differences between factory prefabrication and conventional site construction offer a reduced carbon footprint, and so a promising path towards a more sustainable future.

With traditional construction, the different building materials are delivered from production facilities to the site where the building is constructed from the ground up. In prefabricated construction, building components are fabricated at an off-site facility and installed at the construction site. Moreover, using prefabricated precast concrete products significantly reduces the waste and energy usage typically associated with construction.

This shift from the building assembly stage to the product manufacturing stage not only minimizes the environmental impact but also supports  a more sustainable approach to construction. The benefits of prefabrication are already being seen, and there is potential for further carbon reduction going forward 

Our Progress to Date

Since the publication of our first CPCI industry-average Environmental Product Declarations (EPDs) in 2015, the Canadian precast concrete industry has made significant strides, achieving a remarkable 22% reduction in our A1-A3 (Product Stage) embodied carbon (Figure 1). This reduction underscores our unwavering commitment to sustainability and the potential of prefabricated precast concrete to play a significant part in the decarbonization of the construction industry.

In 2015, ASTM published the first industry average Type III (EPD) for the Canadian precast concrete industry, a significant milestone within the wider construction industry. Since then, the Canadian precast concrete EPDs have been updated twice (in 2019 and 2023) reflecting the more comprehensive emissions data that is now available.

The latest EPDs from 2023 introduced a more detailed regional emissions breakdown than just a national average. Four product categories were reported: architectural precast products, insulated wall panels, structural precast products, and underground precast products.

However, the Architecture, Engineering and Construction (AEC) community must understand the limitations of EPDs and the differences between EPDs and whole life, whole-building life cycle assessment (wbLCA). Most people focus on just the Global Warming Potential (GWP) reported in the EPDs, but what does this number mean? Can you compare two different building materials’ EPDs and make your choice based solely on the lowest GWP?

EPDs are intended to be used as reference input data for consultants conducting a wbLCA, which includes all the life cycle stages identified in European Standard EN 15804, the most popular global standard for producing EPDs for construction products.

For a full ‘Cradle to Cradle’ life cycle assessment, the stages are (Figure 2):

  • Modules A1-A3 Product Stage
  • Modules A4, A5 Construction Stage
  • Modules B1–B7 Use Stage
  • Modules C1–C4 End of Life Stage
  • Module D Net Benefits and Loads   

Brian J Hall, B. B. A., MBA, FCPCI, MRAIC. Managing Director, Canadian Precast/Prestressed Concrete Institute.

Val Sylaj, P.Eng., Ph.D.  President/Director of Technical Services, Canadian Precast/Prestressed Concrete Institute.

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Kipling Transit Hub


Advanced steel framing cuts tonnage costs  

By Scott Norris

Completed in 2022, the Kipling Transit Hub is a 4,890m2 revitalization of an existing transit station. The LEED Gold station serves as a key transit interchange in Toronto’s west end, connecting GO Transit, TTC subway and MiWay buses under one roof.

The focal point of the project was a new 300m2 bus terminal with a long curving cantilevered roof structure projecting out over the bus parking and circulation area. The $73 million design/build project was led by Ellis Don.

The elliptical shaped roof structure supports a 4,460m2 green roof which contributed to the LEED accreditation. Along with the station building there were many other components including a pedestrian bridge, tunnels, platforms and parking, which will not be covered in this article.

Over the course of the project it was determined that the scope of the structural steel work was expanding beyond the initial budget.  At this point, Steelcon was brought on in a design assist role to determine whether its proprietary SIN beam member could be utilized to reduce cost, overall steel tonnage and improve delivery times.

The SIN beam is a custom built-up beam with a corrugated web section that allows the web thickness to be optimized for the design loads.  The sinusoidal (SIN) profile of the corrugations improves the strength-to-weight ratio of the web by virtue of its geometry. This web optimization along with substantial variability in the flange members resulted in significant reduction in the overall tonnage of steel required for the project.

Value Engineering Approach

The initial design for the elliptical roof structure consisted of typical frames spaced at approximately 8.0m on centre through the middle of the structure and transitioning to radially oriented girders at the west end and cantilever trusses to the east. The typical frames consisted of a central truss spanning between columns spaced at 10.5m, with the trusses then projecting 12.75m beyond the supporting columns and tapered down from 2.0m deep at the centre to 300mm at the roof perimeter.  Between the main frames, secondary open web steel joists support a metal deck on which the roof was applied.

During the design assist review, the trusses at the typical interior frames were revised to long span cantilevered SIN girders. In this application the SIN girders were tapered to follow the initial truss profile. The radially oriented girders at the west end of the roof were also replaced with SIN girders. However, the east end remained as trusses due to the efficiency in this configuration.

The final change involved the replacement of all the secondary framing, open web steel joists being replaced with SIN beams. The framing of the associated ancillary buildings and pedestrian bridge was less suitable for SIN beam replacement and was thus not considered. In all a total of 177 open web steel joists and 11 roof truss members were replaced.

Sustainability Approach

Since this project was designed and built before embodied carbon thresholds and other sustainability targets for structural steel projects became common practice, we decided to review the Kipling project to determine the associated benefits of SIN Beam substitution; notably reductions in global warming potential (GWP). The conclusions from this analysis enable us to extrapolate  to future projects which are subject to carbon thresholds.

Scott Norris B.Esc., P.Eng.is Director, Engineering Solutions at  Steelcan. Photos of completed building: Simon Liao, courtesy Strasman Architects.

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Building Better with Steel

Guidelines for lowering GHG emissions in conventional steel structures

By Scott Norris

Finding ways to reduce the carbon footprint of buildings is on every professional’s mind. While certification programs like LEED, Toronto Green Building Standards, and CAGBC Net Zero Carbon Building Standard have helped guide the industry in terms of reducing the environmental impact of buildings, including Global Warming Potential (GWP), it is an ever evolving mission.

The steel industry has begun to take a life cycle approach, reducing the emissions associated with the production of the material, the construction process, as well as the energy efficiency over its lifespan. Regardless of the building type, occupancy, or design material, it is critical that consultants reaffirm their design approaches to ensure they align with this more holistic goal.

In buildings where, large clear spans are required by the program, a steel structure with conventional cast in place concrete foundations is often preferred for reasons of economy.  Steelwork that is efficiently fabricated off-site offers quality-assured, fully tested, and traceable products. On-site construction is fast and has minimal adverse local environmental impacts. These characteristics lend themselves well to warehouses, community centres, transit buildings, data centres and low-rise offices, among others.

For those involved with these building types for which steel is better suited, the overall embodied carbon in the structure can be reduced in several ways:

1. Design efficiently and purposefully. For example:

a. The consultants must work together to determine accurate design loading; excess loading compounds exponentially in the member design phase.

b. Work with the consultants and contractors to understand serviceability requirements of floors, finishes and curtain walls.

c. During preliminary building layout, opt for bays with a 3:4 rectangular aspect ratio for girders to beams. Also, aim for bay sizes of 7.5m x 10m to 10m x 13m to maximize deck spans and optimize framing weight and depth.

d. Utilize efficient framing systems, such as: SIN Beams, composite beams, gerber girder framing, open web steel joists (OWSJs), trusses, arches and tension only members wherever possible.

e. Avoid inefficient systems such as moment frames, transfers of gravity structure, Vierendeel trusses, etc., wherever possible.

f. Understand the transportation impacts created by the materials that you are choosing. Truck transportation produces 17 kg CO2 / tonne / 100 km, while train is 33% of that and marine shipping is 5%.

g. Prioritize members that are produced using an electric arc furnace (EAF). North American manufacturers typically use EAFs to manufacture steel for hot rolled shapes like wide-flange members, angles and channels.

h. Understand the benefits and limitations of hollow structural sections (HSS). These members are more efficient from a material standpoint, however if they are purchased in Canada, they currently come from basic oxygen furnace (BOF) coil which increases embodied carbon and reduces recycled content. If the HSS is purchased from US mills it is more likely that the coil will be coming from EAF.

This will change in coming years when the EAF mills at Algoma Steel and Dofasco come online in 2026.

i. Understand that plate, and cold form steel is often produced in using BOF. This impacts items such as roof deck for example which has high GWP values.

j. Investigate the use of high yield strength for tension members, simply supported columns, beam columns, and simply supported laterally restrained beams

k. Do not forget about the concrete works. Design foundations, slab on grade, floor deck and other elements efficiently and utilize reinforcement only as required Alternately, use fibre reinforcement instead of steel.

l. Work with the concrete suppliers to utilize low carbon mixes.

Scott Norris is Director of Engineering Solutions at Steelcon.

Find out more about carbon neutral steel designs at  www.steelcongoc.com, follow Scott Norris on LinkedIn or contact him directly, snorris@steelcongoc.com.

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UBC AQUATIC CENTRE

Advanced sustainable design strategies improve performance in this challenging building type

Completed In 2017, this 8000m² hybrid competition and community aquatic facility replaces an aging indoor and outdoor pool complex, no longer capable of meeting the University of British Columbia’s changing needs. The challenge was to create a facility that would balance the high-performance training requirements of the university successful competitive swim program, with the increased demand for lessons and leisure opportunities from the rapidly expanding residential communities on campus.

By Jim Taggart

The Aquatic Centre is divided north south into four linear program ‘bars’ – lobby and change rooms, community aquatics, competition aquatics, and bleachers. Daylight is used to differentiate between the two aquatic halls. A line of Y-shaped columns supports a continuous six-metre wide skylight that bisects the aquatic hall, delineating competition and leisure areas. A translucent screen creates a luminescent barrier between the two principal spaces, making it possible to control the uses, and have two different activities or events taking place simultaneously.

The architectural composition consists of three distinct elements: a tessellated standing seam metal roof that hovers over an inclined black concrete base, and is separated from it by a continuous ribbon of fritted glazing. The roof rises and falls according to the functional requirements of the spaces below, its slopes and projections providing rain protection, solar shading, and control of daylight penetration as required. The building has become an integral part of the university’s new student hub, adjacent to the bus loop and a few steps from the new student union building.

As a building type, aquatic centres present some major challenges from the sustainability perspective, including water conservation, air quality, energy optimization, light control and acoustic performance.

Water Conservation

Of these, water conservation is the most significant, standard practice being that pools are emptied and the water discarded every time the pool requires maintenance. For the project team, not only did this seem an outdated practice from an environmental point of view, it also seemed incompatible with UBC’s reputation as a leading proponent of sustainable design.

In fact, water conservation has been an important consideration for the UBC Properties Trust for two decades, with new buildings now required to reduce water consumption by 30% relative to the reference standard. This is part of an overall requirement that all new projects are built to LEED Gold standard.

With the university currently conducting research on regenerative neighbourhoods, the project team began looking for ways in which the building could contribute positively to the infrastructure requirements of the community as a whole.

The answer was to create an underground cistern that could not only collect all the pool water during maintenance, but also supply the fire department should the need arise, or accommodate storm surge water for the north campus precinct, so relieving pressure on the existing storm sewer system.

The cistern, which has a capacity of 900,000 litres, is divided into three compartments according to the amount of filtration required prior to reuse. Another of its functions is to collect rainwater from the roof and the adjacent transit plaza, reusing it for toilet flushing, irrigation and poll top up.

  • PROJECT CREDITS
  • Client  UBC Properties Trust
  • Architects   MJMA & Acton Ostry Architects
  • Photos  Shai Gil; Ema Peter

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Resilience planning for communities to thrive in an unpredictable and changing world

Across Canada, we are witnessing tremendous change, not only in our climate, but also in the urbanization of our cities. As our cities grow, we are experiencing greater pressures on our housing stock and community-wide infrastructure. In an often unpredictable and changing world, resilient design and planning is needed for our cities and communities to endure and thrive in both the short and long-term.

By: Kathy Wardle and Viren Kallianpur

While we must be aware of potential short and long-term shocks and threats facing our communities, as design professionals we have both a responsibility and an opportunity to implement solutions that offer hope to Canadians. This article offers a perspective on resilient design: the guiding principles, best practices, and tools that are available to practitioners today.

There is both commonality and differences in the various Canadian cities in terms of their stressors and threats. With four out of five people in Canada living in cities, the resulting higher density and population in urban areas mean that cities are both agents for climate impacts and solutions.

Growing population through migration and immigration, the rising demand for transportation, and the growing need for infrastructure to provide safety, comfort, and security all combine to create different pressures on our cities.

The global nature of the world we live in also means that stressors and threats faced by other nations have either a direct or an indirect impact on our cities. While global in nature, these impacts need to be resolved at the local level through political will, technical expertise, and individual commitment and responsibility. The effort to find solutions to these issues or problems lie in a more collaborative and collective approach through leadership, community engagement, and collective action.

While climate change is one of the most important drivers for discussions regarding resilience, the conversations should not be limited to climate change; resilience needs to be looked through social, economic, and environmental lenses to identify risks—natural and manmade, acute and chronic—and respond through design and operations planning. Resilience needs to be addressed at multiple levels from a single building, to a district, city and regional level. Policies, strategies, and initiatives at each scale influence the resilience and performance at other scales.

Kathy Wardle, LEED BD+C RELi AP, is Associate Principal, Director of Sustainability, and Viren Kallianpur, AICP, LEED AP BD+C, RELi AP, is Associate, Urban Design Practice, both of Perkins+Will in Vancouver.

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LEED Canada Buildings-in-review: Highlighting LEED®-certified buildings in 2017

MEETING CANADA’S GHG EMISSION REDUCTION TARGETS, ONE BUILDING AT A TIME

Welcome to the eighth edition of the LEED in Canada: Buildings in Review supplement, produced in partnership with SABMag. In this supplement, you will read about some of the most innovative and efficient buildings in Canada. LEED certification provides a critical third-party seal of approval in the marketplace, and ensures that a building has gone through a rigorous process to verify their environmental performance targets.

Continue reading “LEED Canada Buildings-in-review: Highlighting LEED®-certified buildings in 2017”

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