by arslan_ahmed | September 11, 2023 4:00 pm
By Rockford Boyer, B. Arch. Sc., MBSc, BSS
At nearly 10,000,000 km2 (386,1022 mi2) and a maximum temperature ranging from +45 C (113 F) in Yellow Grass, Saskatchewan, to -63 C (-81.4 F) in Snag, Yukon, Canada is one of the largest and coldest countries in the world. However, even with the vast size of the country and the large delta in hot and cold temperatures, the global carbon impact is less than two per cent. In fact, in 2021, the Union of Concerned Scientists listed Canada as having only 1.8 per cent of the total global emissions.
As a point of reference, the U.S. and China account for almost 40 per cent of the total global emissions. It is still very important as Canadians to do their part to further lower the country’s total global emissions. Therefore, it is important to identify key sectors of energy use in Canada and discuss how the construction industry can potentially assist in reducing the impact of carbon generation and air quality through more sustainable building materials and practices.
The total energy demand for Canada was 12,204 PJ (2.92 kcal) with 52 per cent from the industrial sector, 23 per cent from the transportation sector, and 25 per cent from the building sector. The energy demand can be further broken down to 13 per cent residential and 12 per cent commercial. As a point of reference or scale of the yearly Canadian energy use, a petajoule is equivalent to 31.6 million m3 (1 billion cf) of natural gas or 278 million KWh.1 By breaking the petajoule unit down to a more common unit, it is obvious there is a massive amount of energy being consumed in Canada and throughout the world. For the design community, it is important to not only look at the energy/carbon that can be saved in buildings, but also how to reduce the building footprint through manufacturing, transferring, and disposing of building materials.
Considering the environmental impact of insulation materials
All building insulation types save energy throughout the use phase of buildings by minimizing the heat transfer (cold/hot) through the building enclosure. The insulation installed within the building enclosure must be used effectively to have the largest impact on energy reduction. The R-values listed on the data sheet, drum, bag, or from the salesperson are the nominal R-values and do not reflect the actual in-situ effective condition.
Sustainability impact analysis
Typically, calculations are conducted to determine the effective R values of these walls to ensure they meet the local building codes or intended energy use intensity. If all types of insulation produce the same effect R-value when calculated in an assembly, other metrics must be measured to determine the most suitable solution for the building’s carbon footprint. As previously stated, the combined energy demand in Canada for residential and commercial buildings is approximately 25 per cent; therefore, other metrics to assist in determining the most sustainable solution for reducing the overall carbon footprint should be determined by manufacturing and transportation of these insulation types.
Energy demand for manufacturing
Environmental product declarations (EPDs) and life cycle analysis (LCAs) are good tools to help understand the extraction, manufacturing, transportation, and disposal of building materials; however, they do not provide the full story. Building insulation is only a component in the building enclosure and different types of insulation all have different functions and characteristics. For example, fibrous insulation traditionally only functions as a thermal control layer and other components must be used in conjunction with the fibrous insulation to control the air, moisture, and possibly vapour. Spray foam insulation has performance characteristics that can achieve a thermal and air control layer, and possibly a vapour control layer without the need for a secondary material. Therefore, to better understand the total carbon footprint of the building enclosure, a full analysis of all components must be completed to fully grasp the overall sustainability impact.
Transportation’s impact on energy consumption
Energy demand for the manufacturing of thermal insulation is listed in the industrial sector and has the largest total energy demand needs in Canada. At 52 per cent total energy demand, this sector represents the largest opportunity for a reduction in energy use. In relation to the manufacturing of thermal insulation, traditional insulation types such as fibreglass and mineral wool, require fuels such as natural gas and coke to melt the raw materials and spin them into fibres. High performance insulation types such as spray foam, extruded polystyrene (XPS) and expanded polystyrene (EPS) use more electricity to blend or mould their products into shape.
The influence of insulation thickness
In Canada, the benefit of using energy in the form of electricity is that more than 60 per cent of electricity is generated from hydro/tidal sources. Traditional and high-performance insulation types all typically have some percentage of recycled materials in their manufacturing process. The recycling process can include recycling onsite waste and waste directed from landfill created by another source. Mineral wool traditionally receives byproduct from other industrial (pre-consumer) processes, whereas fibreglass and foam insulations traditionally receive their byproduct from the consumer (post-consumer). Some manufacturers of spray foam divert plastic away from the landfill by using hundreds of millions of plastic bottles each year in their manufacturing process.
Canada is a large country. Driving from St. John’s, Newfoundland, to Vancouver, British Columbia, will take one approximately 75 hours with a travel distance of more than 6,700 km (4,164 miles). The increasing number of cars and trucks on the road has increased the vehicle running time due to traffic volume and has had a significant impact on the energy consumed by the transportation sector.
Proper disposal of thermal insulation
With transportation representing 23 per cent of the total energy demand for Canada, the construction industry should not only consider where construction materials are being manufactured, but also the material’s transportation efficiency. Insulation manufacturing facilities are expensive to build and maintain. With limited facilities spread throughout Canada, shipping from the manufacturing location and its shipping efficiency should be considered by the design industry.
Consider the following example, two insulation facilities are manufacturing products in Toronto and an 1,858 m2 (20,000 sf) university project is 2,030 km (1,261 miles) away in Winnipeg which needs to be insulated with R-20 exterior vapour permeable insulation. Shipping efficiency should be considered to minimize the number of trucks needed to provide the required amount of insulation to the construction site. Two suitable options are exterior-grade board stock insulation and site-applied open-cell exterior spray foam insulation. The site-applied spray foam insulation would only require one 16-m (53-ft) tractor trailer to completely insulate this project, whereas the offsite manufactured board stock insulation would require eight tractor trailers (depending on type).
Expanding the perspective on thermal insulation
Thickness of the building enclosure has a direct impact on the total carbon footprint of the building, so ensuring an effective insulation solution will minimize the need for thicker footings, structural members, clips, flashings, jambs, sills, and other structures. Traditional insulation such as fibreglass and mineral wool uses trapped air between the fibres to achieve their R-values. Fibrous insulation typically has an average R-value of R-4 (RSI 0.7) per 25 mm (1 in.). High performing insulations use blowing agents (e.g. hydrofluoroolefin [HFO]) with a higher thermal performance than air to achieve their R-values.
Since 2021, Canada has mandated all blowing agents in thermal insulations must have a global warming potential (GWP) of one. The HFOs in XPS typically have an average R-value of R-5 (0.88) per 25 mm (1 in.), and the HFO’s in closed-cell spray polyurethane foam (SPF) have an average R-value of R-6 (RSI 1.05) per 25 mm (1 in.). It should be noted open-cell SPF does not use any blowing agents to achieve R-3.8 (RSI 0.67) value. EPS uses pentane trapped in closed cells; however, there is still trapped air between the closed cells and the material can still achieve an R-value of 4.7 when using graphite. All these insulations provide valuable resistance to heat transfer; however, they must be used effectively to achieve the best results in the field. Many types of SPF exist, including vapour permeable products used on the exterior.
It appears that more frequent and damaging natural events have been occurring in Canada over the past few decades, whether it is flooding, high damaging winds, ice storms, and/or fires. Using insulation materials that are resilient and have the potential to resist these reoccurring natural events is the key to sustainable design. The Government of Canada states flooding in the country has increased 300 per cent since 1960.2 It also claims two out of 10 homes are at risk of flooding.3 Using closed-cell foam insulation in flood prone regions, as recommended by Federal Emergency Management Agency (FEMA), does not require replacement after a flooding event. Fibrous insulations do, however, as contaminants are trapped within the fibres after the water recedes. Hurricanes hit Canadian shores approximately six times a year and closed-cell SPF has helped buildings survive high winds.4 Adding up to 300 per cent racking strength to the enclosure and providing resistance to wind infiltration, closed-cell SPF acts like a “house glue.”
Further, 2023 has been a terrible year for damaging fires in Canada. Using non-combustible insulation on the exterior has the potential for minimizing the damage to a building in close proximity to a fire. If building materials do not have to be landfilled, manufactured, transported, and installed after a natural disaster, the building’s increased operating carbon footprint has been minimized.
Proper disposal of thermal insulation
There is significant confusion regarding the proper disposal of thermal insulation once it reaches the end of its life. Similar to manufacturing facilities for insulation, recycling plants are scarce in Canada. If the insulation cannot be recycled locally, it may be more environmentally sensible to dispose of it in landfills rather than opting for recycling, especially considering transportation-related carbon emissions as discussed earlier.
Fibrous insulation can theoretically be recycled; however, each manufacturer has its own protocols and would need to be contacted to verify the recycling operations. Foam insulation can be recycled typically in three ways: adhesive pressing, creating polyols, and by energy generated by incinerating. Local reuse may be the best option for fibrous and board stock insulation, which can be used in the construction industry again; however, contaminates will have to be removed prior to reuse. Site applied SPF insulation and the components it adheres to cannot typically be reused in a building as a raw material. Unless there are local insulation recycling facilities, the most carbon friendly solution to discarding insulation is the landfill.
Given its vast size and diverse range of temperatures, Canada is susceptible to experiencing various natural disasters. However, implementing sustainable design and carefully selecting materials can play a crucial role in mitigating the country’s overall global carbon footprint. The industrial sector produces more than 50 per cent of Canada’s total energy demand. Thermal insulation manufacturing and use also impacts the building and transportation sectors; therefore, a designer should choose, analyze, and specify insulations that have the least amount of carbon impact on these sectors.
Embracing a broader perspective
LCAs and EPDs are good tools to assist in determining sustainable insulations; however, calling manufacturers to obtain more information such as type of energy use, facility location, material efficiency, and recycling protocols will ensure the best sustainable design decisions are being made. There is no question that thermal insulation is a requirement for building enclosures.
In the context of designing for the present and future, it is essential to think beyond the conventional boundaries and explore other aspects of thermal insulation that might not have received adequate attention before. This broader perspective allows for more comprehensive and innovative approaches to be adopted. The manufacturing and transportation impacts of the various types of insulation are important considerations in the goal for more energy-efficient design and construction.
1 Refer to the data and analysis by Canada Energy Regulator (CER) on “Provincial and Territorial Energy Profiles–Canada” by visiting www.cer-rec.gc.ca/en/data-analysis/energy-markets/provincial-territorial-energy-profiles/provincial-territorial-energy-profiles-canada.html#s3.
2 Consult the Government of Canada’s “The risk of floods” by visiting www.canada.ca/en/campaign/flood-ready/know-the-risks/risk-floods.html.
3 Read the performance test report rendered to the Spray Polyurethane Foam Alliance (SPFA) “Racking Load Tests”
4 Consult the report titled “Wind Uplift Behavior of Wood Roof Sheathing Panels Retrofitted with Spray-applied Polyurethane Foam” prepared by David O. Prevatt, Ph.D., principal investigator, assistant professor (structures group) for the Department of Civil and Coastal Engineering at the University of Florida. Visit www.yumpu.com/en/document/read/45544489/wind-uplift-behavior-of-wood-roof-sheathing-panels-david-o-.
Rockford Boyer is an experienced building science leader at Elastochem, with more than 20 years of expertise in sustainable building design. He holds an undergraduate degree in civil engineering and architecture, as well as a masters in building science, and is a member of Passive House Canada and the Ontario Building Envelope Council (OBEC). He is also a part-time professor at Sheridan College, where he teaches in the architectural technology program, sharing his knowledge and expertise with future generations of architects and designers.
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