Party Walls

Building industry professionals have made great strides in reducing operational carbon, but without losing ground, we need to shift our efforts toward building materials and embodied carbon.

The time value of carbon is the notion that reducing carbon emissions now provides a greater benefit than reducing the same amount of emissions in the future. In other words, action today is worth more than tomorrow.

We can envision a future where all building materials have low or zero embodied carbon—even carbon-capturing ingredients—and there is a plan for reusing and recycling materials at the end of a building’s useful life. But how do we get there?

Read on to explore data, resources, and tools available now to help project teams reduce embodied carbon along with operational carbon.

Embodied Carbon: How We Define It

There are several stages in a building’s life. The middle stage is when a building is in use, and it’s all about the operational carbon emissions that result from running—or using—the building. Addressing operational carbon has been critical to reducing greenhouse gas (GHG) emissions, and the building industry has made some progress. But important climate action opportunities are missed by focusing only on the middle stage. (more…)

The Clean Energy DC Omnibus Amendment Act of 2018 was signed into law in 2019, establishing minimum Building Energy Performance Standards (BEPS) for existing buildings. The law requires all private buildings over 50,000 SF to benchmark energy use and demonstrate energy performance above a median baseline beginning January 1, 2021. The law also lowers the threshold for buildings that need to benchmark; buildings between 25,000 and 49,999 SF will need to benchmark energy use beginning in 2021. Buildings between 10,000 and 24,999 square feet will need to benchmark energy use beginning in 2024.

If a building does not score above the median performance of Washington, DC buildings, it has five years to demonstrate improvement or face financial penalties. By definition, 50% of the buildings required to comply with BEPS will fall below the median—even those just a point or two under. (You can download a list of property types and their medians here.) Building owners can use this map from DOEE to check if their building meets the BEPS.

This month, DOEE released the final BEPS compliance rules. These rules cover the different compliance pathways and the documentation required for each pathway.

This blog post was originally published on September 11, 2019. It was updated on November 18, 2021 with new guidance in response to the DOEE’s final BEPS compliance rules. Click here to learn more.

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To meet the goals of the Paris Climate Agreement, we must make decisions that will result in the greatest near-term carbon savings. This means taking into account both embodied carbon—those upfront emissions associated with the extraction, manufacture, transportation, and assembly of building materials—as well as the carbon that’s emitted over the course of the building’s operational phase.

We can build a high-performance building with very low operational emissions, but if its embodied emissions are so high that even if it’s a net-zero energy building (meaning it has net-zero operational energy consumption) it would take decades for the building to reach net-zero carbon (meaning it has net zero whole-building lifetime carbon emissions), we’re not actually helping to solve the critical issue of near-term carbon.

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In Part 1 of this blog post, we highlighted two of the most commonly used insulations in the U.S.– XPS board and closed-cell polyurethane spray foam – and noted that they are produced with blowing agents (HFC-based) that are putting more carbon into the air during construction than they save during building operation for many decades. We left you with a question: if we don’t use these insulations, how can we make up for the loss of the helpful qualities that has made us dependent on them?

Insulation Alternatives

One part of the answer comes from the development of new materials. In Europe over the last decade, Honeywell developed a new blowing agent, a hydro-fluoro olefin (HFO), which claims a global warming potential (GWP) of less than one, which is less than that of carbon dioxide.  First in Europe, and now in the U.S., manufacturers such as Demilec and Carlisle are coming to market with a closed-cell polyurethane spray foam that uses this blowing agent instead of the HFCs that carry a GWP of well over 1,000. These spray foams have a slightly better R-value  than their high-carbon predecessors, and otherwise have the same qualities that make them useful in multiple contexts – air/vapor barrier capability, conformance to irregularities and penetrations, etc.  However, they also have many of the same downsides – high flammability, potential (and not completely understood) off-gassing post-application, and the basic fact that they are petroleum products.

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We took some common New Year resolutions and put our SWA spin on them. This year, make resolutions to improve the built environment in 2020!

 

1. Go on a (Carbon) Diet – diets are difficult, but as with all things, moderation is key. Reducing operational carbon use with super-efficient buildings is only part of the equation. We also need to understand the full Life Cycle of carbon use including building materials and products. Fortunately tools such as EC3 are making these analyses easier to understand; and products, including lower carbon insulation options and lower carbon concrete, are becoming readily available.
2. Quit Smoking – enforcing no smoking policies is one of the best strategies to improve the health of all building occupants. If you do allow smoking, make sure you develop a good fresh air strategy and compartmentalize your units with a good air barrier. And check out more of our strategies for healthy indoor environments.
3. Save More Money – lighting provides a significant area for savings. Sure, LEDs are great, but efficient design also means considering lighting power density (LPD). High efficiency fixtures placed in high concentrations still use a lot of energy and can result in over-lit spaces, which drive up upfront and operating costs. Lower your bills and the harsh glare with a smart lighting design.
4. Travel More – seek out hotels and restaurants that people of all abilities can navigate with ease. Access Earth is an app that tracks the accessibility of public spaces worldwide to help take the guesswork out of accessible accommodations in new locations.
5. Learn a New Skill or Hobby – looking to expand your horizons? Check out SWA Careers and join our team of change-makers to help develop and implement innovative solutions to improve the built environment.

 

 

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ICYMI: The code change proposals for the 2021 IECC are open for voting by Governmental Member Voting Representatives (GMVR) from Monday, November 18^th through Friday, December 6^th, and your vote is instrumental in making buildings consume less energy! [Need a quick refresher on the code process? Check out our blog post here!]

Does your vote even matter?

Overall, there are not actually that many voters on a given proposal. In the energy proposals, last cycle, it ranged from about 200-400 voters per proposal, even though there were a total of 1,247 voters on the Group B codes, which includes the IECC.

 

So a small handful of voters can entirely shape the future of the energy codes that dictate how energy efficient our buildings will be! If history repeats itself, while some online voters tend to align with the Committee, many online voters align their votes with those cast by their fellow ICC voters at the Public Comment Hearings. This happened 81% of the time in 2016. Unlike 2016, in this cycle all the electronic votes cast during the Public Comment Hearings will be rolled into the online vote tally (although those voters can still change their vote).

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In a world where everything seems to be packaged in two layers of plastic, where we are encouraged to constantly discard items to make room for new ones, and where social media drives our desire to consume the newest trends, it can seem impossible to reduce our waste. Living a zero-waste lifestyle seems almost too overwhelming. I find myself wondering, “How can I possibly reduce waste when industries target consumers to do the opposite?” and “Even if I do make changes in my own habits, is it enough to make a difference?”

I struggle with the same paralyzing vastness that Jonathan Chapman mentions throughout his book Emotionally Durable Design. Paralyzing vastness describes the tendency to do nothing when a task seems too large to conquer, instead of taking smaller steps. In the past, the seemingly vast nature of zero-waste living discouraged me from doing anything beyond entry-level recycling, but I realized that minimizing my waste is something worth tackling. Therefore, I will be sharing some ideas for working towards a zero(ish)-waste lifestyle — because going from zero to one hundred, or in this case one hundred to zero can be scary — and I’ll include my experience implementing a few of the ideas myself.

WEEK ONE: Apartment Composting

In blogs and articles that speak on behalf of zero-waste living, the importance of sharing with others and asking for help getting started is most frequently emphasized. For example, my apartment complex does not offer any composting services, but the SWA office does (yay sharing!). For week one, I started composting and designated two small resealable containers — one for food waste, and another for paper towels — that are now living on my kitchen counter. I intended on utilizing these two bins throughout the week, and then bringing them to the office for a dump. If you have the ability to start your own compost bin, that’s great too.

While using paper towels throughout the week, I felt less bad about it knowing that they wouldn’t be going into the landfill, but I developed some questions: If I use the paper towel with cleaning supplies, can it be composted?… Is it worth collecting small bits of food waste when I could just eviscerate them in the garbage disposal?… Are garbage disposals bad for the environment and/or do they affect the energy utilized for wastewater treatment?

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SWA’s Enclosure Group is acutely aware that insulation is the most important single material choice to maximize the enclosure’s thermal resistance over its operational life. Many of us in the building industry believe that, combined with a good continuous air seal, the highest insulation value makes the greenest enclosure, helping to reduce a structure’s carbon footprint and combat climate change. It may come as a surprise, then, that some of the most commonly used insulation materials are so carbon-heavy to manufacture and/or install, that for many decades they wipe away the carbon-energy savings they are supposed to provide.  The following is a detailed discussion of how and why this is, and what the industry is doing to change the equation.

Embodied vs. Operational Carbon

The built environment looms large in the climate picture, because almost 40% of the total carbon put into the planet’s atmosphere each year is attributed to buildings. Over the past 30 years of green building, we have overwhelmingly focused on operational carbon – the carbon that buildings emit as they are being used. Only recently have we begun to focus on embodied carbon – the carbon that goes into constructing buildings, which is typically far greater than the energy saved in the first decades of operation. Changes in energy codes are aimed at operational carbon, and even those organizations and standards that have been at the forefront of promoting sustainable building [LEED, PH] have not been quantifying or limiting embodied carbon, although they bring attention to it.

The Time Value of Carbon

Assuming that a building stands for many decades, or even centuries, its operational carbon will eclipse its embodied carbon over its lifetime, and therefore when the building’s carbon Life Cycle Assessment (LCA) is calculated, operational carbon savings will be more important than embodied carbon saved/spent in the long run. Why does embodied carbon deserve equal weight with operational carbon? Because of the total global carbon emissions from buildings, 28% is pegged to embodied carbon. That’s already a large percentage, but when you consider the near term, the first 30 years of a building’s life, the percentage jumps to about 50%. In effect, every new building is in carbon debt upon completion due to the huge amount of carbon emitted  in order to construct it., And in order for the climate to benefit from the energy savings provided by a well-insulated and sealed enclosure and a high efficiency energy system, the building needs to last and be used for a very long time. The problem is that we may not have 30 years, let alone 60, to pay off that carbon debt.

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Last week, I read a blog post from Connecticut Fund for the Environment President Curt Johnson, and he reaffirmed what I already expected: my next car will likely be an electric vehicle (EV). I currently drive a Toyota Prius hybrid, but when I bought it in 2013, the price to purchase and to operate an EV did not work out, so I chose the Prius, which has very reliably achieved 50 mpg over the last six years.

As an engineer who admittedly knows nothing about cars, I feel like the information out there on EVs is either slightly biased (i.e., published by EV manufacturers) or not transparent enough with the math to convince me. So I set out to create a blog post that was unbiased and transparent. I liked this one from Tom Murphy, an associate professor of physics at the University of California, San Diego, so hopefully I’m making it a bit more user-friendly and applicable to your current/local situation.

I just wanted to know two simple things (and admit to ignoring a long list of other factors that influence the type of car most people will choose to drive):

Number 1: At what gas price is an EV cheaper to drive per mile?

Number 2: While EV tailpipe emissions are zero, is my local electric grid clean enough that it’s a good idea, right NOW? I know my next car will be electric, I just don’t know WHEN the grid will be clean enough that it’s better for the environment for me to switch.

When I began writing this article, I had no idea what the answers would be.

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Before you can really dig deep into the advanced design concepts of embodied carbon analysis and whole building energy modeling, you must first perform some bare minimum prep work. An easy way to get the pre-schematic plan up on its legs quickly is to add qualitative performance measures to the architect’s program study or create an Owners Project Requirements (OPR) document. For this article, “qualitative performance measures” refer to the metrics that express embodied carbon, but can also include operational energy, water, and even healthy materials.

An integrated design process (IDP) anchors the architectural program to performance metrics such as carbon dioxide equivalents (CO²e), Energy Use Intensity (EUI), and zero Energy Performance Index (zEPI). So, by completing the IDP, you’re getting the basic tools to optimize embodied carbon and operational energy use in your design:

1. Target the early phase of the project
2. Prepare a Carbon Hotspot and Simple Box energy analysis to compare carbon sensitivity of different schemes not limited to wall and roof construction, massing, and solar exposure.
3. Schedule a workshop with the design team and owner to discuss findings and recommendations.
4. Establish performance targets such as total Carbon Dioxide equivalents as a basic program requirement.
5. Choose a compliance pathway and verify design with Life Cycle Analysis and a Whole Building Energy model.

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