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Call to Action: Voting Open Until December 6th on the Changes Proposed to the 2021 IECC

ICYMI: The code change proposals for the 2021 IECC are open for voting by Governmental Member Voting Representatives (GMVR) from Monday, November 18th through Friday, December 6th, 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.

IECC voting numbers

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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The Making of the 2021 International Energy Conservation Code (IECC)

When I first started working at Steven Winter Associates, I didn’t know that one day I’d find myself involved in the development of codes and standards that impact how our buildings get built. I certainly don’t consider myself an expert, but I have learned a few things the hard way and thought they’d be worth sharing if you might be new to it.

So, here’s my very high-level summary of the code development process with respect to the 2021 International Energy Conservation Code (IECC), aka the “model” energy code. If you are looking for more detail, the ICC webpage has plenty of resources and a more detailed infographic than the one we’re showing and discussing here.

IECC Code Development Process Chart

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Whole Building Blower Door Testing – Big Buildings Passing the Test

The residential energy efficiency industry has been using blower door testing since the mid 1980’s to measure the air tightness of homes. Since then, we’ve evolved from testing single family homes, to testing entire apartment buildings. The Passive House standard requires whole-building testing, as will many local energy codes, along with assembly testing. While the concept of – taking a powerful fan, temporarily mounting it into the door frame of a building, and either pulling air out (depressurize) or pushing air into it (pressurize) – is the same for buildings both large and small, the execution is quite different for the latter.

Commonly called a whole-building blower door test, we use multiple blower doors to create a pressure difference on the exterior surfaces of the entire building. The amount of air moving through the fans is recorded in cubic feet per minute (CFM) along with the pressure difference from inside to out in pascals. Since the amount of air moving through the fans is equal to the amount of air moving through the gaps, cracks, and holes of the building’s enclosure, it is used to determine the buildings air tightness. Taking additional measurements at various pressure differences increases the measurement accuracy and is required in standards that govern infiltration testing. Larger buildings usually test at a higher-pressure difference and express the leakage rate as cubic feet per minute at 75 pascals or CFM75.

Image of SWA staff setting up blower door test

SWA staff at a project site setting up a blower door test

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New York City LL92 and LL94: Sustainable Rooftops

Image of solar panelsAs part of the Climate Mobilization Act, and in accordance with the its greater carbon emissions reduction goals, New York City passed Local Laws 92 and 94 in April 2019, mandating the installation of rooftop solar photovoltaic systems and/or green roofs on buildings across the city. The new requirements will go into effect on November 15, 2019 and will apply to all new buildings and any existing buildings completing a full roof deck or assembly replacement.

The Mayor’s Office estimates that the solar and green roof installations mandated by these bills will result in 300 MW of new solar capacity, 15 million gallons of new stormwater management capacity, 1 million tons of greenhouse gas reductions, and hundreds of green jobs. Based on these projections, this will account for close to 2.5% of the city’s overall emissions reduction goals.*

The laws require that solar and/or a green roof be installed on all available roof space. Areas deemed “not available” and excluded from the requirements include:

  • Areas obstructed by rooftop structures, mechanical equipment, towers, parapets, guardrails, solar thermal systems, cisterns, etc.;
  • Fire access pathways and zoning setbacks;
  • Recreational spaces that are recorded in the Certificate of Occupancy.

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Choosing Insulation for Carbon Value – Why More is Not Always Better Part 1

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.

In the first 30 years of a building’s operational life, 50% of its total carbon emissions are still due to embodied carbon (Source: Architecture 2030)

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