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Passive House: An Alternative Compliance Path to Toronto Green Standard Tier 3

It is clear to see that the Passive House (PH) standard is here to stay! Across North America, more States, Provinces, and Municipalities are integrating PH into their building standards. One of the more recent adopters is the City of Toronto. In the most recent version of the Toronto Green Standard (TGS), the PH standard is offered as an alternative compliance path to TGS Tier 3, and with this alternative compliance path one obvious question comes to mind: What is the major difference in required component efficiency for a multifamily building in Toronto that is looking to meet either the PH standard or TGS Tier 3?

The PH standard is performance-based and is focused on decreasing whole building energy demand, improving building durability, providing optimal occupant thermal comfort, improving indoor air quality, and reducing carbon emissions. The PH standard reduces building operation costs, decreases carbon emissions, and supports an improved indoor environmental quality for building occupants. The TGS has similar goals and benefits when compared to the PH standard, and there are some obvious synergies in the program design between TGS and PH. The tiered energy category in the TGS takes a similar approach to PH by offering an annual budget for three different categories. For PH you must comply with a total energy budget for annual heating demand, annual cooling demand, and total source energy use intensity. Similarly, but slightly differently, the TGS offers a budget for total site energy use intensity (TEUI), annual heating demand or Thermal Energy Demand Intensity (TEDI), and the additional category of Greenhouse Gas Intensity (GHGI). In both standards, the path to compliance is non-prescriptive and designers can implement a variety of component efficiencies and system options. See table 1 and 2 below:

 

Image of passive house criteria standards

Table 1: Passive House Standard Criteria

Second image of passive house criteria

Table 2: Toronto Green Standard Tier 3 Criteria

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5 New Year’s Resolutions for a High-Performance Year

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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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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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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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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Zero(ish) – Waste Living

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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Become a Carbon Hero with Five Easy Tactics

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.

Integrated Design Process Image 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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Building Energy Performance Standards (BEPS) are Coming to D.C., Are You Ready?

In January of this year, the Clean Energy DC Omnibus Amendment Act of 2018 was signed into law, establishing minimum Building Energy Performance Standards (BEPS) for existing buildings. The law requires all private buildings over 50,000 square feet to benchmark energy use and demonstrate energy performance above a median baseline beginning January 1, 2021. If a building does not score above the median performance, it has five years to demonstrate improvement or face financial penalties.

While quite a few of the details on enforcement are still being worked out, the median scores will be based on 2019 building performance and there are actions you can take today to get ready for BEPS.

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Recent Developments in Off-Shore Wind Energy Production and Renewable Energy Storage

Image of off shore windmills

Block Island Wind Farm, courtesy of the US Department of Energy[1]

Overview

There have been several local and global developments recently with regards to off-shore wind turbines. Advancements in energy storage from both wind and solar energy, coupled with the increased rate of adoption of wind turbines could serve as a major step towards a more renewable-based energy grid and a more sustainable future.

Updates on Energy Production

First, let’s explore some recent news surrounding the adoption of off-shore wind turbines. On a global scale, Scotland’s Hywind project recently proved that technology developed for and by the oil drilling industry can be successfully applied to off-shore wind turbines.[2] The floating 30 MW wind farm, made up of five turbines off the Aberdeenshire coast, has been operational since October 2017. During a three-month period of stormy conditions from November 2018 to January 2019, the wind farm managed to continue energy production at 65% of their maximum capacity. Note that during this period, a North Atlantic hurricane produced swells up to 27 feet! Over the course of a year  “maximum capacity” is approximately 135 GWh of electricity- or enough to power 20,000 Scottish homes. To ensure that the turbines can withstand weather events on that scale, the floating turbines are ballasted by 5,000 tons of iron ore, and 1,323 tons of chain anchor it to the seafloor. This off-shore farm proves that wind turbines can be successfully deployed in deeper waters where it would be increasingly expensive to extend the physical structure of the turbine tower to the seafloor. Additionally, the US, UK, Ireland, Portugal, Spain, France, and South Korea all have started to piggyback off the success of the Hywind farm in various ways. For instance, South Korea partnered with the Equinor, the primary backer of Hywind, to conduct a feasibility study for a 200 MW farm that would be located off the coast of Ulsan.[3][4][5][6]

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Electrify Everything? Part 2.

Heat Pump Water Heaters in Multifamily Buildings

In Electrify Everything? Part 1 that I wrote several months ago, I mentioned that integrated tank heat pump water heaters (HPWHs) can work well in single family homes — even in colder climates. For example, we see quite a few installed successfully in basements in the Northeast. These devices remove heat from the surrounding air, so there needs to be enough heat in the basement air for them to work effectively. During the winter, a home’s space heating system probably needs to work harder to make up for the HPWH. In the summer, the HPWH provides a bit of extra cooling and dehumidification. We put together some guidelines a few years ago on how to get the most from these systems in single family homes.

Image of heat pump

Some places where I’ve seen problems:

  •   Installing a HPWH in a basement closet. Even if a closet has louvered doors, there’s not enough heat/air for a HPWH to work well.
  • HPWHs are relatively loud. If there’s a finished part of the basement (e.g., bedroom or office), the noise can be disruptive.
  • Sometimes there is trivial heat gain to the basement (from outdoors, mechanical equipment, etc.). When a HPWH removes heat from the air, such a basement can quickly become too cold for the water heater to work efficiently (and too cold for comfort if someone uses the basement).

But overall, HPWHs in single family basements can work effectively.

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Five Steps to Get Started with Net Zero Energy Buildings

Net zero buildings are becoming increasingly popular, and some jurisdictions, such as Washington, DC, are projected to become code within the decade. Massachusetts will also begin development of a net zero building code. Curious if your building is a net zero contender or what it would take to reach net zero targets?

What Does it Mean to be Net Zero?

The term “net zero” commonly refers to zero-energy buildings. In simple terms, a zero-energy building is one that produces as much energy as it consumes on an annual basis. There can be nuances and caveats to this definition, but for now, we want to bring you up to speed on five key net zero energy strategies to consider if you’re interested in developing a net zero building.

1. Maximize space for on-site renewable energy.

How tall is your building?

  • Any building over five stories will be challenging, if not impossible, to achieve net zero with on-site renewable energy production alone because building energy demand will likely exceed available site area. Maximize your solar with a smart layout and consider if other renewables, such as geothermal, are possible.

    Image of roof layout

    Typical roof layout for multifamily building, including necessary setbacks for fire access, mechanical equipment access, and shading from bulkheads. Fire access is based on FDNY guidelines.

Do you have other spaces available for solar photovoltaics (PV)?

  • Your development may have a separate parking garage or parking lot on site. These are great places to install a PV system, which can significantly increase the amount of on-site renewable energy production and help make achieving net zero more of a reality.

Do I have to have all renewables on-site to be net zero?

  • If you don’t have enough room for on-site renewables, you can look into purchasing off-site renewable energy options, such as community solar, power purchase agreements, or renewable energy credits.

Now that you’ve considered renewables, let’s move on to net zero building design considerations.

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The Impact of Energy Star’s Portfolio Manager August 2018 Updates on NYC’s Local Law 33 Grades

Image of Letter Grades from SmartBuildings.NYC site

Letter grades are coming!

NYC’s building owners and real estate management firms now have one more thing on their plate to consider: Local Law 33 of 2018. LL33 compliance will assign letter grades to buildings required to benchmark energy and water consumption. The energy efficiency score will relate to the Energy Star Rating earned using the U.S. EPA Energy Star Portfolio Manager (PM).

The law will come into effect on January 1, 2020, and will utilize the previous year energy data to set the energy efficiency score and letter grade as follows:

Picture of Buildings, with quote "Your energy letter grade will be posted in your lobby in 2020. Are you ready?"A – score is equal to or greater than 85;

B – score is equal to or greater than 70 but less than 85;

C – score is equal to or greater than 55 but less than 70;

D – score is less than 55;

F – for buildings that fail to submit required benchmarking information;

N – for buildings exempted from benchmarking or not covered by the Energy Star program.

Why is my letter grade lower than expected?

Property owners should be made aware that if their property earned an energy efficiency score of 75 for the 2018 Benchmarking filing, the new score for the 2019 benchmarking filing may have fallen as much as 20 points. In LL33 terms, what could have been a letter grade “B” could now be “C” or “D” based on PM updates implemented in August 2018. Property owners will want to learn how the Energy Star PM update will affect their LL33 letter grade.

To understand the correlation and impact that the August 26, 2018 Energy Star PM update will have, it is important to look back at what took place as part of that update.

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Replacing Indian Point – An Update

Last year, we wrote about New York State’s plans for replacing the 2,000 megawatts of electricity provided by Indian Point. As of March 2018, Indian Point is still slated to close in April of 2021. The New York State Independent System Operator (NYISO) will reassess the plant’s retirement plan later this year and will continue reassessing this plan regularly to ensure that the state’s electricity needs are met. At the time of the initial closure announcement, the replacement plan leaned heavily on increasing transmission capacity to New York City, particularly via the proposed Champlain Hudson Power Express. However, there were still some gaps between downstate’s power requirements and the total power available without Indian Point.

Indian Point Image

In December 2017, NYISO released an Indian Point retirement assessment report and concluded that downstate’s power requirements will be met, providing that three proposed power plant projects in New York and New Jersey are completed on time. The CPV Valley Energy Center will be a 680 MW natural gas-fueled combined cycle plant in Wawayanda, NY, opening later this year. The Cricket Valley Energy Center will be a 1,100 MW natural gas-fueled power plant in Dover, NY, and is slated to begin power generation in 2020. An additional 120 MW of capacity will be added in Bayonne, NJ. As of the end of 2017, NYISO has determined that all three of these projects must come online by 2021 in order for the Indian Point shutdown to go through.

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Power vs. Energy

I can get worked up about units, and this can really annoy people. It especially annoyed students I taught in grad school. I was pretty tyrannical when grading; they always had to include units in their calculations. They could have all the right numbers, but they didn’t get full credit unless all the units were right too. I have no regrets about being such a stickler, because I see tons of confusion about this in the building & energy fields. So here’s a rant about one of my pet peeves: power and energy.

Question: What’s the difference between Power and Energy?

Is this some kind of philosophical question? A koan to meditate upon? No. There’s a real answer (in the engineering world at least). Power is the rate of energy.

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Replacing Indian Point

 

Under an agreement reached earlier this year between New York state officials and Entergy, the Indian Point Energy Center could be shut down as early as April 2021. The big question going forward is what will replace the 2,000 MW of electricity currently being provided to the downstate region by Indian Point. This energy gap will occur just as New York State is working to meet Governor Cuomo’s goal of having renewable energy account for half of the electricity delivered by utilities in New York by 2030.
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2016 New York Energy Code Blower Door Testing – How Does it Measure Up?

Written by Sunitha Sarveswaran, Energy Engineer

Welcome to part three of the air sealing blog post series! In previous posts, we have reviewed the substantive changes in 2016 New York Residential and Commercial Energy Code, focusing specifically on the new blower door testing requirements. In this blog post, we’ll examine how these requirements stack up in comparison to green building certifications that we are already familiar with: LEED for Homes, LEED BD+C, ENERGY STAR® Certified Homes, ENERGY STAR® Multifamily High-Rise (ES MFHR) and Passive House (PH).

To make this easier to digest, we’ve divided this comparison into two parts – compartmentalization and building envelope. If you need a refresher on the difference between these two types of blower door tests, we recommend referring to the article “Testing Air Leakage in Multifamily Buildings” by SWA alumnus Sean Maxwell.

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Heat Pumps Are Taking Over

Air-source heat pumps are a booming business. In the Northeast, manufacturers report that sales of residential systems have increased by 25-35% per year over the past 5-10 years. We’ve seen more and more systems being installed in existing homes (to provide cooling while offsetting oil or propane used for heating) and into new homes (often as the sole source of heating and cooling).

We’ve looked into these systems often, and from many perspectives. I’m planning a series of posts, but, for now, here are the answers to some basic questions we receive from clients.

First, the basics: What is an air-source heat pump (ASHP)?

It’s an air conditioner that can operate in reverse. During the summer, it moves heat from indoors to outdoors. In the winter, it moves heat from outdoors to indoors. We helped NEEP (the Northeast Energy Efficiency Partnerships) to put together a market assessment and strategy report on ASHPs. The early sections in this document (see p. 12) outline the different terms and types of heat pumps (ducted/ductless, split/packaged, mini-split, multi-split, central, etc.) Unfortunately, different people can use the same term to mean different things, but hopefully the NEEP Northeast/Mid-Atlantic Air-Source Heat Pump Strategies Report can help clarify things.

Indoor section of heat pump.

 

Outdoor section of a heat pump.

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California: Three Hours Behind the East Coast, but Years Ahead in Sustainability?!

Solar Panels San Francisco

Image source: www.greentechgazette.com

As a native Californian, I often marvel at my home state’s progressive attitude towards environmental conservation. In 1988, we were the first state to adopt air quality standards, which the federal Clean Air Act would later be amended to resemble. More recently, landmark legislation such as A.B. 32, or California’s Global Warming Solutions Act of 2006, set the first statewide requirements for GHG emissions reductions in the country. Today, cities like San Francisco have plastic bag bans and zero-waste initiatives. However, our culture is one of sustainability partly out of necessity—in January 2014, Governor Brown declared California’s severe and sustained drought situation a state of emergency. Despite our already resource-constrained present, California’s population is anticipated to increase by 14% over the next fifteen years to 44 million people. The good news is, we’ve made some big strides recently in planning for the future demands of an ever-growing population.

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CT Zero Energy Challenge (Part 2) – An Alphabet Soup of Certifications

Earlier this week, we posted a video about the CT Zero Energy Challenge’s first-place winner, the Benker/Wegner Residence. Today we bring you the story of the third-place winner in this year’s challenge, the Taft School’s Residence. Aside from housing faculty members, the home is serving as a teaching aid for Taft students to study the design details of a high-performance home, and to understand the experience of living in one.

After installation of a 13kW photovoltaic (PV) system, the home achieved a HERS Index of -14! The SWA team is providing certification support for a slew of exciting green building programs including the stringent Passive House US™ Certification, LEED for Homes, Living Building Challenge™, and ENERGY STAR v3.1.

Check out the video featuring the project team members: Architect, Elizabeth DiSalvo from Trillium Architects; Builder, Chris Trolle from BPC Green Builders; and SWA’s Maureen Mahle.

Question? Comment? Submit it below; we would love to hear from you!

SWA High Performance Design Best Practice: Limiting Shelf Angles in Masonry Buildings

BACKGROUND

The multifamily building industry has adopted a best practice long touted by the building science community: continuous insulation at the exterior of the building. However, even in this ideal circumstance in which the insulation is installed flush and without gaps against the exterior substrate (concrete block or sheathing) with an air barrier applied to this substrate beforehand, the overall performance of the insulation will be vastly reduced by the installation of shelf angles.

Shelf angles (also know as relieving angles) are designed to support the expansion and contraction of the brick coursing; however, this presents a direct challenge to the continuity of exterior insulation. Standard design details interrupt the exterior insulation at every shelf angle, typically at every floor in line with window lintels. Since the shelf angle is made of steel, a highly conductive material, this interruption impacts not only the effectiveness of the insulation in general, it provides a considerable thermal bridge over the entire horizontal band of the building at every occurrence.

A recent article by Urban Green Council, “State Energy Code Clarification Will Stem Heat Loss through Walls,” made it clear that a continuous shelf angle has “about the same poor thermal performance as [an] exposed slab edge.” The full article can be read here.

Fig. 1. An infrared (IR) image that shows the thermal impact of shelf angles

Fig. 1. An infrared (IR) image that shows the thermal impact of shelf angles

 

SWA RECOMMENDATION #1: LIMITING SHELF ANGLES

Not all buildings require relieving angles. Building owners, architects, and structural engineers should first ask themselves whether relieving angles are necessary at all for the building being designed. If it is determined that these angles will be necessary, the next question the structural engineer should ask himself is what the minimum frequency necessary is to support the brick course. Generally speaking, buildings do not need one shelf angle per floor—despite this being common practice.

In addition to the aforementioned energy implications involved in specifying shelf angles, there are other benefits to eliminating these steel members when possible. The most obvious impact is on upfront costs. At approximately $25/foot of angle iron (via Union Iron Works), shelf angles for multifamily buildings in New York City can cost tens of thousands of dollars.

Upfront and operating (i.e. energy) costs aside, there is also the embodied energy of the material to consider. Not only does the manufacture of the steel angle contribute to its embodied energy, but also all of the energy used to transport these pieces to the project site. By reducing the need for the production of these angles, the overall energy expended to construct a new building decreases.

One additional consideration for owners is the maintenance required for shelf angles. The introduction of brick lintels creates an inherent and inevitable need for future maintenance. Since the cost of this upkeep is often considerable, owners may wish to use the opportunity to limit shelf angles during design to reduce long-term maintenance costs.

 

SWA RECOMMENDATION #2: OFFSETTING SHELF ANGLES

In addition to limiting their frequency, consider a shelf angle offset to further reduce thermal bridging. One such system that allows for this is manufactured by FERO called FAST (FERO Angle Support Technology).

Fig. 2. Typical FAST TM system detail

Fig. 2. Typical FAST TM system detail

FAST is designed to offset the shelf angle from the structural backing, allowing the insulation and air barrier installations to be more continuous. More information about this product can be found on their website.

SWA welcomes the input of design teams for other possible solutions to achieve a more continuously insulated wall. By accomplishing this, the building will have a truly continuous thermal envelope. As a result, thermal bridging will be eliminated along with the associated energy losses.

Fig.3. An offset shelf angle

Fig.3. An offset shelf angle

 

Fig.4. A wall section with an offset structural shelf angle

Fig.4. A wall section with an offset structural shelf angle

 

CONCLUSION

To implement best building practices, fulfill the continuous insulation requirements of certification programs, and comply with NYC Energy Conservation and Construction Code, SWA recommends limiting the number of shelf angles in the construction of the envelope. This will help limit upfront material and long-term maintenance costs.

SWA also recommends off-setting the shelf angle to reduce the thermal bridging these steel elements create. Fewer shelf angles means that there are less obstacles imposed on exterior insulation, resulting in less thermal bridging. Limiting the impact of shelf angles produces a more robust and insulated envelope that will, in turn, positively impact the energy performance of the building and comfort of its occupants.

SWA would like to thank Robert Murray for his assistance with this article.

Robert J. Murray, P.E., LEED AP, Principal
Murray Engineering, PC
307 Seventh Avenue, Suite 1001
New York, NY 10001
Telephone: 212.741.1102
Email: rmurray@murray-engineering.com

 

REFERENCES

1. Anderson, J., D’Aloisio, J. DeLong, D., Miller-Johnson, R., Oberdorf, K., Ranieri, R., Stine, T., and Weisenberger, G. “Thermal Bridging Solutions: Minimizing Structural Steel’s Impact on Building Envelope Energy Transfer.” American Institute of Steel Construction. Modern Steel Construction, 1 Mar. 2012. Web. <http://msc.aisc.org/globalassets/modern-steel/archives/2012/03/2012v03_thermal_bridging.pdf>.

2. FERO: Engineered Construction Technologies. Product Catalogue. Edmonton: FERO: Engineered Construction Technologies, 2014. Web. <http://www.ferocorp.com/pages/fast/fast.html>

Mandatory Energy Benchmarking.. Coming to a City Near You?

Measurement enables Management; Transparency enables Accountability… The quintessential concepts driving adaptation of mandatory energy benchmarking legislation.

Commercial_Benchmarking_Policy_Matrix (cities) - 8.1.14 (2)

Mandatory energy benchmarking represents a pivotal step towards reforming energy usage in American cities, as it galvanizes populations through collective reduction. Like any immature “innovation”, the practice faces barriers and static hindering widespread adaptation and dissemination into the mainstream.

What factors influence proliferation?

Unique building stock and varied regulatory needs necessitate city-specific reporting plans. Until there is a scaleable model of best-practices, development will continue to be resource and time intensive for administration.

Complexity in execution threatens data integrity and program usefulness. Unintentional errors, difficulty in obtaining information, and unfamiliarity with ENERGY STAR’s Portfolio Manager all weaken database strength. The remedy lies in educating elected reporters. Program handlers must be well versed with the operations and techniques necessary to perform their role effectively.

Stakeholder push-back during implementation deters participation and damages program reputation. Greater visibility of post-retrofit results will dispel doubts of program usefulness, while increased availability of financial incentives will quiet claims of marginalization [under-performers stigmatized as poor living options] and unfair penalization [fining of historic buildings or financially underserved properties].

Notes from Abroad: A SWArrior in Sweden

In October, NESEA awarded SWA’s Heather Nolen with a travel scholarship through the Kate Goldstein Fund for Emerging Professionals (you can read the announcement here). Heather joined four other scholarship recipients for a two week  journey to Denmark and Sweden to explore  innovative sustainability methods being used in their buildings. The following is blog entry written by Heather, describing her experience at a location outside of Stockholm. (This entry was reblogged from NESEA’s blog; you can find the original post here.)

We met with Björn Cederquist who was kind enough to tell us about Hammarby Sjöstad, a new sustainable district, which he is quite proud of.

Stockholm is a growing city, with a population of 1.5 million and a serious lack of housing. The city central is quite developed, outside the city there are the typical suburbs, it is the area between the city proper and the suburbs that Stockholm is looking to develop in a planned, sustainable manner. To meet the city’s housing needs Stockholm plans to construct 8,000 units per year, mind you they have only been building at 5,000 units/year of maximum. This is a large undertaking for the city which is being planned in a thoughtful way.

Despite the need for more units of housing there is a strong tradition in Stockholm of midrise buildings which accounts for the reluctance to build higher. Hammarby Sjöstad is mostly mid-rise with one exception, a single 12 story building.

Located in this prime area between the city and suburbs, Hammarby Sjöstad is located at an old harbor and landfill turned Brownfield site. To convert this piece of land into a residential community public transportation had to be extended, both the subway and train lines. The presence of transit shows a commitment to the area, a feeling of permanence which is required to build the community. 80% of residents commute by public transit.

To meet sustainability goals in a comprehensive way the district aimed to be a healthy place for people to live that stimulates the body and soul with opportunities for exercise, sports and culture. Design began in 1990 to construct an “Environmental and Ecological City District,” which includes 11,000 units housing over 25,000 people; an additional 10,000 are projected to work within this area. In addition to the housing and transit systems, power plants were constructed to provide district heating and cooling, waste removal including organic waste, public water supply and wastewater treatment.

Renewable energy sources, harvesting of energy from the areas wastewater system, burning of waste combustibles along with harvesting energy from the sewage system allow Hammarby Sjöstad to operate their CHP plant free of fossil fuels. Central heat pumps at the district plant operate year round to extract energy which allows for district cooling, planned for 10 years the plant is the largest in the world. The wastewater treatment plant harvests both bio-gas and bio-solids. Bio-gas is used to power buses, taxis and some individual stoves. Bio-solids are used as fertilizer in forest, filling mines and soon to be used for agriculture purposed. Combined with advanced waste collection and energy efficient construction Hammarby Sjöstad is a unique community which is a product of long-term planning and collaboration. Sites underdevelopment are learning from Ham Hammarby Sjöstad to further advance eco-districts for long-term success.

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