Party Walls

What is a sustainable building? We know it must be an energy-efficient, high-performance building and emit as little carbon as possible to protect the environment. But a sustainable building must also be a healthy building that protects people and communities.

A building can’t be considered sustainable if it doesn’t sustain the physical and mental health of all its intended occupants and sustain the community around it.

Healthy buildings require a holistic approach that accounts for how every building material, system, and technology affects the wellbeing of occupants.

This is an important topic at SWA, so we asked our interns to explore it! They talked to our experienced building systems, sustainability, and Passive House consultants and put together this blog post as a resource on designing and maintaining a healthy built environment.

Keep reading to learn more about the following considerations for healthy buildings:

1. Occupant comfort and productivity
2. Optimal indoor air quality (IAQ)
3. Ventilation system upgrades in existing buildings
4. Healthy building certifications (Fitwel, WELL, etc.)
5. Building operations and maintenance staff training

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We first released this episode in April 2019. Since then, our topic of discussion with Iain has only become more relevant. We recently caught up with Iain and have some updates to share, which are reflected in the resources below and at the end of the episode. Enjoy!

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When you fire on a stove-top burner, whether it is electric, gas, or convection, many byproducts are released. This increase in moisture, gas, and other particulates is not only detrimental to the health of a building, but dangerous for human health as well.

To advance our knowledge on this topic, we invited building scientist and ventilation expert, Dr. Iain Walker, from Lawrence Berkeley National Laboratory (LBNL). Dr. Walker discusses strategies for controlling byproducts associated with cooking by focusing on kitchen ventilation.

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We think a lot about high-performance buildings – but what about the high-performance humans in those buildings?

As the future of office-dwelling is on everyone’s mind, there are a lot of questions surrounding how buildings can help or hinder human health and wellbeing. Tenants may be wondering what questions to ask building owners and building owners may be curious about what steps to take and which of the various healthy building toolkits to employ.

In this episode, Kelly chats with Sarah, Sustainability Director at SWA, about the intersection of health, wellness, and sustainability – or the “triple bottom line” in buildings, and why projects need to take a proactive, holistic approach to all three.

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Passive House design for large multi-family buildings aligns with and builds upon industry guidance for mitigating the spread of infectious diseases.

As the world continues to be turned on its head by the impacts of COVID-19, the building industry has been scrambling to respond, encouraging designers and building operators to learn about how their buildings are being ventilated. Industry experts have produced an array of documents and reports outlining guidelines for reopening buildings safely while minimizing the risk of transferring infectious disease. Much of the focus of this guidance has been on using mechanical ventilation and proper air distribution to dilute contaminant levels in spaces and minimize the spread of viruses. The American Society of Heating, Refrigeration and Air-conditioning Engineers (ASHRAE) has produced a significant amount of guidance for designers. One of their main documents, produced in April, is the “ASHRAE Position Document on Infectious Aerosols,” which provides useful information for how buildings should be designed and operated in response to a pandemic. However, it has prompted questions from design teams about how this might conflict with the goals of very low energy buildings, such as Passive House (PH). This blogpost is written as a response to some of these questions and to highlight the benefits of Passive House design in light of recent recommendations by groups like ASHRAE.

Benefits of Passive House for Mitigating COVID Transmission

The following are some of the benefits of Passive House design for multi-family buildings compared to code requirements as well as some additional guidance for how to design to mitigate virus transmission.

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Imagine this: you’re a chef or cook in a high-stress commercial kitchen setting. You’re making split second decisions with little breathing room, and each quick decision can get you cut or burned. On top of that, you’re in over 100-degree heat, breathing in toxic air from your gas stovetop.

This is an experience Chris Galarza could relate to, from working as a professional chef in various commercial settings. After making the switch to an all-electric kitchen utilizing induction equipment at Chatham University’s Eden Hall campus (the world’s first fully self-sustained university campus), he witnessed the positive difference in the physical and mental health of himself and his staff. He now advocates for electric cooking being a much healthier, safer, cost-effective, and energy-efficient option.

In this episode, Kelly and Chris talk through some electric-kitchen-myth-busting, and ultimately answer the question “is moving away from gas and fire in the kitchen really that radical an idea or does it just make perfect sense?”

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In the post-COVID world, there needs to be a greater awareness that the built environment can protect and promote human and environmental health. Buildings can, and must, play a critical role in delivering a stronger, more resilient public health infrastructure that can help prevent and mitigate crises such as the SARS-CoV-2 pandemic. The good news is that we already have effective tools for designing, constructing, and operating such buildings—chief among them LEED and the WELL Building Standard.

We believe people are now more conscious of how the built environment affects their health. As a result, we’re likely to see an increase in investment in sustainable building design, construction, and operation and a corresponding increase in demand for green building rating systems such as LEED and WELL. We may also see the green and healthy building concepts that are included in these systems increasingly integrated into building codes.

Certification programs (e.g., LEED and WELL) have been developed though collective effort. They are extremely effective and adaptable tools that project teams can use to ensure that their buildings achieve the best possible performance in terms of protecting environmental and human health. Importantly, these programs continue to evolve, offering ever more effective strategies for improving the built environment, ensuring that buildings adapt to whatever circumstances may arise in uncertain times. But right now, project teams can make immediate use of LEED and WELL, and similar tools, to start preparing for the new reality ushered in by the COVID-19 pandemic.

How can project teams leverage LEED now? In this series, we’ve highlighted the LEED credits that can be used to guide efforts to make our buildings safe, healthy, and resilient. (In a follow-up series we’ll discuss the WELL features that can be used to guide our post-COVID building work.)

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As humans, we spend a lot of time indoors. Studies by the U.S. Environmental Protection Agency indicate that under normal circumstances the average American spends over 90% of their life indoors. With the spread of COVID-19 and widespread voluntary and involuntary quarantine, the rise of work from home policies and new direction to social distance has resulted in a further increase to the amount of time we spend indoors. Now more than ever, people are cognizant of the air they’re breathing and the surfaces they’re touching. The buildings that we live, work and play in impact our physical and mental health. With certain building and design considerations, we can make these impacts beneficial.

We recruited some experts at SWA to fill us in on the various considerations when it comes to the health and comfort of a building, as well as some certifications that assure these considerations are met.

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Most of us are familiar with the feeling of a humid apartment after taking a hot shower. Some of us kick on an exhaust fan, perhaps un-fog the bathroom mirror, or even open a window to get the moisture out. Domestic moisture generation—moisture from human activity—is a major factor driving the humidity levels in our residential buildings, especially in super air-tight, Passive House construction. Before diving into just how much of an impact domestic moisture has in our buildings, let’s first look at average daily moisture generation rates of a typical family of three[1]:

• breathing and transpiration—6 to 9 pounds of water vapor/day;
• 10-minute shower in the morning for each individual—3.6 pounds of water vapor;
• cooking fried eggs and bacon for breakfast—0.5 pounds of water vapor;
• cooking steamed vegetables with pasta for dinner—0.5 to 1.0 pounds of water vapor; and
• one small dog and a few plants around the house—0.5 pounds of water vapor/day

This brings the daily total to 11.1 to 14.6 pounds of moisture generation per day, or about 1.5 gallons of liquid water.

Where does all of this moisture go? In a typical code-level apartment building with moderate to high-levels of air leakage, water vapor has two year-round exit pathways: exfiltration through the façade and dedicated kitchen or bathroom mechanical exhaust. Additionally, in the summer, moisture is removed via condensate from the cooling system.

Let’s now put this in the context of a highly energy-efficient apartment with very low levels of air leakage (about 5 to 10 times less than the code-compliant unit), and balanced ventilation with energy recovery. The first means of moisture removal, façade exfiltration, is virtually non-existent given the building’s superior air-tight design. Next is mechanical exhaust ventilation in the kitchens and bathrooms. Because the unit has balanced ventilation and energy recovery, the exhaust air stream in a Passive House project typically passes through the energy recovery core. Depending on the core selection, a large percentage of the interior moisture may be retained in the apartment air despite the constant mechanical air exchange.

There are two basic types of cores:

• Heat recovery ventilator (HRV) in which a certain percentage of sensible heat is recovered (transferred from the exhaust air stream to the supply air stream) while no moisture is recovered.
• Energy recovery ventilator (ERV) in which a certain percentage of sensible heat and a certain percentage of moisture in the air is recovered.

To fully understand this issue, Figure 1 breaks break down the moisture-related pros and cons of ERVs and HRVs in the context of a high-density, Passive House building.

	ERV	HRV
Pros	Summer – prevents high exterior air moisture load from being supplied to interior air; cooling loads are minimized	Winter – flushes high internal moisture load out of building; humidity levels reduced
Cons	Winter – if internal moisture generation is high, interior moisture load is not flushed out of apartment; humidity levels increase	Summer – allows exterior air moisture load to be supplied to interior air: cooling loads increase

Figure 1. Moisture related pros and cons with ERVs and HRVs in high efficiency, airtight construction

 

Traditionally, the key factor in deciding between an ERV or HRV for a high-efficiency building has been the project’s climate. However, as internal moisture loads begin to exceed exterior moisture loads in high-density projects, the decision between ERV or HRV must be looked at more closely for each project regardless of climate.

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Quick pulse survey: in the last three months, since we published our Part I blog on tips for healthier indoor environments, how many of you have either incorporated some of our healthy recommendations into your home, or informed your clients on the most effective ways to address health risks in buildings (hint: if you need a refresher, please visit Part I)?

As previously discussed, there is overwhelming evidence for the business case for healthier buildings, from greater employee productivity and reduced sick days in the workplace to reduced asthma incidents and ER visits for children living in green housing. Leading organizations know that improved wellbeing helps employees to be healthier and lowers healthcare costs. It also helps employees to be more productive, creative and innovative, and less likely to leave for a competitor. The same concept can be applied to tenants in rental buildings and condos.

Before we dive into health tips #6-10, here are some fun (and not so fun) facts to keep in mind while we spend winter days INSIDE our workplaces, schools and homes:

• In the winter, school-aged children ages 11-17 will spend 60 minutes a day outdoors, compared to 175 minutes in the summer. (Source: Schools for Health by the Harvard TH Chan School of Public Health.)
• In a study of 73 elementary schools in Florida, students in schools cooling with the noisiest types of HVAC systems were found to underperform on achievement tests compared with students taking tests in schools with quieter systems.
• According to a recent survey released by the U.S. Green Building Council (USGBC), employees who work in LEED certified green buildings are happier, healthier and more productive than employees in conventional and non-LEED buildings:
  • More than 90 percent of respondents in LEED certified green buildings say they are satisfied on the job and 79 percent say they would choose a job in a LEED certified building over a non-LEED building.
  • More than 80 percent of respondents say that being productive on the job and having access to clean, high-quality indoor air contributes to their overall workplace happiness.
  • 85 percent of employees in LEED certified buildings also say their access to quality outdoor views and natural sunlight boosts their overall productivity and happiness, and 80 percent say the enhanced air quality improves their physical health and comfort.

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You most likely don’t even think about it when using the bathroom. Flip the switch, hear the exhaust fan, and everything is working as it is intended…right? Far too often, the answer is NO, and it is no fault of the user. Sure, homeowners should take a minute each year to vacuum the inside of the exhaust fan housing, but otherwise, these fans should just work. So why don’t they? Hint…it all depends on how it was sized and installed.

Background

The purpose of exhaust ventilation is to remove contaminants (including moisture) that can compromise health, comfort, and durability. Exhaust fans are amongst the simplest mechanical systems in your home, but decades of experience working in homes has shown us that even the easiest things can get screwed up. Far too often, exhaust fans rated for 50 or 80 cubic feet per minute (cfm) of air removal are actually operating at less than 20 cfm. In theory, the exhaust fan should be installed in a suitable location and then ducted to the outside via the most direct path possible. However, the installation of an exhaust fan can involve up to three trades: an electrician typically installs and wires the unit; an HVAC contractor supplies the ductwork; and, the builder/sider/roofer may install the end cap termination. What could go wrong?

As energy efficiency standards and construction techniques have improved over time, new and retrofitted buildings have become more and more air-tight. If not properly addressed, this air-tightness can lead to moisture issues. Quickly removing moisture generated from showers is a key component of any moisture management strategy. While manufacturers have made significant advancements in the performance, durability, and controls of exhaust fans, these improvements can all be side-stepped by a poor installation.

So how do you correct this issue? (more…)