Pre-Print? This is still a work in progress; I will continue to update this post over the coming weeks
This piece explores why re-orienting buildings around public health is so important, and it offers areas of opportunity (particularly for indoor air quality via HVAC) for anyone– not just building technologists!–to get started.
Earlier this year (2020), I explored how a “Building Technologist” could impact climate change. My investigation was big picture in nature. I concluded that the biggest impact involves addressing the *interfaces* within the buildings industry.
Interfaces […] span both process (who does what and in what order) and product (design criteria and technical specs). Process interfaces include the relationship between tenant and landlord, interfaces with contractor gatekeepers of various size and expertise, and interfaces for financing (e.g. what data sets to support what anticipated bound of risks). Product interfaces include actual hardware and/or software technical specs, form factor, and translation protocols, environmental vs. introduced interfaces, and the juxtaposition of existing vs. new.
I also pointed out that– beyond just design and construction– we need to focus on the “technics” of our buildings: interior systems like heating, ventilation, and air conditioning (HVAC), lighting, etc.
And I explained that an approach to interfaces necessitates addressing the “black box of distribution and maintenance” for end use systems in our buildings.
To make progress, the black box of distribution & maintenance for end use systems needs MUCH more love regarding (a) awareness, transparency, and sexiness, and (b) operations and maintenance, to deal with split incentive hurdles, contractor gatekeepers, and financing head-scratchers.
At the time, I thought my contribution of most impact was to address the frictions preventing people from upleveling the personal infrastructure in their homes. Although my background is in commercial office buildings, I had a hunch that focusing on the “home” (residential) afforded a tighter loop with human behavior and identity.
And then, the pandemic– which I naively thought may be contained– spread across the world.
This brings us to a new framing of my initial query: What can a Building Technologist do about Public Health?
Buildings for Public Health: Why now?
Our attention is starting to shift to the public health impact of our indoor environments.
Globally, the spread of SARS-CoV-2–the virus that causes COVID-19– is known to occur indoors. Studies show that indoor transmission is the culprit the majority of the time. Consensus so far revolves around 3 modes of transmission: (1) fomite (asynchronous) , (2) large droplet (close contact, synchronous), and (3) aerosol / droplet nuclei (close contact, synchrony TBD). Initially, such transmission occurred in tight indoor public spaces (including “indoor” public transit), and then later (as shelter in place orders went into effect) at home. I won’t go into the details here, but look up scientists Linsey Marr and Shelly Miller for more context. TLDR: Avoid underventilated spaces.
What this has proven to me over the past several months: We need to rethink how buildings impact our personal and public health.
Whether residential or commercial, the buildings we inhabit and work in create the basis of our health experience. Spend time at a school with low levels of fresh air (i.e. high levels of CO2)? Studies have shown that this impacts cognition. Live in a building near a highway with poor filtration? Outdoor air pollution can become indoor air pollution. Work after hours in a premium skyscraper? If the building relies on mechanical ventilation, and the system isn’t operating after hours– you’re likely not getting the fresh, clean air you think you are.
These scenarios highlight our “normal” existence. What about in times of virus surge? This pandemic is making it abundantly clear: our buildings are critical to keeping us safe and healthy. But in the past (and by “past” I mean as late as 2019), advocating for implementing systems to provide a healthy, more productive indoor environment was often met by skepticism. Evidence is scarce; a “healthy” building is hard to quantify in operation. Investment impacts don’t seem direct but instead obscure and too far past the horizon. But this pandemic has shown us that our indoor environments DO impact our health, both short and long term. And, we currently lack the ability to (1) “tune” our indoor building conditions to serve as the preventative defense we need, and (2) to then communicate status back to the true users of buildings: occupants.
Across the world, we have receded from public spaces for the seclusion of home– like oysters closing their shells in times of danger. But what does this mean for a future when we begin to return to shared spaces? This is where I’ll focus today’s conversation– on commercial buildings, particularly commercial office. Although remember, the same needs apply to other commercial, residential, and governmental buildings as well.
So, what are healthy buildings?
A lot of my thinking has been encouraged by Joseph Allen & John Macomber’s recent book: Healthy Buildings. (I’ll sometimes refer to it as “HB” in this piece.) They list nine foundations to a healthy building:
Allen & Macomber also superbly describe WHY healthy buildings matter. As a quick summary, they write:
Our central thesis in this book is not only that employee performance drives the bottom line but also that the building (or indoor environment) plays a vital role in optimizing that human performance, and that this building performance has been mismeasured to date.
Now we *can* [emphasis mine] objectively quantify how an investment in the building is an investment in the company. Healthy Buildings improve human performance. Better human performance improves business performance.
In this piece I’ll focus my discussion on the contribution of HVAC to healthy buildings. (Yes, we shouldn’t act in siloes, but we do need a place to start.) Specifically, I’ll cover the following building functions:
- Thermal Health
- Indoor Air Quality
I’ll focus on healthy buildings for general operations (i.e. for business continuity) but then at the end show how these functions can *also* support personal and public health during times of virus surge.
Understanding the problem space
I also recommend Chapter 3 of Healthy Buildings for an excellent survey:
To really understand how this works, it’s worth stepping back for a minute to look at all of the stakeholders involved in the decision-making process around buildings. The motivations are complex, but the lack of market response comes down to four factors: information, inertia, incumbents, and incentives.
The TLDR of the problem space: The buildings industry is full of complicated information flows, misaligned (split) incentives, path dependency, and entangled systems that are not easily nor uniquely configurable. This describes both the industry as a whole AND the complexity contained within each building. Keep this landscape in mind as we dig into various building components.
What is HVAC?
Ahhh, HVAC. What a confusing term.
HVAC stands for heating, ventilation, and air conditioning. When we say “HVAC” we most often mean the TECHNOLOGICAL SYSTEMS that deliver heating, ventilation, and air conditioning in a building. Most commonly, a single HVAC system delivers all three of these functions. Here, we’ll further compartmentalize what an HVAC system really does:
- Manage ventilation
- Manage sensible loads
- Manage latent loads
- Manage distribution across a space
HVAC is really about managing the experience of “air” as a medium. Is that air healthy and comfortable, and is it where it needs to be?
If you already know the basics of HVAC I’ll spare you, but you can learn more about HVAC systems in this separate post.
Healthy Building Opportunities: Ventilation, Thermal Health, and Indoor Air Quality
How can we use the existing functions of a building to deliver greater public health?
Note: In most cases, the actions listed below are the responsibility of the Building Manager (who answers to the Building Owner). If you are a tenant or occupant, you should consider demanding this of your Building Owner.
Ventilation is the management of fresh, clean air. As mentioned above, studies have shown that ventilation rates impact human cognition and productivity. While there are clear design standards, set by ASHRAE, for how much fresh air should be delivered to each space, the industry does not have operating standards for ventilation. (And the standards that *do* exist? Those are just minimum acceptable standards!) Why the gap in design vs. operation? As always, there are many reasons for this breakdown from design to maintenance. Some include: misalignment during the construction and commissioning phase, lost information (either at project start or during operator handoff), and general entropy of operations.
What to do?
- Increase ventilation rates as the system allows (and as a pre-step confirm that rates are even specified!)
- Increasing ventilation rates involves increasing fan speeds, opening fresh air dampers, reducing recirculation
- HB recommends at least 30 cfm per person (design minimum for an office environment is 20 cfm per person)
- Extend operating hours, and/or ensure operations during any occupancy rather than pre-defined building hours
- Ensure that the building is providing healthy ventilation when occupants are in the building
- Refer to HB for greater discussion on extended operating hours
- Implement real time monitoring: carbon dioxide (CO2)
- Monitoring helps building stakeholders understand the current “status” of their indoor environment. HVAC systems will vary whether they monitor CO2.
- Systems with demand controlled ventilation (known as DCV and uses CO2 as a proxy for the number of people present) will typically have CO2 monitoring. Others may require the installation of additional sensors.
Thermal Health (a phrase I took from HB, I prefer it over the industry term “thermal comfort”) is the delivery of safe and preferred temperature. (The word “temperature” here is quite loaded, as a lot of factors actually go into thermal health; check out UC Berkeley’s Center for the Built Environment for more.) Thermal health has also been shown to impact occupant productivity.
What to do?
- Enable “hyper personalized” thermal health (to quote HB)
- Consider tools that allow occupants to personalize temperature and relative humidity to their desired preferences, rather than the rules of thumb set by ASHRAE.
- Enable “hyper localized” thermal health (to quote HB)
- Consider HVAC configurations that allow zone-level control. The most granular systems with today’s technology localize at the room level.
- Implement real time monitoring: temperature & relative humidity (RH)
- Similar to CO2 monitoring, temperature and relative humidity monitoring helps building stakeholders understand the current “status” of their indoor environment. This data can then be used to prioritize upgrades and allows occupants to understand which spaces meet their desired thermal health levels
Indoor Air Quality
Whereas ventilation and thermal health are tuned along a continuum, indoor air quality today is addressed at a binary level. This is partially due to the fact that our control mechanisms for IAQ today (beyond ventilation) center on the use of filters. They are either installed with a certain level of efficiency, or they’re not.
|Sense||CO2, PM2.5, VOC|
|Control||CO2: dial– ventilation (future: carbon sequestration?)
PM2.5: on/off– filters with X% efficiency rating
VOC: dial– ventilation & on/off– filters with X% efficiency rating
|Source prevention||PM2.5: Improve outdoor air quality, Reduce mold & dust
VOC: Avoid high VOC emitting materials
Building automation company Siemens offers a good overview of target ranges and how these conditions can be controlled:
What to do?
- Maintain high quality filters.
- MERV 8 filters are standard, but choose better quality filters such as MERV 13
- Refer to HB for greater discussion on operational impacts of filters
- Implement real time monitoring: fine particulate matter (PM2.5) & volatile organic compounds (VOC)
- Similar to CO2 monitoring, indoor air quality monitoring for PM2.5 and VOCs helps building stakeholders understand the current “status” of their indoor environment. This data can then be used to prioritize upgrades and allows occupants to understand which spaces meet their desired levels. Monitoring can also be used to alert occupants during a high level event
- HB also advocates for regular industrial hygiene sampling
There are many more functions that contribute to Healthy Buildings, such as lighting control, noise control, or fire safety and access control. Another key function of a healthy building is the occupant’s psychological safety. Does she feel safe in the building? (Did she feel the building was healthy enough to even enter?) To build trust with her building, the occupant should be able to review and verify the healthy building measures described above.
Psychological safety also includes feeling “oriented” and “in control.” For example, understanding where critical points of interest can be found, such as through indoor maps and search, is one way occupants can feel a greater sense of safety.
Buildings can deliver public health not just through the existence of the functions I explained above, but also through the interaction of those systems and data with building stakeholders. Specifically, I’m referring to three key forms:
- Control: hyper local, hyper personalized control
- Data (and Transparency): metrics dashboards and location-based data between Building Owners <> Tenants <> Occupants
- Configurability: ability to easily adapt a specific space for different use cases
Hyper local, Hyper Personalized Control
In the building automation world we talk of controllers and actuators. At the HVAC level, this refers to the control and actuation of dampers. These days, “control” is given to the building automation system and control logic is executed behind the scenes once certain environmental conditions (setpoints) are met.
Increasingly, zone level control is becoming important. But what is the compass of a zone? Is it a room? More than one rooms? More granular than a room? Today– the room is the most granular of control areas. Can the room designate its own preferred ventilation rate and pressurization, as well as sensible and latent loads? Or, is the system designed to provide the entire floor (or entire building) the same output? Zone-level control offers greater flexibility and configurability in the long run. (This comes, of course, with the assumption that the systemic whole has the capacity to support such granular configurability. There will be limits– so it’s important to keep the limiting factor in mind.)
In addition to zone level control (hyper local), what about providing more control to the occupant, the person the HVAC is there to serve? Hyper personalized control would match occupants’ preferences in real time. And not just for temperature– as already exists today– but for other IAQ conditions like ventilation.
From a control perspective, tools that connect occupants directly with building systems can serve as a mechanism for public health.
building Health Data (and Transparency)
In the building energy efficiency world, energy use dashboards became a tool used by Building Owners to verify to Tenants that they were making sufficient investments in green buildings. So what will be the equivalent for health metrics, such as location based ventilation setpoints or PM2.5 levels? Can tenants be more empowered, once they understand occupant-impacting building faults before even the systems operator can inform them?
And what about location-based data for occupants? Think about your own experience in re-entering shared spaces / buildings. Before you enter a space, wouldn’t you want to know what its current indoor air quality is? What about after a virus surge– How do you, as an occupant, evaluate whether you feel comfortable to return?
To turn to residential for a moment– I wonder if in the near future we’ll be able to look up on Zillow (or comparable source) not just whether a home has “Heating” or “Cooling,” but whether the building has the capacity to steward healthy levels of indoor air quality.
Too often, “configurability” in the context of buildings and architecture is thought of as the ability to move around walls. The Murphy bed of surfaces, I think. But configurability should extend to the flexibility of the indoor experience as well. That includes the ventilation, thermal health, and indoor air quality of each configurable space.
Configurability depends on the boundaries of the system at hand, and the use cases of the actor. A Building Owner, who will likely have multiple tenants over their tenure, will desire HVAC systems that can be configured to different tenant needs. One investment, many use cases. A Tenant, who may have different spatial needs across the years of their tenancy, will desire HVAC systems that can be reconfigured to match their spatial layout. One investment, many use cases.
Configurability also refers to the ability to tune and optimize different functions based on the current need at hand. Forest fire season impacting outdoor air quality? Tune the building. Virus surge requiring higher ventilation rates? Tune the building. As Stewart Brand writes in How Buildings Learn: “All buildings are predictions… A good strategy ensures that, no matter what happens, you always have maneuvering room.”
How can we ensure that an investment in a building system is configurable for multiple scenarios?
Flexibility during times of virus surge
With the above measures in place, buildings will be all the more flexible to deal with time of virus surge. We need to be careful though to not overfit to today’s novel coronavirus. Rather, we should ensure that our building systems can be tuned to match the variety of characteristics each new contagion (or other assault) will offer, assuming certain severity thresholds are reached.
|Virus Surge||Control||Sense (Data)||Configurability|
|Ventilation||Increase fresh air rates, Reduce recirculation||View trending levels||Ability to vary rates & pressurization by room / space, depending on need|
|Indoor Air Quality||Uplevel filters||View trending levels||Prioritize “healthiest” first for re-entry|
|Thermal Health||Tune indoor relative humidity to reduce virus survivability & droplet nuclei persistence||View trending levels||Avoid heating/ cooling if no occupants present (only if disentangled from ventilation)|
You can read more about building recommendations during virus surge in this ASHRAE Position Document on Infectious Aerosols (last update April 2020).
Opportunities for A Building Technologist in Public Health
So where does that leave us? I like to conclude these explorations with a summary of next steps (in no particular order). These lists help me understand where I should prioritize MY next steps and focus for the next several months. They also help me create a “web” to catch any new clues that might just be at the periphery of my current focus. I also hope it helps others in this small (but growing?) niche to focus their own efforts.
- Establish governance for healthy buildings: Who is responsible?
- Define accountability among building stakeholders and empower the relevant entities
- Develop healthy building platforms between Building Owner <> Tenant <> Occupant
- For example, for HVAC– Ventilation, Thermal Health, Indoor Air Quality
- Offer Control, Data (Transparency), and Configurability through technology platforms
- Build and implement new (HVAC) technologies
- Further disentangle ventilation, sensible loads, latent loads, and distribution
- Decentralize air quality: decentralized control, decentralized supply, decentralized incentive structures
- (And do so in a way that reframes and reduces GHG emissions!)
- Build soft infrastructure for more coordinated distribution & maintenance
- Establish general awareness, Codes/standards
- Rethink financing mechanisms to reduce split incentives
- Build up skills training
- Contribute to ongoing science
- Sponsor Indoor Air Quality research through funding and data sets
While I discussed these opportunities through a perspective of commercial buildings (let’s of course hope that ongoing focus is applied to healthcare!), they are just as important to residential buildings as well– from single family to multi-family dwellings. These opportunities also apply to schools and government buildings. They apply to hotels. They apply to prisons. They apply to any building where people spend a majority of their time.
So what’s the thread between Public Health and Climate Change? It’s infrastructure, soft and hard. Each one of the opportunities above paves the way not just for infrastructural improvements for public health, but for climate change as well. Improving the platform between Building Owner, Tenant, Occupant? Win. Encourage new technologies? Win. Uplevel soft infrastructure across the building supply chain? Win. Contribute to further science in buildings? Win.
Buildings can be a powerful tool for personal, public, and climate health. Let’s get started already.
As before, title inspired by Bret Victor’s piece “What can a Technologist do about Climate Change?“
Art by Wu Guanzhong