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Cassbeth was started in 1997. We are a systems engineering technology company. We pursue projects that we think have a critical need but few are properly addressing. We capture our work in books, software, graduate level systems engineering courses, and intellectual property.

About Us

With the outbreak of COVID-19 Cassbeth began research on the disaster from a systems perspective and quickly focused on ventilation. The research is found here. Return to Life. The IP is found here: Airborne Contagion Assessment Ventilation Alarms System.

The Cassbeth analysis showed that the problem is massive within small enclosed spaces, problematic in large spaces, and extremely rare in outdoor spaces. It was also found that the technology exists, is relatively low cost, and is part of the system solution in elite settings. The problem is a social problem where the technology and system solutions must find their way into all facilities especially schools, airports, airplanes, bars, restaurants, etc. where large numbers of people congregate and where the facilities are not properly maintained or operated.

Inspiration

Ask not what your country can do for you, ask what you can do for your country -- President Kennedy. Ask not what others can do for you, ask what you can do for others is the corollary and inspired an entire generation that provided the best aspects of world that this generation enjoys. I would like to say that this generation is following in this great tradition but that is not the case. Extreme self interest and stupid people have taken control in all aspects of todays world. This generation is being challenged and so far in the 21st century they are failing miserably. Ventilation problems that led to a world wide pandemic is only a symptom of the deeper problem.

This critical systems work on facility ventilation was validated and inspired to continue by:

A Paradigm Shift to Combat Indoor Respiratory Infection

In May of 2021, 39 scientists published "A Paradigm Shift to Combat Indoor Respiratory Infection" calling for a paradigm shift in how citizens and government officials think about the quality of the air we breathe indoors. At some point in history this document will be referenced for decades.

ABSTRACT

There is great disparity in the way we think about and address different sources of environmental infection. Governments have for decades promulgated a large amount of legislation and invested heavily in food safety, sanitation, and drinking water for public health purposes. By contrast, airborne pathogens and respiratory infections, whether seasonal influenza or COVID-19, are addressed fairly weakly, if at all, in terms of regulations, standards, and building design and operation, pertaining to the air we breathe. We suggest that the rapid growth in our understanding of the mechanisms behind respiratory infection transmission should drive a paradigm shift in how we view and address the transmission of respiratory infections to protect against unnecessary suffering and economic losses. It starts with a recognition that preventing respiratory infection, like reducing waterborne or foodborne disease, is a tractable problem.

The following are key extracts from the paper, A Paradigm Shift to Combat Indoor Respiratory Infection.

There is great disparity in the way we think about and address different sources of environmental infection. Governments have for decades promulgated a large amount of legislation and invested heavily in food safety, sanitation, and drinking water for public health purposes. By contrast, airborne pathogens and respiratory infections, whether seasonal influenza or COVID-19, are addressed fairly weakly, if at all, in terms of regulations, standards, and building design and operation, pertaining to the air we breathe.

Most modern building construction has occurred subsequent to a decline in the belief that airborne pathogens are important. Therefore, the design and construction of modern buildings make few if any modifications for this airborne risk (other than for specialized medical, research, or manufacturing facilities, for example). Respiratory outbreaks have been repeatedly “explained away” by invoking droplet transmission or inadequate hand hygiene.

For decades, the focus of architects and building engineers was on thermal comfort, odor control, perceived air quality, initial investment cost, energy use, and other performance issues, whereas infection control was neglected. This could in part be based on the lack of perceived risk or on the assumption that there are more important ways to control infectious disease, despite ample evidence that healthy indoor environments with a substantially reduced pathogen count are essential for public health.

It is now known that respiratory infections are caused by pathogens emitted through the nose or mouth of an infected person and transported to a susceptible host.

Although the highest exposure for an individual is when they are in close proximity, community outbreaks for COVID-19 infection in particular most frequently occur at larger distances through inhalation of airborne virus laden particles in indoor spaces shared with infected individuals

There are ventilation guidelines, standards, and regulations to which architects and building engineers must adhere.

None of the documents provide recommendations or standards for mitigating bacteria or viruses in indoor air, originating from human respiratory activities. Therefore, it is necessary to reconsider the objective of ventilation to also address air pollutants linked to health effects and airborne pathogens.

There needs to be a shift in the perception that we cannot afford the cost of control, because economic costs of infections can be massive and may exceed initial infrastructure costs to contain them. The global monthly harm from COVID-19 has been conservatively assessed at $1 trillion ([internal ref]), but there are massive costs of common respiratory infections as well. In the United States alone, the yearly cost (direct and indirect) of influenza has been calculated at $11.2 billion; for respiratory infections other than influenza, the yearly cost stood at $40 billion.

We encourage several critical steps. First and foremost, the continuous global hazard of airborne respiratory infection must be recognized so the risk can be controlled. This has not yet been universally accepted, despite strong evidence to support it and no convincing evidence to refute it.

Comprehensive ventilation standards must be developed by professional engineering bodies. Organizations such as the American Society of Heating, Refrigerating and Air-Conditioning Engineers and the Federation of European Heating, Ventilation and Air Conditioning Associations have ventilation standards, and during the COVID-19 pandemic, they have proposed building and system-related control actions and design improvements to mitigate risk of infection. However, standards must be improved to explicitly consider infection control in their statements of purpose and definitions. New approaches must be developed to encourage implementation of standards (e.g., “ventilation certificates” similar to those that exist for food hygiene certification for restaurants).

The COVID-19 pandemic has revealed how unprepared the world was to respond to it, despite the knowledge gained from past pandemics. A paradigm shift is needed on the scale that occurred when Chadwick’s Sanitary Report in 1842 led the British government to encourage cities to organize clean water supplies and centralized sewage systems. In the 21st century, we need to establish the foundations to ensure that the air in our buildings is clean with a substantially reduced pathogen count, contributing to the building occupants’ health, just as we expect for the water coming out of our taps.

.The City of Philadelphia

Healthy Infrastructure - Philadelphia Water Works

The Philadelphia Water Works was the first water treatment facility in the United States built between 1812 and 1872, it operated until 1909. It was a model for all future water works to follow in the New World. People would flock from around the planet to see this facility which combined engineering and art to solve a massive problem of safe water for the inhabitants of Philadelphia. It was born of necessity as the people decided they would not tolerate yet another yellow fever outbreak. The Museum sits on top of the original water reservoir that provided the city with water. As Philadelphia grew the reservoir and Water Works could no longer meet the needs of the city and new projects eventually replaced this once great technological and artistic achievement. It stopped operations in 1909.

The Philadelphia Art Museum and Water Works

A post vaccine world implies that everyone has received a vaccine against the COVID-19 virus. However, we know that will not happen. In the USA some will refuse the vaccine. In many countries the poor will not have access to the vaccine. The idea of a post vaccine world also suggests that we can return to the pre-COVID world. However, we know that is not the case. The contagion and its variants will be in the environment for decades. This is not unlike the situation that existed in the early part of the last century where there were deadly contagions that were part of normal life. It was not until multiple technologies were introduced in multiple systems that there was a decline in many deadly contagions in the USA and other parts of the world. These technologies and systems were embedded in:

Philadelphia Restaurant Program

In the wake of the COVID-19 disaster the city of Philadelphia has once again taken lead actions like the Enhanced Ventilation Standards for Indoor Dining and Application Form for Increased Dining Capacity dated February 14, 2021. The Enhanced Ventilation Standard calls for 15 air changes per hour (ACH) for establishments wanting to double their seating capacity. The approach is brilliant and uses the incentive to increase income to offset any possible costs that may be needed to increase ventilation. The ventilation level increase is large and will significantly mitigate contagion levels in the restaurant. It is obvious that it is traceable to existing engineering requirements associated with contagions rather than subjective minimum comfort levels. As part of the initiative they posted how to videos:

https://www.youtube.com/watch?v=HlneLDi9r54 (video on how to calculate air changes per hour)
https://www.youtube.com/watch?v=58uRfAxh6Cw (video on how to complete the application)

These people are brilliant. The city of Philadelphia is leading the world on how to deal with the COVID-19 disaster for indoor settings. Unfortunately this program stopped in May 2021 leaving a void in this very important area of ensuring public buildings have ventilation levels that mitigate contagions rather than just provide minimum comfort levels. However, the model exists along with the recommended ACH level.

Philadelphia School Ventilation Disclosure

The city of Philadelphia has also taken the time and effort to understand their school facilities and they have performed an extensive site survey (air balance reports) of all their school. The school district has 240+ schools and 12,000+ rooms. They made this critical information public via their website. Once again Philadelphia has taken a lead in trying to deal with another aspect of the COVID-19 disaster and that is to understand the current state of the schools and share the data with the Philadelphia taxpayers and people everywhere.

Fresh Air Movement From The Last Century

Before the introduction of antibiotics in the 1940s many infectious diseases such as Tuberculosis were treated using a fresh air cure. Tuberculosis spreads from person to person via coughing, sneezing and spitting. Tuberculosis usually affects the lungs. Left untreated, up to two thirds of those infected with Tuberculosis will die. Starting in the 19th century, Tuberculosis patients were forcibly isolated in sanatoriums built in remote locations all around the world, including Australia, where they were provided with the top treatment of the day: fresh air and sunlight.

Dr. Auguste Rollier had a substantial cure rate for tuberculosis by exposure to sunlight, or heliotherapy. His students are pictured here working outside in 1925.

Fresh air treatment was accepted and practiced in all types of settings including special treatment sanatoriums and hospitals.

Fresh Air treatment for TB sufferers in London 1936

1937 New Ventilation Technology Study

A key study was performed in Philadelphia by W.F. Wells on the use of a new technology - Ceiling Level UV lights. He was an Associate Professor in Research in Airborne Infection at the Laboratories for the Study of Airborne Infection in the Department of Preventive Medicine and Public Health at University of Pennsylvania School of Medicine, Philadelphia, PA. The findings were presented in part before the Engineering Section of the American Public Health Association at the Seventy-first Annual Meeting at St. Louis, Mo., October 30,1942. It was supported by a grant from the Common wealth Fund to the University of Pennsylvania for the study of the mechanics of airborne infection and control. The design was based on science and engineering using numbers to understand the system and its level of performance.

Swarthmore Public School Classroom circa 1937 - 1943

The rest is history. The history is of a people who knew about the need to address airborne infections. They provided us with modern forced air Heating Ventilation and Cooling (HVAC) systems and Ceiling Level UV-C systems to clean the air in buildings so that they approach what is found outside in the fresh air. They built upon the fresh air movement. Today this generation must rise to the occasion and deal with fresh air in all our buildings using the tools of their time - social media, Internet, smartphones, computers, etc.

Is your faculty ventilation turned on? If not why?

Do you know its performance level in terms of Air Changes per Hour (ACH)? If not why not?

Do you care? If not why not?


VENTILATION: WHY does no one take it seriously?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8251269

Indoor Air. 2021 May; 31(3): 605–607.
Published online 2021 Apr 20. doi: 10.1111/ina.12824
PMCID: PMC8251269
PMID: 33876855

VENTILATION: WHY does no one take it seriously?

Jan Sundell,corresponding author 1 John Spengler, 2 and Pawel Wargocki 3
1 School of Environmental Science and Engineering, Tianjin University, Tianjin China
2 T.H. Chan School of Public Health, Harvard University, Cambridge MA, USA
3 Department of Civil Engineering, Technical University of Denmark, Lyngby Denmark

A further reflection on ventilation.

After high school, I started my university studies at the Royal Institute of Technology (KTH) in Stockholm, Sweden. I really had no reason to choose it, but my grades made it possible… with better grades, I might have gone to Karolinska Institutet for medical studies. At that time, it was, however, a great achievement to go to such a good university. It all was because the Social Democratic Party in Sweden had made it possible, also for kids from low-income families to study in universities. There was a good loan for housing and studying and a good system for those with children. I soon had two children when studying for my master's degree.

My study was first on energy engineering, and then, I chose heating, ventilation, and air conditioning (HVAC) engineering as my special focus topic. For my master's degree work, I decided to study ventilation in homes together with one of my high school mates, Bengt Carlsson. Possibly the greatest mistake in my life.

At that time in Sweden, the Professors arranged for your future work. I could choose between the newly set up Environmental Protection Agency (EPA) and then the new Board of Urban Planning and Building (Statens Planverk in Swedish). I chose the latter and became responsible for developing building codes on installations, including ventilation. In retrospect, I can imagine my life at EPA, with much greater resources…perhaps, I, in that case, would have seen PM2.5 as an important topic today?

Anyway, in 1969, I and Bengt Carlsson wrote our master thesis on “Bostadsventilation—en orienterende undersokning” (Home ventilation—an orientating study). It was actually a good study and historically very important. We measured airflows in supply and exhaust terminals, and we measured the pressure difference between rooms and between indoors and outdoors. So, we knew the main airflow direction. We found a mean air change per hour (ach) of 0.8 with much lower values for naturally ventilated homes at 0.27 ach. These values are certainly lower than actual values as we did not measure with a tracer gas method. It was commented in the report that sometimes you did not need measuring instruments to indicate the airflow direction. It was enough to use odors (the same as at offices in Tsinghua University and Tianjin University today), and the smell of feces odor from restrooms is all you need.

I started my work at Statens Planverk, being responsible for installations in buildings, including heating, ventilation, and water. After the oil embargo in the Middle East in 1973, the focus was on energy and ventilation. With good insulation in buildings, ventilation was very important for the total energy need in buildings.

The first idea was to use maximum allowable concentration (MAC) values for workplaces for indoor air pollutants. I soon realized that it did not work, as people in homes, schools, etc., are not working adults, they are young, old, and not always healthy. So MAC values could not be used. I could use C.P. Yaglou's study on human odor from 1936, but is odor health? Happily, we had a new study from The Radiation Protection Agency and the Building Research Institute in Sweden, a study on radon in homes. In Sweden, radon is coming from the ground but also from building materials like "blue concrete." The latter is a rest product from uranium mining. With the building as the main source, ventilation is important. The data showed that if the ventilation rate is less than 0.5 ach, the radon concentration will increase. This is the main reason for 0.5 ach in building codes or standards. Soon after, an infestation of house dust mites (HDM) was shown to be closely associated with ventilation rate in homes. The HDM data (as affected by outdoor–indoor relative humidity (RH) continuum) showed that while 0.5 ach was ok in Stockholm, we might need 0.7 in Copenhagen.

Anyway, 0.5 ach (I would call it the "Sundell number") is widely used today in many national regulations and standards, but very few know its origin.

From that time, I understood that my interest in ventilation was just mine. Who else cared about ventilation? I soon learned that the big companies in this field did not have good ventilation in their offices, and the big professors did not have it in their offices at all. And today, the ventilation in new offices is still poor, and many have no ventilation. In China, we have some 200-300 universities lecturing about HVAC, but no one lecturer has a well-ventilated office.

The main thinking must be that ventilation may be needed in some industries or hospital settings. And even when it is needed, ventilation can be easily managed by opening windows.

I personally think that ventilation always meant industrial ventilation in China with the knowledge coming from Russia (e.g., V.V. Baturin, who wrote a textbook on Fundamentals of Industrial Ventilation) and that the focus in China has been on air conditioning with the knowledge from the United States (e.g., ASHRAE Fundamentals). To me, air conditioning is simple, like heating. You know exactly what to design for, that is, thermal comfort and thermal loads. Is ventilation being taught adequately? We know that ventilation is much harder to design for than is heating and air conditioning. For example, how much outdoor air is needed? Should we use ach or L/s per person? And finally, what about energy?

So far, in China and most of the world, energy has been the top priority. And ventilation has always been seen as having a negative impact (as it means more energy being consumed).

The main problem is that ventilation has been mainly seen as an engineering problem, but in reality, it is a public health topic.

What was discussed in Sweden in 1974? We had to reduce energy use in buildings, and the easiest way is to reduce ventilation. How to do it?

Natural ventilation needs no energy for fans, so perhaps that is the best solution? Sadly, natural ventilation has difficulties for controlling building tightness, with openings for inlet and outlet, controlled by wind speed and direction, and the temperature difference between indoor and outdoor. In reality, this means that the natural ventilation rate may be too high in a cold climate. A special problem with tight buildings is that you can get back draught in either kitchen or bathroom, meaning that the air was coming in either of these rooms and going out in the other. When this happens, it is very hard to change the flow direction until the climate gets warmer. This led Sweden to set the mandatory ventilation to stop the back draught in natural ventilation systems.

A further problem with natural ventilation is that it needs more ducts and hence building construction costs, as you need exhaust ducts (shafts) going through the roof.

In total, the discussion in Sweden found that natural ventilation does not work well, using more energy and being more expensive than mechanical systems.

The solution was mechanical ventilation with heat recovery—a simple solution to get reasonable ventilation and save energy. This has been the standard in Sweden since 1975.

Mechanical ventilation is a very simple system with ducts, fans, and perhaps filters (in homes).

The main problem with such systems is that they need good design and maintenance.

When I started at the Swedish Occupational Safety and Health Agency (OSHA), I was responsible for ventilation. I soon started a study with the best person in industrial ventilation in Sweden, Göran Allhammar, to see whether mechanical ventilation works. We studied some 30 buildings, measuring ventilation, and comparing it with design values and values from commissioning.

The result was shocking to us as what we measured was far away from what was designed for or commissioned. To have an outdoor airflow in a room was like winning on a lottery. A total catastrophe! (I have the results in Swedish—reports, and articles).

So mechanical ventilation did not work, as no one cared about it. Just installing ducts and fans, …… and filters, that are not properly checked.

I thought we needed a mandatory control of ventilation installation, which we eventually got ten years later. But obviously, the control did not work well. Can you trust an HVAC engineer?

In summary, ventilation is something that some companies make money on (by selling ducts, filters, fans…), but no one seems to realize, as I have, that it is important to make it work.

So, I am sorry I have ever got into this business… NO ONE CARES.

And of course, today in the United States or China students are not taught properly about ventilation. They are taught to design air conditioning!!!

A serious discussion about ventilation, that is, the need, how, how much, has not started yet.

And then, we have the "new" ideas about intelligent ventilation…. "MY GOD, THEY KNOW NOTHING!!"

In China today with new campuses in Tianjin for Tianjin University, a top university in HVAC, and Nankai…. and 14 other universities…. and in Tsinghua and all universities with HVAC education…. NO functioning VENTILATION…like in the United States. The same…

And the negative energy consequences are huge! Natural ventilation is NOT saving energy. Heat recovery in a well-functioning mechanical system does.

I am sorry I ever got into "ventilation"… no one takes it seriously!

Jan Sundell,
Former Editor-in-Chief of Indoor Air

I received this editorial contribution by email from our former Editor-in-Chief, Jan Sundell, on February 17, 2019. Jan probably wrote it from his hospital bed. To my regret, I did not submit his editorial on his behalf earlier. Indoor Air published an editorial "In Memory of Professor Jan Sundell (July 10, 1943-May 27, 2019)" (Indoor Air. 2019; 29:701-703). What would he do if he were with us in the ongoing COVID-19 pandemic? He warned us of the risk of poor ventilation in his life, in his publications, in his presentations, and during his many conversations with many of us. Why weren't we ready? While the world is combating the pandemic, I sincerely recommend this editorial to our readers for us to remember Jan’s life, work, and friendship on his second death anniversary.

Yuguo Li,
Editor-in-Chief of Indoor Air

Jan’s words ring so true in our Time of COVID-19. Over the summer of 2020, we assisted local school districts struggling to reopen. We found building management systems were dysfunctional, unit ventilators in a classroom being used as an extra shelf space with vents covered, and a basic lack of understanding about the importance of ventilation. Sadly, the only reliable way to provide a safe environment was to install supplemental air cleaners to provide higher clean air delivery.

In our current Aviation Public Health Initiative with airlines, airports, and aircraft manufacturers, we again had to demonstrate the importance of ventilation as a critical mitigation strategy, particular when mask wearing, and physical distancing were not enough. It took the evidence from measurements we made on airplanes and terminal buses to convince the air carriers and airport operators of the importance of ventilation. We made the case that high ventilation rates needed to be maintained throughout the gate-to-gate time on a plane.

Jan had a huge influence on our field on Indoor Science. He always seemed to be ahead of many of us. His influence is still present. My doctoral student Jose Cedeno demonstrated higher use of University Health Services for respiratory illnesses was associated with high occupancy of dorms. The earlier work of Jan and his colleagues at Tianjin University inspired us.

Jan’s living legacy and testimony to his vision and persistence are the China Children Health and Housing studies conducted in numerous Chinese cities. He has inspired a generation of students and young investigators to appreciate the health implications of indoor environments.

Jan’s friend, Jack Spengler,
Harvard T.H. Chan School of Public Health,
Cambridge

Jan was an extraordinary person. It is seen in the above text, probably one of his very last. He was a philosopher, yet a very pragmatic one. He did not follow the mainstream and had his opinions; they made you think. This is how I remember him when we first met in 1996, and he talked about the lost TVOC. Jan was passionate about public health. His passion was ventilation and big data, besides good jazz and few other things. He taught me (us) how to read and use scientific literature. His series of multidisciplinary reviews, unique at that time, laid the ground for new scientific developments. Jan wanted to collect big data. He believed that by monitoring in many places we would learn more. He launched studies in Europe, America, and Asia. Today, big data is a buzzword; back then, it was much more difficult to implement when he started. But he tried and made it happen. Jan had a special contact with students and young scientists; he promoted and introduced them to the big scientific world. I am privileged to be one of them. Jan believed that multidisciplinary research and especially focus on health were a way forward for indoor air field. We see today he was absolutely right. If only we had followed his advice on ventilation back then, we would be much better off today. We miss him….

Pawel Wargocki,
Technical University of Denmark, Lyngby,
President, ISIAQ Academy of Fellows


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