Table of Contents
Executive Summary…………………………………………………………………………………………… pg. i
1.0 Introduction……………………………………………………………………………………………… pg. 1
2.0 Purpose of Study……………………………………………………………………………………….. pg. 2
3.0 Biowall Basics……………………………………………………………………………………………… pg. 2
3.1 Air Quality…………………………………………………………………………………….. pg. 2
3.2 Biofiltration……………………………………………………………………………………. pg. 5
3.3 Biowall………………………………………………………………………………………… pg. 6
4.0 Plants…………………………………………………………………………………………………….. pg. 7
4.1 Effect on Air Quality………………………………………………………………………….. pg. 7
4.2 Psychological Effects………………………………………………………………………… pg. 8
4.3 “Biophilia”……………………………………………………………………………………… pg. 9
4.4 A List of Plants for a Biowall…………………………………………………………………. pg. 10
5.0 HVAC Systems…………………………………………………………………………………………… pg. 10
5.1 Passive & Active Systems……………………………………………………………………. pg. 11
5.2 Energy Savings………………………………………………………………………………… pg. 12
6.0 Benefits of a Biowall……………………………………………………………………………………… pg. 13
6.1 Green Recognition………………………………………………………………………………… pg. 13
6.2 Benefits for the Occupants……………………………………………………………………. pg. 13
6.3 Benefits for the Building……………………………………………………………………….. pg. 14
7.0 Concerns…………………………………………………………………………………………………… pg. 14
7.1 Mould/Moisture Problems……………………………………………………………………… pg. 14
7.2 Insects……………………………………………………………………………………………. pg. 15
7.3 Allergies………………………………………………………………………………………….. pg. 15
7.4 Maintenance…………………………………………………………………………………….. pg. 16
8.0 Research Possibilities…………………………………………………………………………………….. pg. 16
9.0 Structure / Construction…………………………………………………………………………………… pg. 16
9.1 Cost of the Biowall…………………………………………………………………………………………. pg. 17
10.0 Funding……………………………………………………………………………………………………... pg. 18
11.0 Recommendations & Conclusion………………………………………………………………………… pg. 19
12.0 References…………………………………………………………………………………………………. pg. 20
13.0 Appendices…………………………………………………………………………………………………. pg. 23
Appendix 1 Local Biowalls ……………………………………………………………………………… pg. 23
Appendix 2 Possible funding Agencies……………………………………………………………….. pg. 24
Executive Summary
A Biowall is a vertical garden. It acts as a natural air filtration system. As air moves through the wall, impurities are removed and clean air is distributed throughout the building via the HVAC system.
The study of a Biowall at George Brown College was undertaken for the following reason. In an effort to provide a greener campus for the students and faculty, George Brown College is in the process of considering different options for incorporating sustainable technology within the college. A Biowall is being proposed to be situated in the atrium of the Casa Loma Campus E building. A Biowall would not only function as an aesthetic focal point to the building, but would help clean the air, create a forum for applied research and a visual impetus to continue pursuing sustainable development within the college.
The results of the study produced the following conclusions. The biowall could be effectively put to use in the proposed location. Its benefits could be:
· Cleaner air with fewer pollutants such as formaldehyde, VOC’s etc.
· Eventual cost savings through energy savings as ASHRAE implements a provision for Biowalls
· Improved well being for building occupants shown in studies indicating the greening of indoor spaces with reduction in fatigue levels and reduction in absenteeism
· Applied Research projects for example in possibly cleaning rainwater used for the Biowall.
The cost for the Biowall itself is estimated at $240,000.00 with an outside cost of $400,000.00 to include related costs such as structural engineering, HVAC, architectural and a contingency fund.
At George Brown College, the Atrium space being considered has a unique situation. It is an unadorned, unfinished 3-storey concrete hole. This space looks like a mistake in the design of this building. Yet, it is a focal point as the college community and its guests enter the premises. Introducing a Biowall here would change this mistake into a beautiful, healthful and purposeful living wall.
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1.0 Introduction
In our day to day lives we all face a variety of risks to our health and well being. As cities become more congested, we are constantly exposed at varying degrees of risk to environmental pollutants produced by fuel emissions, chemicals, building materials, metals, plastic compounds, bacteria etc… . Some risks are simply unavoidable; others we choose to accept because to do otherwise would restrict our ability to function within our society. Currently there is a shift towards investigating and implementing projects towards reducing the amount of pollutants and garbage we produce as individuals, institutions and as a society. Indoor air quality (IAQ) has recently become an issue due to scientific evidence that pollution levels within homes and buildings pose a more serious threat to our health than the outdoor air in industrialized cities (Hodgson, 1997). People spend on average up to 80% of their time indoors on a daily basis (Fjeld, 1998) thus, for many; the risks to health may be greater due to indoor air pollution than to outdoor air pollution. In addition, people who spend more time exposed to indoor air pollutants for longer periods of time are often more susceptible to the effects of indoor air pollution. Population segments that are most at risk include the young, the elderly, and the chronically ill and especially those suffering from respiratory or cardiovascular disease (US EPA, 2006). The fact is, that we are all at risk and after years of exposure to indoor pollutants the effects gradually compound as we age.
The Environmental Protection Association (EPA) suggests three basic methods of improving indoor air quality: control the source, improve ventilation, or use an air purifier. Another method of dealing with this type of problem is a Biowall, a relatively new technology. A Biowall is an indoor vertical hydroponic green wall. Air is actively drawn through the wall of plants and the root system in order to purify the air within a building (Darlington, 2007). Biowalls are gaining acceptance in Asia, Europe and North America as a component in ecologically sustainable development. With the growing concern of climate change and the need to develop sustainable strategies for urban environments, building sustainably means more than just green building materials, construction techniques, and site selection. It also means choosing systems that will create healthier environments using materials and methods that consume less energy than present technology. The sustainable idea with regards to a Biowall is to improve the environment within a building while increasing energy savings. Providing students and faculty with the incentive of a healthy indoor environment by using alternative energy sources and air purification methods such as a Biowall in order to create and maintain a healthy indoor environment will help to improve the quality of life for the community that attends our college every day.
In today’s world there is considerable emphasis on sustainable design. With all the concerns with the environment, Indoor Air Quality (IAQ) is an important issue from a biological, social and economical point of view.
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There are several design strategies that can be used to deliver good IAQ. Controlled ventilation, proper design, and the use of appropriate healthy building systems can provide good indoor air quality if used as part of a holistic design approach.
This paper will investigate the feasibility, benefits and sustainability of installing a Biowall within the atrium space in E building Casa Loma campus.
2.0 Purpose of Study:
George Brown College’s Applied Research and Innovation Department has hired students from the Architectural Technology program to conduct a general overview of the Biowall technology and its appropriateness for our college. George Brown College is in the process of considering different options for incorporating green technology within the college. One of those options being considered is the installation of a Biowall in the E Building atrium of the Casa Loma campus.
Although some universities have already done studies of these walls and have constructed these walls, George Brown College feels that it is necessary to conduct its own study to better understand how this technology works, and whether it delivers on its promise of cleaner air, energy savings, and other benefits for our specific site. The team was given the task of collecting information on Biowalls to understand its technology, effectiveness as well as addressing any critical issues that may be of concern.
3.0 Biowall Basics:
3.1 Air Quality
George Brown students spend their time inside. With so many hours being spent indoors, it is essential for our buildings to provide high quality air to those who occupy them, since this impacts their well-being. Indoor air quality is a major health concern and one of the major energy expenses for maintaining an adequate indoor air climate. Buildings are constructed as air tight as possible in order to help lower energy costs. While this does trap the “conditioned” indoor air within the structure, it also traps gaseous contaminates that arise within the space. One particular concern is the presence of Volatile Organic Compounds (VOCs) which are represented by chemicals such as formaldehyde, benzene and toluene. These chemicals arise from activities that occur within the building envelope, building materials, and the occupants themselves. VOCs may arise from such products that include:
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Ø Off-gassing of building materials such as drywall, adhesives, textiles, fabrics, plywood etc.
Ø New office furniture, rugs
Ø Cleaning agents, solvents, glues, caulking agents, paint
Ø Electronics (computers, photocopiers, fax machines, computer screens)
Ø Human occupants (hair spray, body gels, anti-perspirants, and other perfuming agents).
Source: (Berube, 2004).
If these chemicals are not controlled in a respectful manner it may accumulate to the point of affecting the well-being of the occupants.
More than 10 years have passed since the US Environmental Protection Agency (EPA) ranked indoor air pollution as one of the top five environmental threats to public health and one of the largest remaining health risks in the United States. According to the Centers for Disease Control and Prevention (CDC), the most common actual cause of death in the US in 2000 were tobacco (435,000), microbial agents (such as influenza and pneumonia, 75,000), and toxic agents (such as pollutants and asbestos, 55,000) (CDC Fact Sheet). Also, the American College of Allergy, Asthma and Immunology in 2000 noted that 50 percent of all illnesses are either caused or aggravated by poor indoor air quality (Abu-Shalback, L. The Impact of IAQ).
Some VOCs detected in indoor air are recognized carcinogens and there are reports of exposure to VOCs resulting in symptoms varying from headache, nausea, dizziness to eye, skin, and throat irritations. The odour associated with some VOCs may also cause complaints.
The impacts of indoor air pollution also affect the quality of a person’s life in term of reduced or limited activities, limited employment opportunities, and reduced productivity. Sick building syndrome (SBS) is a collection of non-specific symptoms such as eye, nose, skin and throat irritations; headaches; fatigue; and/or skin rashes that have no known cause. A number of indoor building conditions such as inadequate building ventilation, elevated levels of VOCs, and other environmental stressors have all been implicated as potential causes.
“A paradigm shift from rather mediocre to excellent indoor environments is foreseen in the 21st century. Based on the existing information and on new research results, five principles are suggested as elements behind a new philosophy of excellence: (FASTS, Indoor Air Quality in the 21st Century.)
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1. Better indoor air quality increases productivity and decreases SBS symptoms
2. Unnecessary indoor pollution sources should be avoided
3. The air should be served cool and dry to the occupants
4. “Personalized air”, i.e. a small amount of clean air, should be served gently, close to the breathing zone of each individual
5. Individual control of the thermal environment should be provided”
These principles of excellence are compatible with energy efficiency and sustainability. (FASTS, Indoor Air Quality in the 21st Century.)
Table 1: Canadian Guidelines for Common Indoor Contaminants
Contaminant / Maximum Exposure Limits (ppm)*¹Carbon dioxide / 3500 [ L ]
Carbon monoxide / 11 [ 8 hr ]
25 [ 25hr ]
Formaldehyde / 0.1 [ L ]
0.05 [ L ] **
Lead / Minimum exposure
Nitrogen dioxides / 0.05
0.25 [ 1 hr ]
Ozone / 0.12 hr
Sulfur dioxide / 0.38 [ 5 min ]
0.019
Benzene / 10
Toluene / 200
Trichloroethylene / 100
Naphthalene / 9.5
* Numbers in brackets [ ] refers to either a ceiling or to averaging times of less than or greater than eight hours (min = minutes; hr = hours; L = long term. Where no time is specified, the average is eight hours.)
** Target level is 0.05 ppm because of its potential carcinogenic effect. Total aldehydes limited to 1 ppm.
Source: (Hum, R., 2007) 4
Biowalls can address concerns with formaldehyde, sulfur dioxide, benzene, toluene trichloroethylene and naphthalene. These chemicals arise from activities that occur within the space, building materials and the occupants themselves. If not controlled, the contaminants may accumulate to the point of influencing the well-being of occupants (Darlington, 2004). For further analysis on the affects of Biowalls and biofiltration systems on indoor air quality refer to the draft report “Indoor Air Biofilters as a means of Improving Indoor Air Quality: A Review of Existing Literature” by Alan Darlington.
One way to limit and control the accumulation of VOCs within the building envelope is through the use of a Biofiltration system.
3.2 Biofiltration
Biofiltration is defined as the process of drawing air in through organic material (such as moss, soil, and plants) resulting in the removal of organic gases, such as volatile organic compounds and other contaminants. Microorganisms inherent within the biofilter absorb, minimize, separate, breakdown and transform dangerous compounds so as to re-circulate clean air. Up to 80% of dangerous compounds in indoor environments can be eliminated through the use of a biofilter. (Deshusses, 1996)
Figure 1. Relative Performance of Various Biofilter Support Media
Fig.1 Relative Performance of Various Biofilter Support Media (Deshusses, 1996)
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Although widely employed, the scientific community is still unsure of the physical phenomena underpinning biofiltration, and information about the microorganisms involved continues to be developed. A biofilter system is a fairly simple device to construct and operate and offers a cost-effective solution provided the pollutant is biodegradable within a moderate time frame, at reasonable concentration, and that the airstream is at an organism-viable temperature. For large volumes of air, a biofilter may be the only cost-effective solution.
This type of system is generally used in large masses in industrial air pollution control. However, Dr. Alan Darlington, (a professor at the University of Guelph who completed his PhD in horticulture at the University of Guelph in the Controlled Environmental Systems Research Facility) has researched and focused on the use of botanical biofilters as means of maintaining air quality in the indoor environment. He is the President and CEO of Air Quality Solutions, a company that builds and has a patent to the technology used to build these types of biofilters indoors. We are calling these walls Biowalls.