By Robert BeanHVAC Systems Commercial Design Design-build Indoor Air Quality Residential Design
The influence of building materials, furnishings, finishings and a creative solution involving HVAC and interior design.
Over the decades I have sat in on countless industry meetings and participated in debates over education curriculums for industry members. Typically I sit on the side, most often alone in my beliefs that a large segment of the industry does not actually know what it needs to know. My experience is that when prodded for learning topics, many will ask for more of the same, just presented differently.
Henry Ford probably said it best when he stated: “If I had asked people what they wanted, they would have said faster horses.” I am with Henry – educational progress of any consequence is not achieved by “polishing the cannon ball.” In this case, the repetitive buffing of knowledge one already possesses.
If you really want to learn you have to follow the advice of business guru Peter Drucker and put yourself in a place where you do not shine and where your lack of knowledge and skills makes you scared, awkward and frustrated. As I say in my classes, learn to embrace the intellectual and emotional pain – it is a sign that you are learning something new. That is often far more useful than taking classes that only confirm what you already know.
So where am I going with this? Well, I have been saying for decades that hydronics and air-based HVAC designers cannot operate in isolation from the world of interior design. There is a non-trivial, consequential relationship between room geometry and finishes contributing to the ergonomics of the very space that the HVAC system is supposed to condition. This relationship directly affects the energy efficiency and indoor environmental quality.
I am going to first illustrate this with the National Research Council of Canada’s (NRCC) IA-QUESTi; a free, downloadable indoor air quality and emission simulation tool. I will demonstrate this again in a subsequent article in the March 2012 issue using the ASHRAE Nomograph for designing radiant panels. But, before I do this let me be very clear there is a significant difference between the educational and experience requirements of a professional interior designer and interior decorator; something I learned years ago from the folks at ASIDii.
According to our own Interior Designers of Canada associationiii, “Interior design is about more than just aesthetics. It is about finding creative design solutions for interior environments while supporting the health, safety and well being of occupants and enhancing their quality of life.” Does that not just sound like a nice fit with HVAC?
Tool assesses voc impact
The IA-QUEST tool was developed, “to help building designers, engineers and managers assess the impact of the volatile organic compound (VOC) emissions from building materials/furnishings on the indoor air quality in buildings.” Why is this important? As I have pointed out in previous articles, source control over contaminates is part and parcel of CSA F326 Residential Mechanical Ventilation Systems and ANSI/ASHRAE 62.1(.2) Ventilation For Acceptable Indoor Air Quality.
In fact, it is expected that the HVAC designer should be evaluating potential emission rates to ensure that the designed ventilation system is adequate in consideration of the interior finishes. The IA-QUEST tool, “calculate(s) the concentrations of contaminants that would occur in a ventilated indoor space due to emissions from materials contained within that space.”
Sounds like every designer should have a copy of IA-QUEST? But here is what I know to be true, given a choice between learning more about air filters, or floor coverings, the HVAC designer will likely choose to buff up his/her knowledge of filtration instead of learning about VOC emission rates from interior finishes. C’est la vie.
To illustrate the output of the program for floor coverings I have set up the simulation parameters based on Table 1, and then for comparison, selected carpeting with underlayment and unfinished hardwood from the program’s data base. After setting up the ventilation schedule for unoccupied and occupied periods around 600, 900, 1600, 1800 and 2400 hours (Figure 1), I ran the calculation to produce comparative emissions for each compound as illustrated in Figure 2 (hardwood) and Figure 3 (carpeting). The output units on the y axis are concentrations in mg/m3 with the x axis showing time in hours.
The uppermost red lines represents the TVOC, or total volatile organic compounds, with subsequent lines representing the various other components emitted during the simulation time. The data “teeth” or “peaks” represent the minimum and normal operational times of the ventilation schedule. Make note of the inventory list of chemicals below the x axis. Not surprisingly, the quantity is much less for the unfinished hardwood than that of the carpet. Likewise, the concentration of chemicals emitted in the former peaks at 0.42 mg/m3 in comparison to the latter of approximately 2.1 mg/m3. Due to the quantity of compounds emitted at lower concentrations in carpeting, I have adjusted the output in Figure 4 so you can see with somewhat better clarity the chemical soufflé that is emitted during the simulation period. Caveat: It is not accurate to assume that one simulation is representative of all coverings – most flooring manufacturers have been working diligently to reduce their VOC emissions and their respective data should be used in evaluations.
As with these types of programs, the output values mean nothing unless one can compare them to some value that has meaning to the users of the program, and also in this case, the occupants in the space. Health Canada and other organizations do publish some values that can be used to benchmark against the results, but as anyone competent in the world of IAQ knows, the ultimate test of chemical sensitivity will be the occupants themselves.iv
What does this mean? It means there is no shortage of assumptions going on in the world of ventilation design, since many designers never get to talk with the occupants and often do not have access to the schedule of interior finishes and so default to using the ventilation rate prescribed by CSA F326 without considering the influence from interior finishes and need for source control.
In winding up this first part of the demonstration, I want to reiterate that source control à la CSA F326 and ASHRAE 62.1(.2) means having an understanding of interior finishes — meaning interior design is not detached from the world of the HVAC designer. As you will see in the March 2012 article on flooring and radiant systems, neither the hydronics nor the air based designer is immune from this topic – remember this when upgrading your knowledge base. <>
Robert Bean, R.E.T., P.L.(Eng.), is a registered practitioner in building construction engineering technology (ASET) and a professional licensee in mechanical engineering (APEGGA). He has over 30 years experience in the construction industry specializing in energy and indoor environmental quality and is the author and lecturer for professional development programs addressing building science, thermal comfort quality, indoor air quality and radiant based HVAC systems. Visit www.healthyheating.com.
ii) American Society of Interior Designers
iv) Charles, K.E. Magee, R.J. Won, D.Y. Lusztyk, E., Indoor Air Quality Guidelines and Standards : Final Report 5.1, Table 6. Guideline Values for Organic Chemicals in Indoor Air (industrial and non-industrial settings) Research Report, NRC Institute for Research in Construction, 204 pp. 36. 2005-03-01