In a field of its own
Standard practice for evaluating residential indoor air quality concerns.
Building Mechanical Electrical HVAC Systems
Indoor Air Quality
Indoor air quality (IAQ) concerns in residential buildings range from irritation and discomfort, to health problems as a result of unacceptable exposures to odours, particulate, gases, chemical and biological matter. For these reasons in the continuum of construction there will always be expanding prospects for IAQ solutions for firms that are interested in increasing their services and product offerings.
Due to the intimate relationship between the health of the environment and health of the occupants, it is important that those interests are approached knowledgably through education, awareness and professionalism.
Let us start by stating IAQ is part of a comprehensive field of study referred to as indoor environmental quality (IEQ), which is coupled to an even bigger field of study in human factors and ergonomics.
For those pursuing IAQ opportunities, it will become apparent that the field is the intersection of many studies with each of those being many layers deep.
Specifically for buildings, IAQ stands as one of six primary terms within IEQ, expressed collectively as:
IEQ = IAQ +ITQ + ILQ + ISQ + IOQ + IVQ
where I = Indoor, Q = Quality
A = Air
T = Thermal
L = Lighting
S = Sound
O = Odour
V = Vibrations
As one can see, it is incorrect to imply that IAQ stands alone as a proxy for IEQ as is sometimes mistakenly communicated even by experts from within the health and building community. For example, the U.S. Centers for Disease Control and Prevention (CDC) has stated, “Indoor Environmental Quality simply refers to the quality of the air in an office or other building environments.” This statement has been copied and restated by countless “authorities” and continues to be used even though the CDC has since corrected its definition.
To bring the topic of separation to the discussion, an authoritative document, ANSI/ASHRAE Standard 62.2 Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings states, “This standard considers chemical, physical, and biological contaminants that can affect air quality. Thermal comfort requirements are not included in this standard (see ANSI/ASHRAE Standard 55-2010, Thermal Environmental Conditions for Human Occupancy).” Translation: residential IAQ practitioners must be clear that ventilation, indoor air quality and thermal comfort are stand-alone studies.
ASHRAE 62.2 defines IAQ as, “air toward which a substantial majority of occupants express no dissatisfaction with respect to odour and sensory irritation and in which there are not likely to be contaminants at concentrations that are known to pose a health risk.” The publication also states, “While acceptable IAQ is the goal of this standard, it will not necessarily be achieved even if all requirements are met.”
Some reasons for this include, diversity of sources and contaminants; range of susceptibility in the population; and perception and acceptance being affected by temperature, humidity, noise, lighting and stress.
Clearly IAQ is not just a matter for service providers defaulting to filtration and (de)humidification upgrades, in fact these solutions can often mask the source of the IAQ problem.
I have addressed much of the above in previous articles in HPAC, so why repeat the message? I hope to underline for HVAC professionals that one has to be clear in one’s objectives – understanding that an IAQ inspection would include addressing odour and irritation complaints due to contaminants. But how do you deal with the tricky, and often subjective, topic of smells? Also, what is an irritant and does that require the knowledge of a medical professional? How about contaminants? How do these differ from pollutants and toxicants? Does it matter?
One authoritative document that offers up a nice serving of guidance, including investigative flow charts, questionnaires and check lists, is ASTM D7297-14 Standard Practice for Evaluating Residential Indoor Air Quality Concerns.1 It says the, “Characterization of IAQ concerns and identification of their underlying causes require systematic observations and measurements of the indoor environment, its occupants and contaminant sources.”
The procedures in the ASTM D7297 include a three phase investigative procedure from telephone and face-to-face interviews, to follow up protocols for site investigations, assessments and measurements. The results of these exercises then serve as the basis for recommending corrective measures.
The Standard has several “pause points” throughout the process to allow investigators to take the time to “step back to assess all field observations and data that have been collected at any given point to determine or postulate potential causes.” This cannot be overemphasized as inexperienced or less professional service providers frequently want to solve problems using their skill set or with products in their inventory. In fact, during a pause point there may be cause to cease the investigation and call in another specialist.
In part this is the reason the Standard states, “Implementation of procedures given in this standard requires the investigator (or investigative team) to have adequate background in several areas: general principles of IAQ; interviewing techniques; building design and construction practices; basic understanding of heating and cooling systems and appliances; use of IAQ measurement equipment; interpretation of IAQ data; and technical report writing.”
One of the areas of concern I have for the Standard has to do with its suggestion that investigators, “could benefit from a review of existing medical records.” Whilst in the hand of the right person this may be a true statement, it is impossible to imagine how someone without a medical background and the obligatory ethics could or should be in possession of someone’s medical records. How this passed through the ASTM committee is as much of a mystery for me as Ross Perot or Donald Trump running for the presidency.
Despite this glaring inclusion, it does recover by bringing awareness to the hazards investigators can be exposed to during an investigation. The chemicals, varnishes, paints and fuels that people store in unmarked containers, along with clothes and bedding contaminated with mould, rodent and insect feces and bacterial contaminants found in bathrooms and kitchens and bedrooms, are all sufficient to call in public health officials. Those circumstances are not the place for someone who just wants to upgrade an air filtration system regardless of its benefits.
However, if the IAQ concern is based upon occupant-based odours and particulate or visible signs of soot or back drafting then it is likely the health authorities can stay home and the filter catalogue and combustion and pressure instruments can come out.
It is not possible to cover all the potential opportunities afforded to the IAQ industry in this space. Filtration solutions, humidity control, combustion analysis, air flow, velocity, duct leakage and system balancing, along with thermal comfort complaints of draft, inconsistent temperatures and cold floors are routine service call issues.
To move into the IAQ industry and beyond what is currently in your technicians’ skill sets, and beyond the capability of the products and tools found in your service vans, you need to start your own education program. Begin with a study of ASTM D7297. Though the document is an invaluable resource for identifying potential causes (what to look for) and can be used as the basis for recommendi
ng corrective measures, it is not a “how to correct” guide. Such corrective measures ultimately lay in the hands of the practitioner based on his or her experience and skills.
Robert Bean, who is president of Indoor Climate Consultants Inc., is a registered engineering technologist in building construction through the Association of Science and Engineering Technology Professionals of Alberta and a professional licensee in mechanical engineering through the Association of Professional Engineers, Geologists and Geophysicists of Alberta. He has served two terms as an ASHRAE distinguished lecturer, serves on ASHRAE committees TC 6.1 (Hydronics), TC 6.5 (Radiant), TC 7.4 (Exergy) and SSPC 55 (Thermal Comfort) and is a recipient of ASHRAE’s Lou Flagg Award.
1 ASTM D7297-14, Standard Practice for Evaluating Residential Indoor Air Quality Concerns, ASTM International, West Conshohocken, PA, 2014, www.astm.org
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May 11, 2022