IAQ 2016 Defining Indoor Air Quality: Policy, Standards and Best Practices Co-Organized by ASHRAE and AIVC

Ventilation in multi-family buildings throughout North America is typically provided using a pressurized corridor system whereby make-up air pressurizes the corridor and passes in to the suites. The system relies on the directed airflow from the corridors to the suites to provide proper ventilation to maintain indoor air quality requirements. Previous studies have indicated that a majority of the designed ventilation air is not being delivered to the suites. This leads to potential for indoor air quality issues and occupant complaints of discomfort. Temperature, relative humidity, and carbon dioxide (CO₂) sensors were installed in suites of a 13 story multi-family building in Vancouver, BC to monitor indoor air quality between August 2012 and August 2015. Measurements were recorded at 1-hour intervals to allow for a comparison of indoor conditions during different seasons and between suites within the building. Significant differences were found when comparing the indoor air quality between suites located on the upper floors (9-12) and the lower floors (2-4). The CO₂ concentrations in the upper suites exceeded 1000ppm less than 5% of the time compared to 55-85% for lower suites. The difference in CO₂ concentration can be attributed to higher ventilation rates provided by the mechanical system as measured using both perfluorocarbon tracer testing and continuous differential pressure measurements. CO₂ concentrations showed a cyclic profile with the highest concentrations seen during December and low concentrations in July. The range of average monthly CO₂ concentration was greater for suites on the lower floors (800ppm to 1800ppm) compared to the upper floors (550ppm to 800ppm). The lower summer CO₂ concentrations in all suites are attributed to occupant window opening behavior providing improved ventilation. Temperature and relative humidity measurements throughout the study were typically within the design parameters (21 to 25° C and 30% to 60%, respectively) for all suites. A trend for higher indoor dewpoint temperature was found in suites on lower floors leading to greater potential for condensation and mold growth. The elevated CO₂ concentrations found in this study are greater than those proposed from ASHRAE ventilation guidelines and may have detrimental effects on building occupants. The results at this case study building are likely representative of conditions of many low to high-rise multi-family buildings ventilated with pressurized corridor systems. Alternative ventilation methods are recommended to improve indoor air quality and reduce occupant exposure.

Attached garages are a staple of modern convenience. They allow access to and from the living space without exposure to the elements, and they keep vehicles and other contents warmer in cold weather then their detached counterparts. As such they are a sought after feature in both the real estate and new construction markets. For all their conveniences, attached garages can pose a threat to a home’s indoor air quality. Carbon monoxide from internal combustion engines is poisonous at moderate concentrations, and effects from chronic exposure to volatile organic compounds from chemicals such as pesticides, paints, and other frequently garaged items are likely detrimental. These contaminants and their byproducts can migrate across garage house interfaces through bypasses in the structure, or via ductwork or HVAC equipment present in garages. This paper presents results from an ASHRAE-sponsored project on the migration of garage contaminants into the home in five houses in central Illinois with a variety of attached garage configurations.

Different ventilation strategies can have an enormous impact on both exposures to contaminants of concern (COCs) and energy use in commercial buildings. To test various strategies, we implemented two pollutant exposure control strategies in several commercial buildings in the US and the Middle East. Buildings type covered include wellness center/gym, university, office building, and a bank. The first control strategy was the conventional ventilation strategy (conventional mode). The outside air dampers were open according to the design conditions all the time. The second strategy consisted of using air cleaning along with ventilation (air cleaning mode). In each of the buildings tested, we installed a module composed of innovative sorbent materials that can efficiently remove gaseous contaminants of concern. The sorbents employed self-regenerating capabilities. The module is equipped with smart software and set of sensors that actively and automatically manage HVAC load and indoor air quality. The outside damper was set to a minimum position (minimum outdoor air is set to maintain a positive pressure in the building) unless outdoor conditions were favorable (economizer mode). In order to compare energy usage and indoor air quality, we operated the building alternatively in conventional mode and air cleaning mode. For each, we measured electrical and/or thermal energy by installing an energy meter on the air handling units. Also, for each period, we tested speciated VOCs, aldehydes, CO₂, and PM_2.5. The outcomes of these tests showed that using the air cleaning mode - employing a pollutant exposure strategy with air cleaning and minimum ventilation coupled with smart controls - realized double digit energy savings (20-40%) compared to conventional modes, while at the same time maintained or improved the air quality in the space. Formaldehyde is one of the key contaminants that was identified as a COC. Formaldehyde was successfully maintained below 33 ug/m³. For the pollutants measured, we calculated emission rates and gave examples of using time-averaged mass balance equations to show compliance with ASHRAE Standard 62.1 Indoor Air Quality Procedure (IAQP). Field measurements in this study, which compared conventional and air cleaning modes, demonstrated that efficient air cleaning is a superior option delivering both IAQ and energy savings.

The current bio-physical theories of indoor comfort and satisfaction with indoor environmental quality (IEQ), such as thermal and visual comfort adopt an environmentally deterministic perspective that only stresses the importance of the physical environment in the design of an indoor space. This perspective defines indoor environmental quality in terms of separate components, such as visual and thermal comfort that are independent and separate in their effects on the occupant's overall perception of spatial experience. Accordingly, the design of high performance buildings rely on this perspective to engage various consultants in an integrated design practice that aims to achieve a quality environment for the occupants and the planet. By adopting this limited perspective while relying on tools and metric that predict user experiences with limited accuracy, we are stretching the gap between performance prediction and actual performance of buildings. In real settings, especially those designed with green and sustainable objectives, the occupant reacts to the overall ambiance of the environment resulting from the direct as well as the interactional effect of these components in a systemic perspective that is rarely discussed or conceived in the building design process. This paper proposes a systemic approach to conceptualize IEQ in the design as well as the post-occupancy phases of a project. By applying a holistic understanding, the resulting ambience of green buildings is perceived in terms of five sub-systems; thermal, visual, indoor air quality, acoustical, and spatial comfort. To validate this model, 10 different spatial configurations and IEQ design strategies were assessed and measured for a recently completed high-performance building. Evaluations included a comparative analysis of various deign processes , design and simulation tools used, as well as 24 months of post-occupancy field assessments to test successes and failures of the design process Spatial analysis and visualization of IEQ assessments relating the qualitative phenomenological and quantitative performative impacts of the studied spaces on both the place and the people is presented. Its implications on the future design and research of indoor environmental quality and ambience of sustainable buildings is discussed. The hope is to provide a decision support process and lessons for building practitioners, occupants, building owners that would help them prioritize and evaluate green design and IEQ strategies in a comprehensive way, combining this perspective would ensure that we built spaces that are both energy and people conscious.