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

Carbon monoxide is one of the contaminants in homes that engenders the most concern. Programs that evaluate homes spend substantial effort evaluating carbon monoxide. Furnaces, boilers, water heaters, and ovens/ranges are common sources of carbon monoxide in the indoor environment. This paper presents results of carbon monoxide measurements from two studies that looked at homes that underwent energy efficiency upgrades as part of the U.S. Department of Energy’s low-income Weatherization Assistance Program (WAP). In the first study, carbon monoxide was measured in the flues of furnaces, boilers, and water heaters, in the outlets of ovens/ranges, and in the indoor ambient air. Measurements in the appliance combustion gases was done once while at the site, and indoor air measurements were done using dataloggers recording for about one week. In the second study the focus was only on measured indoor ambient air, also with measurements using dataloggers for about a week. The paper also includes a comparison of carbon monoxide before and after retrofits.

Cooking has been identified as a major source of contaminants of concern for health in residential buildings. Cooking pollutants can be significantly reduced by using range hoods that exhaust to outside, and range hoods are required in Indoor Air Qaulity standards, such as ASHRAE 62.2. However, previous field and laboratory studies have shown that the capture efficiency of range hoods varies widely - even at the same air flow. Currently there is no way for standard developers, designers or installers to specify better capture efficiency. Over the past couple of years LBNL has been conducting laboratory experiments to develop a test method to determine capture efficiency for residential range hoods so that they can be tested and labeled. This test method development has been performed in collaboration with a wide range of constituents, including range hood manufacturers, via the development of an ASTM test method based on the LBNL research. This papr summarizes previous capture efficiency experiments and describes the tracer-gas based test method that has been developed. This includes the laboratory testing procedures and test results for several range hoods. In the development of the test method the laboratory experiments included investigations of spatial and temporal variability in tracer gas concentrations. These were used to develop uncertainty analyses for the proposed test method that will be also be presented.

Cooking emissions have long been seen as an odour problem. However recent studies showed that particle matter is the main health risk of indoor air (Logue, 2013) and cooking can be a major source. Research by MacNeill in 50 Canadian dwellings indicated that 16% of the fine dust originates from indoor sources in the summer, increasing to 41% in the winter. Studies on range hood flowrate and design optimisation showed that there could be a signification reduction of PM2,5 due to cooking. Research in Dutch offices has shown that filtration of ambient air can reduce the indoor PM2,5 concentration significantly. This explorative study aims to quantify the exposure to PM2,5 in 4 Dutch dwellings with two different ventilation systems and with or without mitigation actions. With optical particle counters PM2,5 concentrations were determined in the living room/kitchen and a bedroom of 4 dwellings during a week. Two dwellings were ventilated by a natural supply and mechanical exhaust, and the other two with balanced ventilation with heat recovery. One dwelling used a standard G3 filter and the other an M6. In the dwelling with the M6 filter the effect of an optimised range hood was measured. The results of the cases are described in the paper.

As residential building codes and above-code programs move toward tighter homes with whole-house mechanical ventilation the reliability and homeowner use of ventilation systems become extremely important. As an example of building code direction and concerns, implementation of the 2014 Florida Building Code requirements for whole-house mechanical ventilation and air tightness testing were delayed by the state legislature. The 2014 Florida Residential Code requires whole-house mechanical ventilation be provided for any home with tested air leakage, expressed in air changes per hour at 50 Pascals (ACH50), of < 5, which is also the air leakage upper limit. Similar requirements from the IBC are being implemented in other states (air tightness requirements are stricter in cooler climates). Thus in most states that have adopted the IBC, new homes will be required to have mechanical ventilation systems. What happens when a system fails? Do occupants repair it? Are failures a common enough problem that this is a concern? If failures are a problem, are there steps code bodies can take to minimize risk to health and safety? Toward answering the above questions the Florida Solar Energy Center (FSEC), a research institute of the University of Central Florida, conducted a 21-home field study investigating the failure rates of whole-house mechanical ventilation systems installed in Florida homes over the last 15 years (12 of the 21 systems were installed in the last 3 years). Researchers conducted a survey to assess homeowner ventilation system awareness and maintenance practices. They also inspected and tested the ventilation system to assess its operational status, level of ventilation provided and likely reason(s) for any issues discovered. Homeowners surveyed felt ventilation was important for health, but many were unaware of how their ventilation system operated. Testing found only three of the 21 study homes (14.3%) had ventilation air flow close to the design level with the type of system specified. In two of these homes, the ventilation systems were turned off by the homeowner, so only one of 21 homes (4.8%) was actually receiving the expected ventilation as found. Only 12 of the 21 homes (57.1%) were found to have ventilation systems capable of operating. Issues identified included failed controllers and dampers, partially disconnected or crushed ducts, dirty filters, and poor outdoor air intake locations. The paper provides a summary of the study findings along with a discussion of the results and recommendations for improving whole-house ventilation system performance and reliability.

Combustion safety testing standards for residential retrofit have recently changed.  Additionally, there has been substantial alignment between standards and guidelines from different organizations, including NFPA, BPI, and ACCA.  This has been the result of a significant effort to include all stakeholders in the development of the new procedures. The changes have simplified the process while retaining the evaluation of those issues that are most likely to present problems to homes. These changes will impact practices for residential retrofit programs going forward.  This paper describes the changes that have been made, provides the ratiobale for these changes, and details the alignment between organizations that has occurred.  In addition, results from a field study and survey of combustion safety failures in retrofit homes, which were conducted as a part of a Building America project, will be discussed.

Today the U.S. housing industry is at a critical juncture in its ability to deliver homes that safely and effectively meet increasingly demanding performance requirements of homeowners and modern building codes. But the housing industry must learn to better manage real and perceived risks that can impact occupant health and comfort and building durability. It is clear from decades of applied research through the U.S. Department of Energy's (DOE) Building America program that many building energy efficiency and performance improvements will not be adopted by the market or industry standards if they increase the likelihood of IAQ problems. Furthermore, good IAQ and healthy home features have been shown to be powerful drivers for energy efficiency and improved home performance. In 2015, Building America published a new integrated strategy to address these challenges and opportunities. The Building America Research-to-Market Plan, including three integrated Building America Technology-to-Market Roadmaps, will guide Building America’s RD&D activities over the coming years, to tightly focus program efforts on solving three critical challenges, and on improving the ability of the housing market infrastructure to adopt innovations that address them. The three Building America Roadmaps include: A) high-performance, moisture-managed envelope solutions; B) optimal comfort systems for low-load homes; and C) optimal ventilation and Indoor Air Quality (IAQ) solutions (the “IAQ Roadmap”). This paper describes the Building America IAQ Roadmap in more detail and highlight progress to date. This roadmap seeks to guide RD&D and market engagement to ensure that the development of best practices, specifications, and improved industry standards (e.g., future editions of ASHRAE 62.2) account for the effects that the building and its systems may have on the health of occupants and the durability of the building, while minimizing energy usage. The roadmap provides detailed strategic objectives that focus on improving technologies and industry standards in three areas: 1) Targeted pollutant solutions that better control known indoor contaminants of concern, near their emission source(s), to allow for improved IAQ without increasing dilution ventilation requirements; 2) Smart ventilation technology solutions that optimize the balance between IAQ and energy and account for other variables that affect IAQ, such as occupancy, exhaust fan (e.g., dryer and range hood) operation, indoor and outdoor temperature, RH, and outdoor pollutant levels (e.g., ozone and particles); and 3) IAQ valuation that facilitates standardized, quantified assessments of home IAQ to encourage more informed and objective design decisions regarding IAQ measures.