Building codes increasingly require tighter homes and mechanical ventilation per ASHRAE Standard 62.2. These ventilation flows must be measured so that energy is not wasted with over ventilation and occupants' health is not compromised by under ventilation. Flow hoods are used to measure these ventilation flows, but there is currently no standard specifying the measurement procedure and measurement devices that should be used. This study evaluates the accuracy of six commercially available flow hoods under laboratory conditions configured to emulate a residential mechanical ventilation duct system. The measurements taken with the flow hoods were compared to simultaneous measurements taken by an in-line reference flow meter having a known uncertainty. Results indicate that powered flow hoods yield more accurate measurements than non-powered flow hoods, and that a majority of the flow hoods measured inlet flows more accurately than outlet flows. In several cases, there was little resemblance between the manufacturers' stated accuracy and the accuracy we found in our laboratory measurements. It is clear that current flow hood calibration procedures may not consider field application variables such as flow asymmetry, flow angle, and flow direction. A new flow hood measurement standard that takes these 'real world' conditions into account should be developed to ensure that residential buildings receive the intended ventilation flows.4

Cooking and cooking burners emit pollutants that can adversely affect indoor air quality in residences and significantly impact occupant health. Effective kitchen exhaust ventilation can reduce exposure to cooking-related air pollutants as an enabling step to healthier, low-energy homes. This report identifies barriers to the widespread adoption of kitchen exhaust ventilation technologies and practice and proposes a suite of strategies to overcome these barriers. The recommendations have been vetted by a group of industry, regulatory, health, and research experts and stakeholders who convened for two web-based meetings and provided input and feedback to early drafts of this document. The most fundamental barriers are (1) the common misconception, based on a sensory perception of risk, that kitchen exhaust when cooking is unnecessary and (2) the lack of a code requirement for kitchen ventilation in most US locations. Highest priority objectives include the following: (1) Raise awareness among the public and the building industry of the need to install and routinely use kitchen ventilation; (2) Incorporate kitchen exhaust ventilation as a requirement of building codes and improve the mechanisms for code enforcement; (3) Provide best practice product and use-behavior guidance to ventilation equipment purchasers and installers, and; (4) Develop test methods and performance targets to advance development of high performance products. A specific, urgent need is the development of an over-the-range microwave that meets the airflow and sound requirements of ASHRAE Standard 62. Executive SummaryCooking and cooking burners can emit combustion products, pollutants and excess moisture that may adversely impact indoor air quality in residences. Cooking-related contaminants include but are not limited to carbon monoxide, nitrogen dioxide, formaldehyde, volatile organic compounds, polycyclic aromatic hydrocarbons, fine particulate matter, and ultrafine particles. People present in a home during cooking can perceive odors, smoke, and dampness, but the level of concern about these cooking-related contaminants varies. People cannot directly detect or assess the quantity of pollutants in the air and many are unaware that cooking and cooking burners produce health-relevant pollutants. As a result, use of kitchen ventilation is inconsistent even when it is available, and efficacy is not a strong market driver for kitchen designs or ventilation products.Recent research indicates that cooking-related pollutants have a greater impact on health, safety and indoor air quality than had previously been recognized, and for this reason should now be given more serious attention.Few US states have mandatory codes or standards relating to kitchen ventilation. As a result, many homes have been built and are being built today without any kitchen ventilation. Even in homes that have kitchen ventilation, the systems may not be very effective owing to a variety of factors. Capture efficiencies of 100% are possible with a well-designed exha...

In many residential building retrofit programs, air tightening to increase energy efficiency is constrained by concerns about related impacts on the safety of naturally vented combustion appliances. Tighter housing units more readily depressurize when exhaust equipment is operated, making combustion appliances more prone to backdraft or spillage. Several test methods purportedly assess the potential for depressurization-induced backdrafting and spillage, but these tests are not robustly reliable and repeatable predictors of venting performance, in part because they do not fully capture weather effects on venting performance. The purpose of this literature review is to investigate combustion safety diagnostics in existing codes, standards, and guidelines related to combustion appliances. This review summarizes existing combustion safety test methods, evaluations of these test methods, and also discusses research related to wind effects and the simulation of vent system performance. Current codes and standards related to combustion appliance installation provide little information on assessing backdrafting or spillage potential. A substantial amount of research has been conducted to assess combustion appliance backdrafting and spillage test methods, but primarily focuses on comparing short-term (stress) induced tests and monitoring results. Monitoring, typically performed over one week, indicated that combinations of environmental and house operation characteristics most conducive to combustion spillage were rare. Research, to an extent, has assessed existing combustion safety diagnostics for house depressurization, but the objectives of the diagnostics, both stress and monitoring, are not clearly defined. More research is also needed to quantify the frequency of test "failure" occurrence throughout the building stock and assess the statistical effects of weather (especially wind) on house depressurization and in turn on combustion appliance venting. Incorporating weather variations and house ventilation system characteristics in existing simulation software may assist such analyses and with developing a more reliable diagnostic for use on-site.

Cooking and cooking burners emit pollutants that can adversely affect indoor air quality in residences and significantly impact occupant health. Effective kitchen exhaust ventilation can reduce exposure to cooking-related air pollutants as an enabling step to healthier, low-energy homes. This report identifies barriers to the widespread adoption of kitchen exhaust ventilation technologies and practice and proposes a suite of strategies to overcome these barriers. The recommendations have been vetted by a group of industry, regulatory, health, and research experts and stakeholders who convened for two web-based meetings and provided input and feedback to early drafts of this document. The most fundamental barriers are (1) the common misconception, based on a sensory perception of risk, that kitchen exhaust when cooking is unnecessary and (2) the lack of a code requirement for kitchen ventilation in most US locations. Highest priority objectives include the following: (1) Raise awareness among the public and the building industry of the need to install and routinely use kitchen ventilation; (2) Incorporate kitchen exhaust ventilation as a requirement of building codes and improve the mechanisms for code enforcement; (3) Provide best practice product and use-behavior guidance to ventilation equipment purchasers and installers, and; (4) Develop test methods and performance targets to advance development of high performance products. A specific, urgent need is the development of an over-the-range microwave that meets the airflow and sound requirements of ASHRAE Standard 62. Executive SummaryCooking and cooking burners can emit combustion products, pollutants and excess moisture that may adversely impact indoor air quality in residences. Cooking-related contaminants include but are not limited to carbon monoxide, nitrogen dioxide, formaldehyde, volatile organic compounds, polycyclic aromatic hydrocarbons, fine particulate matter, and ultrafine particles. People present in a home during cooking can perceive odors, smoke, and dampness, but the level of concern about these cooking-related contaminants varies. People cannot directly detect or assess the quantity of pollutants in the air and many are unaware that cooking and cooking burners produce health-relevant pollutants. As a result, use of kitchen ventilation is inconsistent even when it is available, and efficacy is not a strong market driver for kitchen designs or ventilation products.Recent research indicates that cooking-related pollutants have a greater impact on health, safety and indoor air quality than had previously been recognized, and for this reason should now be given more serious attention.Few US states have mandatory codes or standards relating to kitchen ventilation. As a result, many homes have been built and are being built today without any kitchen ventilation. Even in homes that have kitchen ventilation, the systems may not be very effective owing to a variety of factors. Capture efficiencies of 100% are possible with a well-designed exha...

Beginning with the 2008 version of Title 24, new homes in California must comply with ANSI/ASHRAE Standard 62.2-2007 requirements for residential ventilation. Where installed, the limited data available indicate that mechanical ventilation systems do not always perform optimally or even as many codes and forecasts predict. Commissioning such systems when they are installed or during subsequent building retrofits is a step towards eliminating deficiencies and optimizing the tradeoff between energy use and acceptable IAQ. Work funded by the California Energy Commission about a decade ago at Berkeley Lab documented procedures for residential commissioning, but did not focus on ventilation systems. Since then, standards and approaches for commissioning ventilation systems have been an active area of work in Europe. This report describes our efforts to collect new literature on commissioning procedures and to identify information that can be used to support the future development of residential-ventilation-specific procedures and standards. We recommend that a standardized commissioning process and a commissioning guide for practitioners be developed, along with a combined energy and IAQ benefit assessment standard and tool, and a diagnostic guide for estimating continuous pollutant emission rates of concern in residences (including a database that lists emission test data for commercially-available labeled products).