ASHRAE Journal - October 2010 - 76

iaq applications	

iaq & High performance
S
By andrew K. persily, ph.D., Fellow	ASHRAE; and steven J. Emmerich, Member	ASHRAE

ince	the	energy	crisis	of	the	1970s,	much	has	been	learned	about	 decisions are made without an understanding of the potentially serious consequences well-established body of knowledge on The impacts of IAQ on occupant health

how	to	improve	energy	efficiency	in	buildings.	More	recently,	given	 of poor IAQ and without the benefit of the

increases	in	energy	costs	and	concerns	about	the	environmental	impacts	of	 how to provide good IAQ.12

buildings,	there	has	been	renewed	emphasis	on	reducing	building	energy	 and comfort, which serve as the bases of 13 consumption.	Over	the	same	time	period,	there	has	also	been	increasing	 ASHRAE Standard 62.1, are determined awareness	of	indoor	air	pollution	as	a	significant	human	health	issue.	
The building community is challenged to reduce the environmental impacts of buildings, including energy consumption and greenhouse gas emissions, while maintaining indoor environments that are conducive to occupant health and comfort. A number of programs, standards, codes and other efforts are promoting, and in some cases requiring, the design and construction of green or sustainable buildings.1–4 More recently, there has been a focus on net zero energy buildings.5 Some of these discussions also speak to high performance, which generally includes a range of non-energy issues such as indoor air quality (IAQ). Nevertheless, most discussions of sustainable, high performance buildings tend to focus on energy, which while critically important, is only one aspect of performance and should not be pursued to the neglect of the others. This article considers the role of IAQ in energy-efficient buildings and discusses how good IAQ can, and should be, factored into energy efficiency and other sustainable building goals. typical buildings. The connection of IAQ and ventilation to occupant health and performance has been noted previously, including in the report of the 2005 Surgeon General’s Workshop on healthy indoor environments6 and in key EPA publications.7,8 These documents note the importance of good IAQ in achieving high performance buildings as well as the need to consider the IAQ impacts of building energy-efficiency strategies. IAQ has long been known to affect occupant health, comfort and productivity.9 Well-established, serious health impacts resulting from poor IAQ include Legionnaires’ disease, lung cancer from radon exposure, and carbon monoxide poisoning. More widespread health impacts include allergy and asthma from exposure to indoor pollutants (particularly those associated with building dampness and mold), colds and other infectious diseases that are transmitted through the air,10 and “sick building syndrome” symptoms. These more widespread health outcomes affect large numbers of building occupants and are associated with significant costs due to health care, sick leave and lost productivity. Fisk11 estimates that potential cost reductions from providing better IAQ in non-industrial U.S. workplaces could be tens of billions of dollars annually. Despite these significant impacts, many building design and construction
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iaq in High performance Buildings

One of the most important functions of buildings is to provide a place for people to live, work and learn. Energy-efficient, high performance buildings arguably should improve occupant health, comfort and productivity relative to more
76	 ASHRAE	Journal	

by indoor contaminant levels. However, the large number of indoor contaminants, variations in individual susceptibility, and the lack of guideline or regulatory levels for the majority of contaminants make it impossible to define IAQ performance in terms of concentrations. Occupant questionnaires that evaluate the acceptability of IAQ within a space are another means of assessing IAQ,14 but these tools have not been standardized and do not address health impacts, particularly from contaminants that are not perceived by building occupants at low concentrations. Given the inability to relate quantitative IAQ parameters to occupant health and comfort, IAQ performance requirements are necessarily based on exercising good practice in building design, construction and maintenance, which is the approach taken in the IAQ Guide recently published by ASHRAE.12 Good practice includes providing adequate levels of ventilation with clean outdoor air, keeping buildings clean and dry, designing buildings to facilitate good operations and maintenance (O&M), and controlling indoor sources through material selection, source isolation and other means. Given the challenge of defining IAQ performance, the definition of IAQ criteria for high performance buildings is not at all straightforward. However, it seems clear that IAQ goals in high performance buildings should go beyond the minimum requirements of building codes and standards such as Standard 62.1. As noted
	 October	 2010
ASHRAE Journal - October 2010

Table of Contents for the Digital Edition of ASHRAE Journal - October 2010
