ASHRAE Journal - April 2013 - 66

iaq applications
lights. There are, however, several recommendations regarding
research, which could potentially lead to further recommendations. These research recommendations include disaggregating
the IAQ impact of the cooking process from the fuel combustion;
determining emissions from modern units; and evaluating the
difference between the impacts of ovens vs. rangetop burners.
Gas/Propane Heaters
The document has two positions regarding appliance selection. These include that appliances without oxygen depletion
sensors (ODS) should not be used and that any appliance that
is used should be listed to ANSI Standard Z21.11.2. There
are three research needs identified, which could inform future positions. These include evaluating the suitability of the
nitrogen dioxide thresholds in the ANSI appliance standard;
measuring the nitrogen dioxide levels in homes using units
manufactured since 2005 when the nitrogen dioxide emissions requirements went into enforcement; and measuring
particle emissions.
Kerosene/Denatured Alcohol Appliances
Due to the lack of research information available, the position
document simply states that any kerosene or denatured alcohol

appliances should be listed to the relevant standard (UL 647
for kerosene, UL 1370 for denatured alcohol), and that further
installations should be avoided until such time as research
demonstrates the safety of these appliances.
Standards
There are three positions taken with regard to standards.
One is that appliance standards should be reviewed in light
of recently published standards on nitrogen dioxide, most
prominently the new EPA standard for outdoor air. The second
is that heating appliance standards should be reviewed regarding carbon monoxide in light of evidence in field research that
extended continuous use (one hour or more) is not uncommon.
The third is that ventilation standards should include unvented
combustion in their scopes and set appropriate requirements.
This has led to a change proposal in ASHRAE Standard 62.2
to include unvented combustion in the scope; this proposal is
currently working its way through the public review process.
Public Awareness
The document takes two positions with regard to public
awareness. One is that a public education program should be
developed to reinforce the information regarding health and
safety in industry literature. The second is that those who wish
to minimize the risk of adverse health effects due to combustion products should not use unvented combustion appliances.

Summary
ASHRAE’s position document on unvented combustion and
IAQ covers a range of issues and appliance types. It is based
on those research results that are available and identifies gaps
in the knowledge base. It takes meaningful positions based on
the current knowledge regarding potential improvements in
appliance standards and recommendations as well as ventilation standards. While it is not expected that this position document will settle the debate on these appliances, it is a valuable
resource regarding what is known about these appliances and
what measures should be taken to minimize the risk from exposure to combustion products. The position document can be
downloaded for free on ASHRAE’s website at http://tinyurl.
com/az9dvk2.

References
1. Francisco, P.W., J.R. Gordon, B.Rose. 2010. “Measured Concentrations of Combustion Gases from the Use of Unvented Gas
Fireplaces.” Indoor Air 20(5):370–379.
2. Whitmyre, G.K., M.D. Pandian. 2004. “Probabilistic assessment
of the potential impacts of vent-free gas products on indoor relative
humidity.” Building and Environment 39:1179-1185.
3. Hedrick, R.L., E.K. Krug. 1995. “Conventional Research House
Measurements of Emissions from Unvented Gas Space Heaters.” Gas
Research Institute Topical Report, GRI-95/0205.

www.info.hotims.com/44631-27

ASHRAE Journal

Paul Francisco is a research engineer at the University of
Illinois at Urbana-Champaign. Francisco is vice-chair of SSPC
62.2 and is a member of the Environmental Health Committee.
April 2013

ASHRAE Journal - April 2013

Table of Contents for the Digital Edition of ASHRAE Journal - April 2013