United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S7-90/004 May 1990
Project Summary
Characterization of Population
and Usage of Unvented
Kerosene Space Heaters
J. Barnes, P.Holland, and P. Mi hi master
Indoor air quality is affected by a
number of synergistic factors,
including combustion emissions from
unvented appliances. Unvented
kerosene space heaters (UKSHs) can
be a significant source of such
emissions. To gather baseline
information to help assess the
magnitude and potential severity of
this problem, this study investigated
the market penetration of UKSH in the
residential sector. UKSH usage
patterns were also investigated.
UKSH technology is fast evolving,
and a common technical
nomenclature is difficult to define.
Many individual manufacturers
employ their own terminology, Most
units are characterized by heat
transfer mechanism (convective or
radiant), flame type (blue or white),
and combustion mechanism (single
or dual stage combustion and wick-
fed or wickless). There are many
variations and combinations.
Annual sales of UKSHs are
estimated at 825,000 units. Leading
brands include convective units
marketed by Toyotomi USA (Kero-
Sun) and Corona USA. Some units
contain built-in catalytic filters for
odor control. Add-on catalytic filters
are available from at least one
manufacturer.
It is believed that 15-17 million
portable UKSHs have been sold in the
U. S. since the early 1970s. However,
it is estimated that in the 1986-1987
heating season, there were only
about 7 million units in use. About
half of these units are in the South.
Depending on whether UKSHs are
used as primary or secondary
heating sources, they may be used
anywhere from 2 to 17 hours per day.
Eighty percent of UKSHs are used in
multi-family dwellings and mobile
homes. While the number of UKSHs
is fairly evenly distributed across
income class, most kerosene
consumption is among the lower
income groups (a small amount of
this kerosene consumption may be
used in heating equipment other than
UKSHs).
Literature abstracts of publications
relating to UKSH use and emissions
are in report Appendix B . Based on
the predominance of UKSH use in
multi-family dwellings and mobile
homes, further study of these sectors
is suggested to more specifically
define usage characteristics.
This Project Summary was
developed by EPA's Air and Energy
Engineering Research Laboratory,
Research Triangle Park, NC, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
, This study had. a research objective
and an operational objective. The
research objective was to describe
unvented kerosene space heater (UKSH)
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technology, and to develop estimates of
market penetration and usage
characteristics. The operational objective
was to develop recommendations for
specific UKSHs to be laboratory tested
for emissions. These recommendations
were to be based on sales trends for
recent/current models, and for future
models.
With respect to the research objective
of this study, the following conclusions
can be drawn:
•In the 1986-1987 heating season,
there were an estimated 7 million
UKSHs in use in the United States.
• Depending upon whether used as a
primary or secondary heating source,
and geographic location, it is
estimated that UKSHs are operated
from 2 to 17 hours per day.
•Eighty percent of kerosene
consumption is in multi-family
dwellings and mobile homes,
although not all of this consumption
is in UKSHs.
•Kerosene usage for space heating is
generally concentrated in the lower
income groups.
•Some units are marketed with built-in
catalytic filters for odor control, and
add-on catalytic devices are available
from at least one manufacturer.
However, industry sources contend
that future efforts will be focused on
better combustion design, rather than
post-combustion catalytic controls for
reducing emissions.
•The literature reviewed for this study
shows that UKSHs can be a
significant source of indoor air
pollutants, including certain organic
compounds which may be
carcinogenic.
As representative of recent/current
best selling models of UKSHs, the
authors recommend the Kero-Sun Omni-
105, an omnidirectional convective unit
marketed by Toyotomi USA, and the
Corona 22DKC, an omnidirectional
convective unit marketed by Corona
USA. The third best-selling unit is
believed to be the Robeson 03-2619-91,
a directional radiant unit marketed by
Robeson Industries. These basic models
are expected to remain big sellers over
the next several years.
Representative of models which may
see increased sales in the future are the
Toyostove Double Clean 100 and the
Toyostove Laser Clean LR450, both
marketed by Toyotomi USA. The former
represents an advanced technology for
UKSHs known as dual or. two-stage
combustion. The latter represents the
newer "wickless" technology.
Based on the above findings, several
areas are identified which may require
further research: use of UKSHs in mobile
homes and multifamily buildings,fuel
quality issues, synergistic effects of
unvented kerosene combustion and
combustion of other appliances, and a
survey of kerosene households to
examine usage patterns.
Use of UKSHs in Mobile Homes
According to initial estimates based on
consumption patterns, about 33% of
UKSHs are used in mobile homes.
Evidence ..indicates, that mobile homes.
particularly those constructed after 1974
when new standards went into effect,
may be substantially "tighter" than
standard single family dwellings. This is
based on better quality control for
factory-built housing. Lower infiltration
rates in mobile homes coupled with
unvented kerosene combustion could
lead to substantially higher levels of
indoor air pollutants in mobile homes..A
complicating factor is that UKSHs often
may be the primary heating source in
mobile homes (given their reduced
square footage) and thus could be
operated as much as 17 hours per day
on average. Further, mobile homes are a
fast growing segment of the housing
market, and many have relatively high
proportions of infants and the elderly
susceptible subpopulations. The authors
recommend a research effort to measure
infiltration rates in typical mobile homes
(both pre- and post-1974) and better
define the saturation and usage patterns
of UKSHs in mobile homes. Growth rates
and occupancy patterns should also be
examined; = '—
Use of UKSHs in Multifamily
Buildings
Initial estimates indicate that fully 47%
of UKSHs may be used in multifamily
dwellings. Most research to date on
emissions has concentrated on single
family dwellings, yet the standard single
family dwelling sector only accounts for
an estimated 20% of households using
UKSHs. Further, preliminary evidence
exists which indicates a wide degree of
variability in infiltration rates in multifamily
buildings. The major reasons are
exposure and stack effects. While single
family buildings typically have four
exterior walls, apartments in multifamily
buildings may have only one exterior
wall. Limited measurements indicate that
an apartment ori the leeward side of a
multifamily building may have infiltration
rates only slightly above zero air changes
per hour,(ACHs),although this may only
be a transient situation. Use of an UKSH
in such an apartment could periodically
lead to very high levels of pollutants.
Health effects are complicated by the fact
that many apartment dwellers may
include susceptible subpopulations such
as the elderly and infants. The authors
recommend an effort to better define the
saturation, usage patterns, and
occupancy characteristics of UKSH
usage in multifamily dwellings. This
should be coupled with an emissions
characterization which includes testing in
multifamily building environments. ...
Fuel Quality Issues
K-1 is the recommended kerosene fuel
for most UKSHs. K-2 is a somewhat
"dirtier" fuel which is also widely
available. Since K-2 is usually slightly
cheaper than K-1, some individuals may
be tempted to use K-2 in their UKSHs.
This could lead to higher emission rates
for certain pollutants. Note that" this
problem is not limited to willful misuse by
the consumer. There have been
documented cases of K-2 kerosene's
being labeled and sold as K-1 kerosene
by dealers. The magnitude and severity
of this problem is unknown. The authors
suggest a limited effort be undertaken to
examine this issue. This would include
random spot sampling of kerosene
offered for sale to determine fuel quality
coupled with characterization of the
emissions of UKSHs when combusting K-
2 kerosene.
Synergistic Effects of Unvented
Kerosene Combustion and
Go m b u s t i o n o f Other
Appliances
UKSHs may be used in conjunction
with unvented gas appliances, such as
gas cooking stoves. While numerous
experiments have been conducted for
criteria pollutants, only limited work has
been done to explicitly measure the
interactive effects of gas and kerosene
combustion for non-criteria pollutants
(e.g., PAHs). It is suggested that a limited
effort be undertaken to characterize the
interactive effects. If this results in
concerns, further analysis could attempt
to estimate the population of households
where both unvented kerosene and gas
appliances are in use.
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Survey of Kerosene
Households to Examine Usage
Patterns
This study has estimated usage
patterns for UKSHs based on total
kerosene consumption estimates. To
better understand actual usage and
behavior patterns, it is important to
survey users to gauge variables such as
number of hours of operation per day,
age and health of building occupants,
number of units in use, location of units,
and whether or not supplemental heating
is used. To accomplish this, a limited
survey of kerosene heater users would
be necessary. The suggested approach
would be to "piggy back" on existing
residential energy surveys such as those
conducted by the U.S. Energy
Information Administration, where a
secondary survey would be administered
to respondents having identified
themselves as UKSH users..
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J.Barnes, P.Holland, and P.Mihlmester are with Applied Management Sciences,
Inc., Oak Ridge, TN 37830..
James B. White is the EPA Project Officer (see below)..
The complete report, entitled "Characterization of Population and Usage of
Unvented Kerosene Space Heaters," (Order No. PB 90 155 573/AS; Cost:
$17.00 , subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use S300
EPA/600/S7-90/004
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