Removing Smoke from Nepali Kitchens by K M Sulpya
Energy conservation - especially in the context of rural energy
demand management is crucial in Nepal, where fuelwood is the major source of
energy. Emphasis on sustainable fuelwood use is the prime requirement.
Programmes on improved cookstoves (ICS) have been launched and promoted in an
attempt to facilitate fuelwood conservation.
Stove for cooking injera
The main objectives of stove programmes in Nepal are to develop
and disseminate improved cookstoves that reduce both fuel consumption and the
level of noxious gases that contaminate households. Smoke is a major problem for
women and their families. Studies and test results show that respiratory
illnesses are the major contributor to infant mortality in Nepal. So far, more
than 60,000 ICS have been disseminated, but the exact number in use is unknown.
At the beginning of the project, a study was undertaken to
determine what type of stove was used and what extension strategy was necessary
for dissemination. Traditionally women cook on semienclosed chulos or on open
fires' The size of the kitchen, its position in the house, the ventilation area,
and the number of fireplaces and kitchens in a particular household vary widely
throughout the country. In some areas the fire is also used to provide heat and
light. Among some ethnic groups the cooking is a religious ritual.
Carbon monoxide emissions
To test the levels of noxious smoke given off by different cooking
systems, carbon monoxide measurements were taken with open fires, semi-enclosed
chulo, and improved cookstoves with chimneys, by using a portable carbon
monoxide analyzer (capable of reading to an accuracy of 0.01% CO). Room volume,
areas of windows and doors, and dimensions of the ICSs and other stoves were
recorded. The test results listed in Table I show that carbon monoxide emissions
are significantly lower for a properly installed ICS compared to either the
traditional stove or the medium or badly installed ICS. It is also apparent that
there is a much lower variance in the emissions from the well installed ICS.
This indicates clearly that a well-installed ICS coupled with a chimney can
reduce smoke in the kitchen.
Chimney construction and installation problems
Chimneys built from blocks of mud formed in wooden moulds are made
in Nepal villages. During transportation to the project areas many chimneys are
cracked and broken. Most stove organizations face problems with chimney
installation. The project has to pay for the construction and installation. In
poor houses with thatched roofs and wooden wails, chimney installation is very
difficult and extra care should be taken. Chimneys less than four to five feet
high cause low draughts, and the second cooking pot does not get enough heat
this is one of the reasons people abandon ICS. Most of the houses in Nepals
hills and mountains are made from stone. Knocking out a hole in the wall for the
chimney outlet is difficult and time consuming. Lack of confidence and limited
skill; restrict women's involvement in chimney construction. The study found
that most chimneys are incorrectly installed at a right angle to the wall,
causing another draught problem. Some installers found making a hole in a
slanting position for the chimney outlet difficult when there are big stones in
the wall. Upper floor chimneys are even more difficult to install securely.
Table 1: Average carbon monoxide emissions from different stoves
Chulo (traditional mud stove)
Ageno (open fire)
ICS with chimney (well installed)
ICS with chimney (fairly well installed
ICS with chimney (badly installed)
Chimney maintenance is a real problem. In Nepal, people,
particularly those from higher castes, have assumed that it is the installers
job to clean and maintain the stoves. Where there are no cleaners, chimney and
stove maintenance and performance is low. Sometimes, bad installation, neglect
of the stove, or failure to clean the chimney results in sparks leaving the
chimney and igniting the roof thatch.
Although most stove organisations in Nepal favour chimney stoves
because they are effective in removing smoke but these stoves do not necessarily
save fuel. Incorrectly designed chimneys, or failure to use dampers cause
excessive fuel consumption or poor combustion.
Construction of inefficient 'look-a-like' copies of ICS with
chinmeys was observed in Surkhet district. The installers and the organizations
were unaware of the critical technical parameters that must be observed.
Evaluation shows that these stoves consume more fuel that traditional stoves.
However, well-designed, well-installed and well maintained chimney
stoves do perform better, and do save fuelwood. Studies proved that fuel
efficiency was 21 to 25 per cent. Inadequate training, bad installation and poor
maintenance are the major causes of the failure of past cookstove programmes in
Between 1984 and 1985, RECAST started to commercialize pottery
stoves in Kathmandu. Stove. together with chimneys were marketed and about
thirty were sold. Shop-keepers then refused to sell the stove because of the
need to stock so many parts keep the parts outside the shop, and to show buyers
how to put together all the chimney parts. If one piece is broken, there is a
delay until the potters car deliver again. In addition, the cost of a chimney is
double the cost of a stove. This affects the 'payback period and the stoves
affordability. Metal chimneys cost more than twice the price of the stove and
are too expensive for the rural Nepali as well as being difficult to use.
Mud blocks, produced by family members with wooden mould can be
used successfully to build chimneys (see figure 2). Mud-brick chimneys in
exposed positions can be damaged by rain and may allow water to leak into the
stove. To tackle this a few organizations have built chimney caps to give
protection from wind and rain (see figure 3). In the Kathmandu valley stoves are
installed on the top floors of houses, with a special smoke removal hole in the
roof about 1.5 feet in diameter, and a rain protection cover. In urban and
semiurban areas, a chimney hood is used for smoke removal.
The ICS being introduced in Nepal is a chimney stove. During the
winter however, most people use both a traditional open fire and an ICS for
heating. The open fire is used for cooking animal feed and so the stove chimney
only removes about 30 per cent of the total smoke produced.
Work in Nepal will continue with the introduction of portable,
improved stoves installed in well ventilated kitchens and with smoke removal
hoods and chimneys such as those being developed by ITDG in Kenya or with
'cooking windows' (hoods and chimneys built into the walls) now being
demonstrated by the Hanoi Architect Institute in Vietnam (see page 22). For more
details of the ICS programme see GLOW, Vol 11, March 1 994.
K M Sulpya, Research Centre for Applied Science and Technology,
(RECAST) Tribhuvan University, Kirtipur, Kathmandu,