ARC mission includes developing the tools necessary to bring appropriate technology to people in need. Over the last few years ARC and other Testing Centers have worked to improve the ability to test stoves with chimneys for both the emissions that are taken out of the house and those that contribute to indoor air pollution. Continue reading to learn more about testing chimney stoves.
The IWA testing procedure contains two categories of emissions metrics, total and indoor. For stoves without a chimney the results for indoor emissions can be calculated from the results for total emissions and an assumed air exchange rate/size of room. For stoves with a chimney the indoor emissions must be measured directly. In this case the indoor emissions are those that escape through the fuel entrance of the stove, the body of the stove and any other leaks before the chimney passes through the envelope of the house. These are known as fugitive emissions. The total emissions equal the fugitive emissions plus the emissions that exit through the chimney.
The LEMS hood specifications have been modified to include a second floating hood that is placed above the primary hood. A diagram is shown below. A bypass for the chimney is installed in the primary hood so that the emissions from the chimney are brought into the second hood. This second hood goes to a “T” where the gasses can be directed outside of the building or to the sensor box. With the gate valve A open and gate valve B closed only fugitive emissions will be sampled. With gate valve A closed and gate valve B open total emissions will be sampled. Tests for total and fugitive emissions are done independently and without having to move the stove.
The WBT Sensor Box Processing Spreadsheet is being developed to more easily manage data from chimney stove tests, but in the mean time instructions are available for using the GACC WBT spreadsheet.
Aprovecho Research Center
PO Box 1175
Cottage Grove, OR 97424, USA