Tobacco specialists and county agents throughout the flue-cured production area now have a means of assisting growers who are concerned about possible cracked or leaking heat exchangers.
"Heat exchangers were installed in U.S. curing barns three years ago to contain and redirect outside the barn the combustion exhausts of fuels used to cure tobacco. These exhausts contain carbon dioxide (CO2), nitrous oxides and other gases," says University of Georgia Extension tobacco specialist J. Michael Moore.
Numerous CO2 meters, says Moore, have been placed in all five flue-cured states, and agents are receiving training to use these meters to check the integrity of heat exchangers.
When CO2 levels increase inside the curing chamber during testing, leaks in the heat exchanger and exhaust stack assemblies are indicated, he explains. Presence of C02 also indicates the presence of nitrus oxides and the potential for the formation of nitrosamines during the curing of flue-cured tobacco.
"Once increases of CO2 are identified, growers can closely inspect each heat exchanger unit under bright lighting for stress cracks in the metal or welds, and at the junction of the heat exchangers and the exhaust stack," says Moore.
Under the guidelines of the program which required retrofitting of U.S. barns, manufacturers of the heat exchangers were required to warranty these units for a minimum of three years. Growers will want to work directly with the manufacturer of their heat exchangers if problems occur, advises Moore.
Growers who want their curing barns evaluated for CO2 leaks should contact their county Extension agent. C02 meters in Georgia are being placed in key counties and are available for use by agents in surrounding counties.