Below is an article from Garn's website that talks about the EPA vs ASTM test protocol. It's good basic information and touches on the major difference between testing with cordwood vs sawn and cribbed wood. If you want to see the pictures you can go to www.garn.com and have a look. They wouldn't copy & paste here and my limited computer skills prohibit me from attaching them. Martin Lunde GARN EPA TESTING Part 3 Last month I asked you to think about the following: * Is the ASTM test method generally a more accurate predictor of field performance than the EPA method? * How does this affect GARN WHS products? As stated last month, crib wood requires significantly more secondary air for "clean combustion" than cordwood. So how does an EPA Phase II listed OWB actually perform in the field with cordwood, after having passed the EPA emissions test utilizing EPA required crib wood? Pictured below is an operating EPA Phase II certified unit: This unit is in its second winter of operation and is located in Alaska. 0549I Pictured below is the combustion chamber loaded with cordwood. Note the volume of creosote on the combustion chamber surfaces and door: #2 Pictured below is the flue of this unit. Notice the creosote on the exterior of the flue. flue wirh creosote on Pictured below is a 25 year old operating GARN WHS 500 unit that is not EPA Phase II certified. Notice the lack of creosote and lack of smoke rolling out of the loading door. #4 This is the flue of the operating GARN WHS 500 unit....note the clear exhaust. This horizontal flue installation does not comply with the GARN Installation Manual specifications. #5 Pictured below is a 2 year old operating GARN WHS 1500 unit. Again note the clear exhaust except for water vapor. Canadian Flag Here is the combustion chamber and door. Note the lack of creosote and lack of smoke rolling out of the loading door. #7 All models of the GARN product line have been developed utilizing cordwood because our customers use cordwood. GARN WHS equipment could be modified to pass the EPA Phase II test protocol utilizing crib wood; however, when operated utilizing cordwood the GARN WHS units would produce more emissions due to the excessive secondary air supply dictated by the crib wood test fuel. No one that I know burns sanitized crib wood in their GARN unit. GARN WHS equipment will be tested in accordance with Appendix XI of ASTM Document E 2618 - 09 utilizing cordwood. It is very important to note that this document in its entirety requires "Test fuel charge fuel shall be white or red oak cordwood 18 to 28 % moisture content-dry basis.." Oak isone of the most common cordwood fuels available and used in the United States. Not only is this test fuel a logical choice, it has also been proven to be a reliable test fuel that produces statically consistent results. The goal of the EPA Phase II voluntary standards is cleaner burning wood heating equipment. This is a good goal because it will clear the air of excessive OWB emissions. However, the ASTM test method is a much better indicator of real world in field performance than any test method that utilizes crib wood as the test fuel. It is interesting to note that European test protocols also require cordwood and NOT crib wood. The EPA needs to modify its test protocol and specify cordwood as the required test fuel in lieu of crib wood. Presently many states are set to adopt the EPA Phase II voluntary standards and totally miss the primary objective of the standard.....cleaner air. However, if a sufficient number of concerned citizens' contact their local and state Representatives, this process can be changed. Cleaner air cannot be obtained by utilizing an inappropriate test fuel. The ASTM test method is the preferred method; moreover, the EPA could simply specify this method as it stands without modification.