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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>Dear Kevin<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>I would like to add that using a fan will in all likelihood create much more flyash than without one. The advantage of a chimney is that the tends to suck the ash up the chimney, whereas a fan tends to blow it up from below into whatever outlet it can find. The difference in the room will be large, obviously.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>Secondly the size of the PM matters a lot. If the pyrolysis process releases very fine siliceous matter with a gentle push from a fan, that material can easily rise through the fuel bed.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>So we should be investigating size, total mass, chemical composition and whether the stove draws it from the stove and room or pushes it up from below.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>Maybe it is of no consequence at all, maybe it is a hazard.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>Regards<br>Crispin<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Dear Rebecca</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Firstly, I am concerned about the "Cristobalite Link" below, in that it seems to overlap "silica", "cristobalite", and other forms of quartz. See: <a href="http://www.quartzpage.de/gen_mod.html">http://www.quartzpage.de/gen_mod.html</a> showing how various forms of quartz exist at various temperatures.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Note that "cristobalite" is one specific crystalline phase of quartz.</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Secondly, what is important is the "respirable" dust that is actually respired. </span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>It is well known that respiring "silica dust" can cause "Silicosis". It is well known that "Small Particulate Matter emissions" from virtually any poor stove can cause serious health problems. Hence, the effort to design "stove systems" that minimize "Small Particulate Matter Emissions" into the living space, where they can potentially be respired.</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Rice Hull Ash, even at 90% silica in the ash pit, is not a problem, in that it is in the ash pit, where it is not respired. On the other hand, an "apparently superior fuel" that only had say 25% silica content in the ash pit would be vastly more hazardous, if it vented 10 or 100 times as much ash into the living space, in respirable form.</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>This is where competent and meaningful stove design and testing comes into play. </span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>As has been said many times, "It is not so much the fuel, but the stove system design, that is good or bad."</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Best wishes,</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Kevin</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div></div></body></html>