On Monday, 8 January 2018 00:56:08 UTC+1, sincl...@hotmail.com  wrote:   
   > On Tuesday, 3 February 1998 09:00:00 UTC+1, Peter Mott  wrote:   
   > > Steve Holzworth wrote:   
   > > >    
   > > > This is a branch of a discussion from rec.boats about cook stoves.   
   > > > There is a disagreement about the relative densities and energy   
   > > > content of assorted stove fuels, including butane, propane, and alcohol.   
   > > >    
   > > > I was under the impression that propane is heavier than air (which makes   
   > > > using it on a boat an exercise in caution). Butane, I'm not sure about.   
   > > > I was also under the impression that propane and butane burn with a   
   hotter   
   > > > flame than alcohol. Any chemists out there care to comment (references   
   > > > would be great)?   
   > > >    
   > > > I know that butane and propane are both hydrocarbon gasses, and I seem   
   > > > to remember hearing that butane is lighter than air and propane is   
   > > > heavier than air.   
   > >    
   > > I can't resist a question that I know the answer to...   
   > >    
   > > air = 80% N2 + 20% O2 = 28(0.8) + 32(0.2) = 28.8   
   > > propane = C3H8 = 44   
   > > butane = C4H10 = 58   
   > >    
   > > --> Both butane and propane are heavier than air.   
   > >    
   > > Energy content is a more complicated.  As a camper, I would be concerned   
   > > with then energy content as a function    
   > > of the weight of the thing I carry.  Propane can be liquified,    
   > > but the tank will be heavier because    
   > >    
   > > Peter Mott   
   >    
   > An interesting post Peter, but one question as a layman; Why should the   
   instructions of the co2 detector recommend fixing it onto the ceiling? If   
   butane is heavier than air, should it not be fixed to the wall? It could be of   
   course, badly translated    
   English from the Chinese manufacturer. Appreciate your advice. Rgds Sinclair   
      
   I've found the answer; Butane is heavier than air but Co2 is lighter and its   
   Co2 gas that we are detecting. Apparently, Co2 detectors should be fixed on a   
   wall, not the ceiling because heat that stows above will stop detection,   and   
   the detector should    
   be 15 feet away from the source of heat. Rgds   
      
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