Oops..7 inches not enough?

Ha! I thought i was making an 8-inch system when in fact the feed and the heat riser measure out to be around 7.15 inches x 7.15 inches.

Ive already built the combustion unit and want to know if 8 inch pipes would be too big? I plan to run 9 meters of pipe before exiting the house.

During my outdoor trials the top of the barrel got hot enough to cook my lunch (twice) so with the added insulation, the morter and the slightly shorter burn tunnel, my inclination is that there will be more than enough heat generated to provide for 9+ meters of bench piping. Or no?

Karl : You are O.K., By now you should already be an expert on the Constant Cross Sectional Area Of your Rocket Mass Heater R.M.H., and how to figure it !

To figure out the Cross Sectional area of a square we Multiply 7.+'' X 7.+'' = 50''-ish, Cross SectionalArea of your Exhaust pipes pi X (r)2 or 3.14 X (4x4) =
50''-ish , if your burn tunnel carries what is supposed to be Constant Cross Sectional Area you are good to go !

For everybody else let me say this one more time ! Know thy Constant Cross Sectional Area, and keep it Whole-y Big Al ! C. - C.S.A., keep it Whole-y !!!

Ask a question of Ernie or Erika, be enter'd into a drawing for Ericas new Book ! Big AL