On August 25, 2005 Jerry Frisch and Jim Buckley built a standard/typical western 36" masonry fireplace and the next day on the 26th we tested it using the fuel crib Ben Myren had developed for a metal 36" "zero-clearance" fireplace.
Basically the fire went out before the first load had burned after a fairly nice kindling start. Ben thought it may have been due to the combustion air flow over the bottom of the typical door frame. Or it could have been because the masonry fireplace has more mass than the ZC and needs more kindling to get up to temperature.
In the next few days Ben tested the fireplace two more times, with the door frame removed, with a different grate and larger kindling and fuel loads, and each time the fire went out. See his Report linked below.
In all three tests the bed of coals was not sufficient to maintain combustion. It looks as if more kindling and a larger fuel load will be necessary to maintain a fire in a masonry fireplace.
Building the Fireplace
Testing the Fireplace
Buckley Rumford Fireplaces
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