There are a lot of tile and brick making operations along the Pan Am Highway not too far out of Managua and most seem, like this one, to be family operated. Everybody has a job...some mix the clay-ash-water that makes the tiles and bricks; another cuts or gathers the wood and stacks it close by for the firing; someone else loads the kiln; and on it goes. Here are three generations who operate this kiln (with a volcano and a woman visitor showing in the background).
After the clay, packed into molds, is partially dry the bricks or tiles are removed from the molds and placed on the ground to dry some more. When thoroughly dry - and the people who do this for a living are good judges of 'thoroughly dry' - they're packed into an underground kiln similar to an 'anagama' kiln which is a very old sort of wood fired kiln that originated in the far east...basically a cave or hole in the ground with a door at one end and a flue at the other end. A fire is built just inside the door and the heat from the fire is then pulled over and around the raw materials in the cave until they're fully 'cooked' or fired. How much can be fired depends on how big the cave is. Below is greenware awaiting firing - two different shapes of floor tile.
Once the kiln is loaded a wood fire is started that gets hot enough to burn the wood so fast that it needs to be fed around the clock...and it burns for days. Although there was no official temperature reading at the kiln I visited, the best guess from the resultant tiles and bricks, is about 2,500 degrees Fahrenheit.
The man who keeps the fire going at this operation is a senior and has, according to the rest of his family, built up some sort of tolerance to the heat over his decades of working with the fire and kiln. I couldn't get very close to the ramp leading down to the kiln's front door...hard to imagine how this guy managed to feed the fire. Much of the kiln is under roof and firewood is stacked nearby, including on the ramp leading down to the entrance.