Published Nov 8, 2021
ceramic studio safety precaution, but a proper kiln ventilation system benefits both the work inside the kiln and the people (and don’t forget studio pets!) around it. In addition, a good kiln exhaust system is good for your kiln!If you are looking to buy a kiln, you will need to consider a kiln exhaust system too. Typically we think of kiln vents as primarily a
In this post, an excerpt from the Ceramics Monthly archive, Dave Finkelnburg explains how a kiln exhaust system works and why all kilns should be vented. - Jennifer Poellot Harnetty, editor
PS. Learn more about the problems caused by not venting a kiln, and how to properly use and care for your kiln vent in the April 2017 issue of Ceramics Monthly!
Why Vent a Kiln?
Kiln vents are primarily used to protect the health of people around the kiln. An additional benefit is that a vented kiln produces cleaner firings, ultimately contributing to brighter glaze colors and fewer glaze faults. A kiln exhaust system can also be used to cool the kiln more rapidly, but in a controlled manner.
All kiln firings produce fumes by burning off organic material from either the clay body or glazes. The fumes produced in any firing are water, carbon, sulfur compounds, and potentially heavy metals if the firing temperature is hot enough and volatile metals are present. Carbon is mostly carbon dioxide, but also a little carbon monoxide. Other volatile carbon compounds can come off early in the firing. Most carbon compounds come from the organic materials in the clay body, but some carbon dioxide comes from decomposition of carbonates (whiting and dolomite) late in the firing. However, any gum or other organic material added to a glaze also contributes organics to the kiln atmosphere, as do oils used if one is firing overglazes. Sulfur compounds burn off from pyrite, a minor contaminant in clays. Without proper kiln venting, these vapors will leak into the kiln room and become a health hazard.
Sulfur fumes are particularly irritating, producing a burning sensation in the eyes, nose, and lungs. Organic burnout produces compounds that can be harmful for a variety of reasons. The most immediate hazard is the potential for carbon monoxide to be present in the kiln fumes.
How Does Kiln Venting, or Not, Affect the Fired Work?
**First published in 2017.