We are often asked where to put a kiln and ventilation questions. Below is a helpful guide so you can fire safely and what you might have to prepare for.

 

Fumes and gases from kilns can be hazardous to health when… you fire a lot, with a high concentration of wares, use materials that include toxic ingredients, fire in environments that have limited airflow, or work near the kiln when firing. All this creates a high risk to your health. You can lessen the risk if you do the opposite... Fire occasionally, with small amounts, using safer materials, fire at times when you are not in the same environment and doing so in a well-ventilated room.

 

The general advice on ventilation is to consider good airflow. Movement of air is what is required. You need cold air to come into the room from a low point and the warm humid air to exit at a high point. This does not usually present a problem if you intend to site the kiln in a garage or outbuilding where drafts are commonplace, but if your room is modern and airtight then you will need to open a window at the very least, or install airbricks and with very poor air circulation; powered extraction. The popular top loader model has as part of the accessories a metal exhaust flue adaptor. Upon this you can purchase flexible ducting (which we sell). You could encourage warm exhaust air through this ducting, If the tube is straight and as short (<3m) all the better. If going through a roof, don't forget a cowling to protect against the rain. When installing ventilation grilles or holes think about the placement. A place for cool air to enter could be the shaded area of the building. 

 

We have talked to people wanting to put kilns in unused rooms within a house and basements where air flow might be a problem. This is not an ideal place to put a kiln but if you have no other choice, I would strongly advise creating movement of air by means of powered extraction.  

 

Consider insulation within the room. Modern kilns have sensors that can tell when the environment is heating up and can switch off if a room too hot, so insulate within from the heat outside. Another benefit is for the protection from condensation, for instance a cold room/building during winter with an electrical appliance that has in part cold metal surfaces which could attract moisture and you may develop electrical issues as a result.

 

With a new or modern kiln, you can position a kiln at least 30 cm from a wall. If you have limited space, then all the kilns we supply can have additional castors which will allow the pulling out into position when firing and returning safe when cool. In small environments or with low ceilings avoid the practice of lifting kiln lids to advance cooling as a lot of heat would escape moving upward and potentially causing a fire. Do not lift the lid until the temperature inside the kiln is the same as the outside. The heat from the outside of a modern kiln is minimal, some worry that floors will become hot. We have found this not to be the case, but we do advise protection of surfaces, say a flooring which may become discoloured after a kiln is in one position for many years.

If you are productive or a professional potter, you should take the time to read the references listed below. Remember as the risks start to increase, you will need to plan for ventilation and think about the placement before you commit yourself to a new kiln.

A good book on kilns, The Electric Kiln by Harry Fraser A&C Black ISBN 0-7136-3745-5

There is a HSE document also with good advice for schools and institutions… with other links at the bottom for gas kilns http://www.hse.gov.uk/non-metallic-minerals/kilns-in-schools.htm

For the technically minded there was a study done on the emissions from the kiln which would explain the differences between bisque and glaze firings with vented and non-vented kilns, research on-line, Parker C Reist, Chapel Hill, North Carolina USA - ceramics

Finally, if you are in any doubt as to the safety and of the use of your kiln, please do call us here at Hot Clay on 01934863040 (opt 3) to speak to our Technical Coordinator, or contact us via email info@hot-clay.co.uk