Kiln Ventilation & Safety for Pottery Studios

Part of Open Your Studio, our guide series for opening a pottery studio in the UK.

A kiln is the most powerful thing in your building. It runs at well over 1,000°C for eight hours or more, often overnight, in a place full of members, students, and sometimes children. Most first-time studio owners don't worry about the wheels at all. It's the kiln that keeps them awake: where does it go, what comes out of it, and what happens if someone touches it?

Here's what we've learned from kitting out teaching rooms. Nearly everything that makes a kiln safe is decided before it arrives. Where it stands, what it stands on, how the air leaves the room and who's allowed to programme it are all choices you make on paper, and they're cheap to get right on paper. Retrofitting them is not. If you haven't sized the kiln yet, start with the Kiln Size Calculator, then check its power with the Studio Power Calculator. The size decides most of what follows.

Give the kiln its own room, or at least a cage

The single best decision you can make is to put the kiln in a separate, lockable room or a caged-off area. Kilns and students don't mix during firing. The outer case gets hot enough to burn, the firing runs for most of a day, and a curious hand on a lid catch is all it takes.

The rule we'd hold to is simple: never put the kiln in a room people sit in while it's firing. That rules out the corner of the class room, the back of a paint-your-own café and the office. If space is tight, a mesh cage with a locking gate around the kiln and its clearances is a reasonable second best. Either way, put a clear sign on the door when a firing is on, and keep the key with the people trained to use it.

Clearances, the floor and the room itself

Once you know where the kiln is going, check the space against this list. Each item has a reason behind it, and most of them are about heat going somewhere you didn't plan for.

Think about the person loading it, too. Deep top-loaders are hard on backs, and a front-loader needs space in front for the door to swing and for someone to kneel. Our comparison of top- vs front-loading kilns covers the trade-off.

Ventilation: kiln vent or room fan?

Every firing gives off something. Early on it's water vapour, then the smoky, acrid burn-off of organic matter and carbon in the clay. Clays and glaze materials can also release sulphur compounds and other fumes, depending on what's in them. Your glaze materials' safety data sheets will tell you what to expect. Carbon monoxide can be produced during burn-off too. None of this should end up in a room where people are breathing. It needs to go outside: not into a corridor, not into the loft, not into the room next door.

There are two main ways to get it out, and many studios use both:

• A kiln vent fits to the kiln itself and draws a small, steady flow of air through the chamber, ducting it outside. It deals with fumes at the source and can help the firing run more evenly.
• Room extraction is a wall or ceiling fan, sometimes with a canopy hood over the kiln, exhausting outside, plus a way for fresh air to get in. It clears fumes that escape the kiln and stops the room overheating, which also protects the controller.

Put the exhaust somewhere sensible: away from opening windows, doors and neighbours. Cutting a hole in a wall usually needs landlord consent, and fans need power, so mention them to your electrician (our electrical requirements guide has the questions to ask). A carbon monoxide alarm in the kiln room costs little and is worth fitting. Ask your insurer whether they expect one.

Fire safety and your insurer

If you run non-domestic premises in England or Wales, the Regulatory Reform (Fire Safety) Order 2005 makes you, as the "responsible person", carry out a fire risk assessment, and since October 2023 you have to record the whole assessment in writing. Scotland has similar duties under its own fire safety law. The kiln belongs right at the centre of that assessment, alongside your fire exits, extinguishers and how people get out. If you're not confident doing it yourself, a fire risk assessor can, and they'll also advise on the right extinguishers for an electrical kiln room.

Tell your insurer about the kiln before you fire it. That includes its size and location, and whether you plan to fire overnight or unattended, because some policies have conditions about that. Our guide to insurance for a pottery studio covers what to ask.

Who loads and programmes the kiln

Decide this before the kiln arrives: named, trained people load and programme it, and nobody else does. Members can put work on the "to be fired" shelf. They shouldn't be pressing buttons on the controller. Mixed-up programmes are how glaze ends up welded to kiln shelves and bisque gets fired to stoneware temperatures.

Train at least two people so the studio doesn't stop when one is on holiday. Training should cover loading (dry glaze feet, gaps between pieces, shelf and prop arrangement), setting and checking programmes, what the controller's error codes mean, and the pre-firing checks: nothing touching the kiln, vent on, room door shut. Keep a simple firing log with the date, the programme, who loaded it and who unloaded it, plus any notes on elements or faults. It costs nothing and turns "it's been firing a bit slow lately" into something you can act on. And keep spare elements and a thermocouple in the cupboard. A busy kiln will need them, and you don't want a two-week wait with a class's work on the shelf.

Unloading, kiln furniture and PPE

Most kiln injuries happen at the end of a firing, not during it. A few habits prevent nearly all of them:

• Wait until it's cool. Follow the manufacturer's guidance on when to open. Opening early risks burns and can crack the work and the shelves through thermal shock.
• Gloves. Wear heat-resistant gloves for anything still warm. Glaze drips and broken pieces can be razor sharp.
• Shelves are heavy. Lift them with two hands, close to the body, and store them on edge in a rack near waist height, not stacked flat on the floor.
• Spyholes. Wear shaded safety glasses if you look into the kiln at temperature.
• Kiln wash and grinding. Scraping or grinding glaze drips off shelves makes fine dust. Do it with a suitable respirator and eye protection, then wet-wipe the area. Never sweep it up. That dust contains silica, which is the real long-term health issue in any pottery. Our silica and COSHH guide covers it properly.

Kiln room checklist

• Separate, lockable room or caged area, with a "firing in progress" sign
• 30 cm+ clearance to walls, room to walk round, nothing stored against it
• Non-combustible floor, checked for a 300 kg+ load
• Kiln vent and/or extraction to outside, with fresh air in
• Dedicated electrical circuit and a local isolator
• Fire risk assessment updated, insurer told, CO alarm fitted
• Two trained people, a firing log, and spare elements and a thermocouple
• Gloves, shaded glasses, a respirator for shelf grinding, and a shelf rack

Setting up at home rather than opening to the public? Our home kiln buying guide is the better place to start.

Keep reading

• Choosing a Kiln for a Studio: size, loading style and how many kilns.
• Electrical & Power Requirements: circuits, three-phase and questions for your electrician.
• Health & Safety: Silica Dust & COSHH: dust control, risk assessments and safety data sheets.