An 11" by 17" Kiln Cautions Poster is available for download. This has an abbreviated list of essential kiln cautions you can display in your studio. Be sure to read through the entire list of cautions here or in your instruction manual. 

Click here to download the Cautions Poster.

Kiln Safety and User Responsibility

• L&L Kiln Mfg. Inc. provides safety guidelines to help users operate their kilns safely and effectively. Many of these precautions apply to all kilns and ceramic processes.
• By using or downloading content from this website, users acknowledge that improperly installed, maintained, or operated kilns and manufacturing systems can pose serious risks to worker safety, the environment, and product quality.
• Kilns operate at high temperatures and high voltage/amperage. If not installed, maintained, or used correctly, they can cause severe personal injury or property damage.
• Commercial kilns come with built-in safety and performance features. Tampering with or altering these features—whether by the user, employees, agents, or others—shifts all risk and responsibility solely to the user.
• Users must ensure that only properly trained personnel, with demonstrated competence and common sense, operate the kilns.
• The user is responsible for understanding and following all safety notices, installation, operation, and maintenance instructions provided by L&L Kiln Mfg. Inc.

1. In automatic kilns, thermocouples must extend at least 1" (2.5 cm) into the kiln from the interior surface.
2. The measuring tip must be exposed inside the kiln—if buried in insulation, it will read a lower temperature than the actual kiln temperature, potentially causing overfiring.
3. Replace thermocouples when they are no longer providing accurate readings or are corroded.

1. Always use the supplied stand—never operate the kiln without it.
2. Heat can transfer through solid materials, drying out combustibles and lowering their ignition point, increasing the risk of fire.
3. Adequate airflow under the kiln is essential—never place a kiln directly on the floor.
4. L&L kiln stands typically raise the kiln floor 8" (20 cm), except for the Plug-n-Fire model, which is 5" (13 cm).
5. See this link about installing kiln on a wood floor.

Clearances

• Maintain 18" of clearance from noncombustible walls/materials and 36" from combustible walls/materials.
• Ensure ample room to open the kiln lid and access control panels, typically 18" to 24" around the kiln.
• Keep surface temperatures near the kiln under 125°F (52°C) to reduce fire risk.
• Remember, even when you follow clearance and ventilation recommendations, the kiln gives off heat. Avoid locating it near things that can be affected by elevated temperatures. An example would be an electrical fuse panel, which you do not want to overheat.
• Be careful about enclosed spaces: In general, installing a kiln in a small confined space (such as a closet) is not a good idea.

Wall & Floor Materials

• Walls: Choose noncombustible materials like cement board, cinder blocks, or masonry. Consider installing a heat-resistant barrier if closer clearances are necessary.
• Floors: Install kilns on noncombustible surfaces (cement, ceramic tile, stone, slate, masonry) with at least 2" thickness, extending 12" beyond the kiln footprint.
• Never place kilns on wood flooring, carpet, or potentially flammable materials. Even cement floors benefit from the kiln stand for proper air circulation.

1. Rout Power Cord (or electrical connection wires) away from kiln in such a way that it can not touch the hot case of the kiln.
2. Secure it so it can not move.
3. If cord touches the hot case it could melt and cause a short circuit and/or fire.

1. Never use an extension cord with your kiln.
2. Voltage drop risk: Extension cords reduce voltage over distance, which can cause the kiln to underperform or overheat wiring.
3. Overheating and fire hazard: Standard extension cords are not rated for the high amperage kilns require. Overloaded cords can melt insulation, damage connections, and start fires.
4. Direct connection is safer: Position the outlet close enough for the kiln’s supplied power cord to plug in directly.
5. Hardwiring required for high-power kilns: Kilns over 48 amps and some three-phase models do not have power cords and must be wired directly to the power supply.
6. Warranty and safety compliance: You can directly wire any kiln without voiding the warranty or affecting the UL499 rating. Use 105°C-rated wire for safe installation.

1. The kiln must be kept dry.
2. Keeping it in an enclosed room away from inclement weather is best. The installation instructions provide specific details.
3. Note that our warranty does not cover damage from corrosion and electrical damage caused by inclement weather.
4. Water in contact with a kiln can cause an electrocution hazard.
5. If you keep a kiln outside (even in an arid environment) and cover it with a tarp to protect it from rain, you could still cause corrosion from the dew that forms on the cold metal surface of the kiln in the morning.

1. Check temperatures around kiln when it is operating at high levels to ensure it is not creating an unsafe condition.
2. Surfaces that remain below 71°C (160°F) are generally considered safe, meaning they will not spontaneously catch fire. However, prolonged exposure to heat can dry out materials, lowering their ignition point over time.

For safety:

• Keep surrounding surfaces below 160°F (71°C) during operation.
• Use heat-resistant barriers (such as cement board) if surfaces may exceed this temperature.
• Maintain adequate clearances and ventilation to minimize heat buildup.

1. Keep an adequate fire extinguisher near the kiln and check it regularly.
2. Consult local fire authorities for any specific requirements, such as sprinkler systems or automatic foam extinguishers.
3. Use a fire extinguisher rated for electrical fires—an ABC-rated extinguisher is recommended.

1.  The kiln should operate in an environment that is between -18°C (0°F ) and 38°C (100°F).
2. Note that the control, if set up for degrees centigrade, may give you an error code if room temperature drops below 0°C (32°F). The Genesis, DynaTrol, and most other controls do not handle negative numbers.

1. Do not put sealed containers or combustible materials such as solvents, paper, rags, in or near kiln.
2. The kiln elements, when hot, could act as ignitor of flammable fumes. 
3. An explosion or fire could result.

1. Kilns generate harmful fumes when firing ceramics.
2. Fumes include carbon monoxide, sulfur oxides, hydrogen fluoride and metal vapors (all of which can be very toxic).
3. Install kiln in well-ventilated area.
4. Never operate in an enclosed space such as a closet unless you have good ventilation.
5. Aside from issues of ventilating the fumes from the firing, the heat build up in an enclosed room could present a significant fire hazard. See the INSTALLATION cautions.
6. Severe corrosion can be caused by kiln fumes, salt air or other environmental conditions.
7. Good venting can minimize these problems.
8. Ventilation must be to the outside.
9. Be careful not to locate the outlet of the vent near an open window (so that it could get sucked back into the building).

Helpful Tips

• Ventilation Guidelines
• See this for how to calculate ventilation requirements.
• Where should I put my kiln?
• Corrosion and ventilation
• If you are using a hood type vent (like the Vent-a-Kiln) do you need a kiln vent (like the Vent-Sure) also?

1. When working around a hot kiln, be careful of the kinds of clothes you are wearing.
2. Some clothes could catch on fire if they touch the hot surface of a kiln.
3. Also avoid loose fitting clothes that could catch on the kiln.

1. Clay contains silica dust, which can be harmful (see silica caution), and some glazes contain heavy metals such as lead, cadmium, and copper.
2. While this caution is outside the scope of kiln safety, it is worth mentioning here.
3. Keep your room clean and your kiln clean.

1. Kiln surface can be extremely hot: up to 260°C (500°F).
2. You can be severely burned if you touch the hot surface.
3. Display a sign near the kiln that specifically warns everyone of how hot the kiln is.

1. Keep children, animals, and unqualified adults away from the kiln.
2. Kilns pose risks from heat, electrical hazards, fumes, and fire.
3. Ensure proper ventilation and fire safety measures.
4. In schools or shared spaces, place kilns in restricted areas where children cannot access them unsupervised.

1. Long-term exposure to silica dust can cause lung damage.
2. Check your supplier's Material Safety Data Sheets (MSDS) for safety information.
3. Use caution when handling dry powders and cleaning kiln shelves to minimize dust exposure.
4. Wear a NIOSH-approved particulate respirator (e.g., #TC-21C-132) and ensure proper ventilation.
5. Respirators are available from safety supply stores.

1. We recommend not using silica sand in the kiln (often used as a work support medium).
2. The silica can attack and reduce the life of the elements and thermocouples. (Details: At high temperatures, silica can combine with aluminum oxide to form compounds like aluminosilicates, which may attach to the elements' surface. This can degrade the protective oxide layer, increasing oxidation and corrosion, and reducing element life. Additionally, silica can potentially melt and adhere to the elements at high enough temperatures, further exacerbating the wear.)
3. We recommend alumina oxide or zirconia oxide sand.
4. If you use silica sand, vacuum the kiln after each load.

1. Ensure the kiln floor and the tops of shelves are coated with kiln wash to protect against melting glaze and ceramics.
2. Do not coat the undersides or sides of shelves.
3. Never apply kiln wash to brick sides or element holders, as this can damage the elements.
4. If using a kiln sitter, apply kiln wash to the cone supports, but not the sensing rod, for accurate cone action.
5. Remove old kiln wash and reapply before each firing or when it starts to chip.
6. Kiln wash is not supplied by L&L—purchase from a local ceramic dealer.

1. Never load moist greenware or pots into the kiln.
2. Trapped water can turn to steam and cause explosions, damaging the kiln interior.
3. To remove moisture, Use a dry-out segment in your bisque firing program at 66°C (150°F).
4. Even if the piece looks dry, it may still contain water. If it feels cool against your wrist, it likely has too much moisture to fire safely.

1. Avoid firing plastics, organic materials, bakeable modeling clay, mothballs, and other non-ceramic substances in the kiln. Many materials release toxic fumes or combust uncontrollably when heated.
2. Rocks, marbles, and cement can explode at high temperatures.
3. Only fire ceramics, glass, and metal from a reputable source—constantly research how a material reacts to heat. The user is solely responsible for safe firing.
4. Kilns are not designed for hazardous materials.
5. Introducing propane, wood, charcoal, or other materials to create a reduction atmosphere can be dangerous. Under certain conditions, the air-to-fuel ratio can cause an explosion, leading to serious injury or death.
6. A reducing atmosphere can damage kiln elements, causing premature failure by breaking down their protective oxide coating.
7. Carbon-based materials decompose at high temperatures, releasing poisonous carbon monoxide and flammable hydrogen.
8. Flammable gases auto-ignite above 1400°F, creating additional fire and explosion risks.

1. Tempered glass can explode when fired.

1. When you heat wax (in wax resist and lost wax processes) it will volatilize and potentially condense in the cooler ventilation ducts.
2. this can cause a fire hazard over time because the wax is flammable.
3. Depending on how the vent motor is mounted, the wax can also gum up the vent motor.
4. If you use these processes, it is entirely up to you to engineer and monitor the safety of the installation.
5. The use of wax will void the warranty of the vent system.

1. Use dark glasses (shade 1.7 to 3.0) when looking inside the kiln through peepholes or the door to protect your eyes from infrared radiation and potential explosions. Regular sunglasses do not provide adequate protection.
2. Wear heat-resistant gloves when handling peephole plugs or the kiln door, as they can cause burns.
3. Never open the kiln lid while it is on, except for controlled troubleshooting tests. Opening the lid while powered can cause electrocution, and cracks from propping it open are not covered by the warranty.
4. Always wear heat-resistant gloves when opening a hot lid, and never open the lid if the kiln temperature exceeds 121°C (250°F).

1. Keep lid closed when not operating the kiln.
2. Otherwise, the lid's weight over time may force the hinge and stainless wrap to move down.
3. This will affect how the lid closes and may cause the lid to crack.
4. It will also keep the kiln cleaner by keeping dust out.
5. If the kiln gets turned on accidentally, an open kiln could present a fire hazard.

1. Do not use the lid as a storage shelf.
2. The lid could crack.
3. Also - this practice could lead to a fire if you accidentally leave combustible materials on the lid.

1. Turn off the power when loading or servicing the kiln.
2. If the kiln is on, accidental contact with the elements can cause electrocution.
3. In institutional or industrial settings, use a fused disconnect switch with a lockout device to prevent someone from turning on the kiln while another person is working on it.

1. You may burn yourself.
2. You may harm your work.

1. Stilt marks and other sharp protrusions can cut you.
2. Remember that that glaze is like glass.
3. Wear safety glasses while grinding or knocking of stilt marks.
4. Check the shelves for broken bits of glaze which may have attached to the shelves. These can be like shards of glass that can cause a serious cut.

1. We recommend attending the kiln while firing.
2. NO AUTOMATIC SAFETY DEVICE IS FOOLPROOF! BE ESPECIALLY CAREFUL ABOUT ATTENDING THE KILN WHILE IT IS SUPPOSED TO SHUT OFF. (The Delay feature in automatic kilns gives you control over this).
3. The controller is used to control temperature; it is not a safety device.
4. If you have a manual kiln with a Kiln Sitter PLEASE BE EXTRA CAREFUL! Kiln sitters can be very unreliable because of the moving parts, dirt or clay that can get into the tube, the way cones are placed on the tube, corrosion, etc. DO NOT FIRE THIS KILN UNATTENDED WHEN THE KILN IS SUPPOSED TO TURN OFF AND LEARN HOW TO USE THE TIMER BACK UP. Neither L&L Kiln Mfg., Inc. nor Edward Orton Jr. Ceramic Foundation warranty the kiln or kiln sitter against damage caused by overfiring. ALMOST ALL OVERFIRED KILNS WE SEE ARE FROM A MALFUNCTION OF A KILN SITTER. We highly recommend firing all manual kilns with witness cones that you can see through the peephole and/or a pyrometer so you have some idea of what is happening inside the kiln.

1. Become familiar with either the control (if you have an automatic kiln) or the Kiln Sitter (if you have a manual control or have that as your backup control).
2. Do this before operating the kiln.

1. Check element holders and walls for glaze, clay chips or anything that could melt at a high temperature.
2. If melted clay or glaze comes in contact with an element, a rapid failure could result. The molten material traps the heat radiating from the element and subsequently raises the surface temperature of the wire. The temperature will quickly pass the maximum recommended temperature for the wire and burn it through it.
3. To clean holders, a good shop vacuum will handle dust and loose crumbs. A very gentle chisel or grinder may help with glaze contamination on element holders, but remember that the elements themselves are quite brittle when they are cool.
4. Replace the contaminated channel if you cannot clean it.
5. Remove any glaze that has splattered on the firebrick or shelves. (USE SAFETY GLASSES WHEN DOING THIS BECAUSE GLAZE CAN BE LIKE BROKEN GLASS). Vacuum afterward. Note about vacuuming: it is possible to build up a strong static electricity charge when you are vacuuming. If this somehow manages to discharge into the control it can ruin the electronic circuit. Make sure vacuum is grounded and periodically touch some grounded metal surface away from the kiln to discharge the energy.

1. Shut off the kiln when servicing it unless you are doing a live test that specifically calls for power. If you are in an institutional or commercial setting, use a lock out/tag out procedure. Unplug if the kiln includes a plug; if not, turn off at the closest circuit breaker or fused disconnect.
2. You do not need the kiln powered when testing ohms for an element circuit.
3. The elements carry high voltage and can electrocute you. Many of the tests described in the troubleshooting manual are performed under power. They should be done ONLY by someone familiar with electrical safety, such as an electrician or trained maintenance person.
4. You are safe as long as the kiln is unplugged or turned off at the fused disconnect switch or circuit breaker (and checked with a reliable meter to be sure).

READ THE FULL CAUTION ABOUT ELECTRICAL SAFETY

1. Check wires for deterioration or oxidation.
2. Replace any that seem brittle or where the wire insulation has deteriorated or fallen off.
3. Check terminals for oxidation (discoloration).
4. If you are near salt air or notice corrosion on the stainless exterior of the kiln for whatever reason (like certain fumes generated by your work), do this far more frequently.
5. Check the power connection terminals in the kiln and control box for tightness. Be sure to do this with the kiln's power disconnected (unplugged). If these terminal connections get loose, heat can be generated (because the electrical resistance increases), which can cause a fire.
6. Check thermocouple connections for corrosion, tightness, and oxidation. A bad thermocouple connection can affect the accuracy of the temperature reading, which could cause overfiring.

1. Occasionally check temperatures of the main power cord at the main receptacle and the main kiln breaker while the kiln is at its hottest.
2. If these are hotter than usual, it could be a sign of a loose or corroded connection, or possibly the wire gauge used in the power hook-up is the wrong size for the amount of current being drawn by the kiln.
3. Immediately diagnose and fix this because it could cause a fire.
4. Also check temperature of any other cords on the kilns (such as element jumper cords).

1. When replacing infinite zone switches (and other electrical components), replace the electrical connectors.
2. At the very least check for discoloration (an indication of oxidation).
3. Electrical connectors will typically oxidize over time where there is heat, which can cause further overheating of the part at the connection point. This can, in turn, lead to early failure of the part, wire, and connector.
4. Ensure the new connectors are firmly crimped onto the wire.

1. Non-L&L elements can present a potential hazard to the kiln or cause a fire (by drawing too much amperage).
2. The wrong type of fuse, relay, switch or other component can cause a fire or other hazardous condition.
3. An improperly rated cord can cause a fire. 

1. We do not recommend any coatings for the elements.
2. The use of ceramic coatings will void the warranty on the elements and potentially the firebrick or element holders if they contaminate them.
3. We have not adequately tested these coatings, so we can only say, at this time, that any trouble that results from the use of ITC and other coatings must be at the user's risk.
4. We do use a proprietary coating on all our firebrick that improves firebrick life and reduces dusting.

1. All customer modification is made solely at the customer's risk.
2. Modifications will void the warranty.
3. L&L takes no responsibility for hazardous conditions created by unauthorized modifications.
4. Any authorization for an engineering change must be in writing from the factory.