KILN INSTALLATION

INSTALLING YOUR KILN

DATED INFORMATION The information in these installation instructions is believed to be correct to the best of our knowledge at the time of publication (August 4, 2022).

SAFETY APPROVALS Local fire and safety codes supersede information provided in these installation instructions, or in our caution instructions.

UL STANDARDS Many but not all kiln components are listed to UL 499 Standards for the US and Canada by MET a Nationally Recognized Testing Laboratory (NRTL).

NATIONAL ELECTRICAL CODE Be sure your electrician follows the National Electric Code and any other local requirements when hooking up the kiln. One of the requirements of this code that bears particular mentioning is the fact that you must fuse your kiln appliance for 125% of its rated maximum amperage draw. This explains why you see fusing requirements in our electrical specifications that are in excess of the amperage draw of the kiln. The fuse for the kiln is either a circuit breaker or a fused disconnect switch.

NATIONAL FIRE PROTECTION ASSOCIATION To the best of our knowledge, the NFPA has nothing specific about the installation of kilns. The NFPA 86 goes into considerable detail about industrial furnaces and ovens but generally with respect to internal processes and gas-fired equipment. There is one section in the NFPA 86 (Section 2-1.5 concerning Floors and Clearances) that might be construed as applicable to kilns. It requires that temperatures at combustible ceilings and floors be kept below 160°F (71°C). In general, the NFPA recommends installing furnaces on noncombustible surfaces and has specific requirements if this is not possible. You can order a copy of this by going to their website at www.nfpa.org or by calling 617-984-7249.

CLEARANCES & SURFACES CLEARANCES IN KILN ROOM Studio L, Inc. strongly recommends a ≥48" clearance to all walls. Make certain the floor is not flammable. The Uniform Mechanical Code 2000 Edition states that "the sides and tops of kilns shall be located a minimum of eighteen (18) inches (457 mm) from any non-combustible wall surface and three (3) feet (914 mm) from any combustible wall surface." The National Fire Protection Agency states that temperatures at combustible ceilings and floors be kept below 160 Deg F (71 Deg C) near industrial furnaces (which are like kilns). Note that, when Studio L, Inc. tested kilns, temperatures were measured 12" from the walls of the kiln and found to be safe from a flammability standpoint. However, locating a kiln just 12" from a wall may violate the Uniform Mechanical Code and possibly local fire codes, so do this at your own risk.

WALL MATERIALS Check with local building codes for recommended noncombustible wall materials for walls that are adjacent to the kiln. Cement board, cinder blocks, and masonry tile are possible choices.

FLOORS The Uniform Mechanical Code 2000 Edition states that "kilns shall be installed on noncombustible flooring consisting of at least two (2) inches (51 mm) of solid masonry or concrete extending at least twelve (12) inches (305 mm) beyond the base or supporting members of the kiln." Recommended floor surfaces are cement, ceramic tile, stone, slate, cinder blocks or brick. Do not install on a wood floor or on carpet. Vinyl flooring may be combustible.

BE VERY CAREFUL ABOUT IMPLEMENTING THESE SUGGESTIONS Remember that the kiln is putting out heat over a long period of time and that this could very well start a fire under certain conditions. Also, if an overfiring occurs, materials like glass and glazes can be super-heated and electrically conductive, and they can melt right through the kiln floor. If there is a combustible floor, this could cause a fire. Also, keep in mind the continued heat of the kiln can dry out combustible surfaces over time and reduce their flashpoint. The NFPA 86 (Section 2-1.5 concerning Floors and Clearances) that might be construed as applicable to kilns requires that temperatures at combustible ceilings and floors be kept below 160°F (71°C). In general, the NFPA recommends installing kilns on noncombustible surfaces and has specific requirements if this is not possible.

KILN BASE Studio L kiln bases are raised 25” above the floor to allow for proper air circulation under the kiln. It is CRITICAL to have air circulation under the kiln. This prevents heat from being directly conducted to the floor surface. If the floor (or subfloor) is combustible, a fire could result. Do not store materials under the kiln as it would result in fire danger.

OTHER CLEARANCES Make sure there is adequate clearance in the room for opening the kiln lid, and for periodic maintenance such as opening the element connection boxes.

KILN ROOM ENVIRONMENT - KEEP KILN DRY & IN A PROTECTED SPACE The kiln must be kept dry so it must be kept in an enclosed room away from inclement weather. The electrical circuits must not get wet. If for some reason they do get wet, they must be thoroughly dried before operating the kiln. Kilns can corrode rapidly if kept in rooms that have no climate control. The constant heating and cooling in an unheated shed, for instance, can cause dew to form on the cold metal and this can cause corrosion. Also, exposure to salt air will accelerate corrosion dramatically.

AMBIENT TEMPERATURE The kiln should operate in an environment that is between 0°F and 105°F. Some people keep their kilns in unheated garages or sheds. This is OK as long as the room is dry.

THE SURFACE IS HOT AND CAN CAUSE BURNS Kiln surface can be extremely hot: up to 150°F. Display a sign near the kiln that warns everyone of how hot the kiln is.

FIRE EXTINGUISHER We recommend that an adequate fire extinguisher be kept near the kiln and checked on a regular basis. You may want to check with your local fire authorities to see if there are any specific requirements such as sprinkler systems, automatic foam extinguishers, etc. Use a fire extinguisher that is rated for electrical fires. We recommend an ABC fire extinguisher.

FIRE SPRINKLERS If you have a sprinkler system, be careful to check the temperature rating and location of the heads so that you do not inadvertently cause them to actuate under normal firing conditions. Position the sprinkler heads in the ceiling away from the kiln(s). The rising heat from the kiln, under normal operating conditions, could set off the sprinklers which will cause water damage. Use the highest temperature rating on your sprinkler heads that is allowed by code. Or consider using a higher one that is set off by smoke. Be sure to monitor the temperature while the kiln is at its highest firing temperature and conditions are at their worst (for instance when the door to the kiln room is closed or the ventilation fan is turned off). Serious damage to the kiln and your premises can take place if the sprinkler system goes off when the kiln is at a high temperature, especially if no one is in the building when it happens.

KILN ADJUSTMENTS LEVELING THE KILN Level the kiln while you are installing it. Use adjustable pads under the legs to accomplish the leveling (never wood or other combustible materials).

THERMOCOUPLES Thermocouples are hard-wired into the kiln and must never be removed or disconnected. They protrude into the kiln itself because, if the measuring tip of the thermocouple is damaged, the thermocouple will measure a lower temperature than the actual temperature in the kiln or no temperature at all. This could cause an overfire of the kiln.

NOTE Replace thermocouples once they are no longer reasonably accurate. (Note: Type K thermocouples last about the same as kiln elements, so it is recommended to change thermocouples when you change elements.) If you have taken the kiln apart, carefully observe the thermocouple polarity and zone placement.

VENTILATION REQUIREMENTS Kilns are intended for thermal forming and thermal fusing glass. Using the kilns for this purpose will not generate harmful fumes, and therefore does not require special ventilation. Ventilation, however, may be needed for excess heat build-up in the room. Kilns are NOT recommended for firing ceramics. Ceramics will produce fumes and can include carbon monoxide, formaldehyde, sulfur dioxide, heavy metal vapors, and fluorides (all of which can be very toxic).

CARBON MONOXIDE MONITORING We recommend the use of a carbon monoxide monitor in your kiln room.

AIR CONDITIONING ISSUES Kilns put out a lot of ambient heat. You may need to size HVAC units to handle this.

ELECTRICAL REQUIREMENTS Two (2) 50-amp 480V 3-phase w/ground. Prior to kiln arrival, the customer needs to have a certified electrician install two 50-amp 480V 3-phase w/ground circuits to a junction box where the kiln is going to be installed. Each junction box should have two (2) ROYAL® SOOW CORD 6 gauge, 4 conductor (6/4) 600 Volt 90°C Flexible cords long enough to easily reach the kiln control panel. Each 6/4 SOOW cord must have a HUBBELL Twist-Lock® device 50A, 250V DC, 600V AC, 3 Pole, 4 Wire Grounding Insulgrip® male connector on the end to plug into the kiln control panel.

CHECK WITH A QUALIFIED ELECTRICIAN The ground wire is not used as a neutral (i.e. no electricity normally flows through the ground). BE SURE TO GROUND THE KILN PROPERLY USING THE GROUND WIRE. AN UNGROUNDED KILN IS A DANGEROUS KILN. Also, it is important for the control operation to have a good earth ground as well (to get rid of electrical noise). Ensure that your power lines are heavy enough to carry the required electrical load. If this is being used in an industrial or institutional setting be sure to follow lockout/tag-out requirements and procedures.

USE A FUSED DISCONNECT We recommend having a separate fused disconnect box with a lockout provision mounted near the kiln, even if you also have a separate circuit breaker for your kiln. This way you can easily turn off power to the kiln and prevent unauthorized people from turning it on. We recommend this even for kilns with plugs because it makes it so much easier to disconnect all power to the kiln when not using it. Note that if you unplug a kiln frequently the spring tension in the outlet can weaken over time. A fused disconnect switch allows you to positively turn off power to the kiln without unplugging it. Locate kiln within 50 feet of the breaker. Try to locate the kiln within 50 feet of your breaker box. For longer runs, you will probably have to increase the size of the hook-up wire we recommend in our literature. In any case, be sure to have a licensed electrician who knows the National Electrical Code hook up the kiln and size the hookup wire.

FUSING YOUR CIRCUIT Be sure your electrician follows the National Electric Code and any other local requirements when hooking up the kiln. CHECK WITH A QUALIFIED ELECTRICIAN.

PROPER GROUNDING Make sure your electrician properly grounds the kiln and then tests for proper grounding after the installation. All electrical appliances should be properly grounded. This is especially important with the high voltage used on kilns. The higher the voltage the more easily it could flow through your body. In addition, because of the heat generated in a kiln, wires are subject to potential deterioration over time, and expansion and contraction can move insulators and cause short circuits. BE SURE TO REPLACE ANY DETERIORATED WIRES!

USE THE PROPER WIRE GAUGE Hook-up wire sizes are provided for many of our kilns in the electrical specifications. However, this can vary depending on ambient temperature conditions and the length of the wire run. Running power for your kiln over a long distance will result in a drop in voltage. USE COPPER WIRE FOR HOOK UP. Don't use aluminum wire. It is cheaper to use aluminum wire and you may be tempted to do so. Many electricians will tell you that, with the new types of connectors, it is okay. However, it is of particular importance with kilns not to use aluminum wire for the hookups. The specific reason particular to kilns is that the wire tends to get hotter near the kiln than it might be going into some other types of appliance. Also, being a resistive load, there is constant heat being generated by the conductors. When aluminum wire gets hot it accelerates oxidation. Aluminum oxide is a resistor; copper oxide is not as much. If the connection at the terminal board gets oxidized, it will really heat up - to the point where it could cause a fire. Braided copper wire is preferred.