UL's Approach to Safety Testing a Halogen Light Oven
Potential risks were identified as: eye damage from direct exposure to the light; risk of burns from exposure and/or contact with the lamps; exposure to ultraviolet radiation (UV) emitted from the lamps; and injury resulting from contact with the lamps (especially if broken).
The following is an overview of the safety testing halogen-light ovens are subjected to by Underwriters Laboratories (UL). The overall test program may vary based on the specific construction of the halogen-light oven.
Input. This test is conducted to determine if the unit is properly rated and to determine which cooking mode draws the most current. The cooking mode is then used for the temperature test.
Temperature. This test is conducted to verify that the halogen-light oven does not reach a temperature at any point high enough to cause a risk of fire, damage to any material used or exceed temperatures specified by the standard during normal and abnormal operation.
Dielectric Voltage Withstand. This test is conducted to verify the halogen-light over is properly insulated. Also, low- voltage and line-voltage components and grounded parts are properly spaced from one another.
Grounding Continuity. This test is conducted to verify that a dead metal part such as the oven lining is adequately connected to the grounding means of the oven so that the user doesn't get shocked when they contact the dead metal part.
Oven Door Integrity. A 50-lb. load was applied on the top center of a fully
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open oven door. After five minutes, the oven is inspected to determine if there is any breakage or damage to any part of the door or appliance.
Cleaning Test. The cleaning test is conducted to ensure that the user does not receive an electric shock when cleaning the control panel. The control panel including the keypad are sprayed with a general-purpose glass cleaner, left on for 10 sec. and then wiped with an absorbent paper towel. The test is repeated with a liquid all-purpose cleaner.
Impact. The glass control panel and glass lenses that protect the lamps are subjected to an impact test of 5 ft-lbf (6.8J) to verify that the glass will not break when bumped with cooking
Strength of Mounting. This test is conducted on wall-mounted units and cabinet mounted units and is intended to verify that the oven does not break free from its mounting means. The oven is installed per the manufacturer's installation instructions. A 50-lb. weight is placed inside the oven centered on the oven liner. Another 50-lb. weight is applied to the outer edge of the oven door. The weights are applied for five minutes.
Interlock System Endurance Testing. The door and door interlock system, in conjunction with the halogen-light oven is subjected to 100,000 cycles of operation (opening and closing the door). During and after the completion of testing there shall be no electrical or mechanical malfunction, loosening or shifting of adjustments or parts that could result in the likelihood of fire, electric shock, injury to persons, or excessive ultraviolet (UV) radiation.
Thermal Shock. To verify the glass protecting the lamps will not break or shatter if splashed by cold food products, the oven is operated for ½ hour at its maximum heat setting. 500 ml of water at room temperature is then poured over the cooking surface.
Ultraviolet Radiation. This test is conducted to prevent eye damage from the intense light when the oven is operated or opened. All removable parts, such as lenses and filters that are user serviceable removed if they would result in an increase in the amount of ultraviolet radiation exposure to the user. The emitted ultraviolet radiation is measured with the halogen-light oven energized and the controls adjusted to the level that resulted in the greatest amount of ultraviolet radiation emanating from the oven. Limits were derived from guidelines set forth by the American Conference of Governmental Industrial Hygienists (ACGIH).
Spill Test on Horizontal Surfaces.
This test is conducted on ovens that employ electrical components or internal wiring located beneath openings in the oven cavity. Typically the floor of the oven is glass and this test determines that the glass will not shatter when liquid is spilled on it. While the oven is operating, a solution of 500 ml of distilled water containing ¼ g of ordinary table salt was poured at random over the inside of the oven cavity. Immediately after the spillage, a dielectric-voltage test isconducted.
Fire Isolation Test. This test is conducted on an oven that is intended to be installed above a range or counter-mounted cooking unit. Since the amount of space between the cooking surface and the kitchen cabinets is reduced, it is verified that the oven doesn't contribute to a fire of the building structure. An iron skillet pan with a predetermined amount of oil is placed on a burner located beneath the oven.
Cavity Fire Containment. These tests are conducted to ensure that the oven has the ability to contain a fire within the cavity, the oven is subjected to the same tests conducted on microwave ovens using potatoes and popcorn. After the tests are completed, the leakage current and dielectric withstand tests are conducted to make sure someone doesn't get shocked when they investigate the problem.