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The flammability classification of materials is created by recognition of the ignition and burning resistance characteristics of materials
other than metal or ceramic.
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Class of material
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Period of flame or glow before extinguish
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Glowing particles or flaming drops release ignite surgical cotton
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UL 94V-0
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< 5s
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no
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UL 94V-1
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< 25s
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no
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UL 94V-2
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< 25s
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yes
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UL 94HB
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less than Maximum burning rate
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possible
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Note: flammability test was originated from UL, it was being integrated into IEC 950.
Requirement
There are different flammability requirements for different parts of power supplies:
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Component
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Flammability Class
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Enclosure
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94V-1 or better
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PCB
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94V-1 or better
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IC, transistor package, optocoupler package, capacitor or other small parts
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94HB or better
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Cord anchorage bushings
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94HB or better
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Wiring harness
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94V-2 or complies withVW-1 or FT-1 or better
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Note: metals, ceramic materials and glass are considered to comply without test.
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