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Layout of the Yellow card
Approval of engineering plastics |
UL approval is generally essential before equipment can be sold in the United States. Approval tests on equipment are lengthy and expensive. The operation can however be greatly simplified if UL-approved materials, i.e. appearing on the yellow cards, are used. Engineering plastics manufacturers are therefore having an increasing number of materials approved, to make things easier for users.
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| Approvals covers three aspects: |
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flame class, governed by the UL 94 standard, |
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temperature indices, governed by the UL 746 B standard, |
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basic properties, determined under the UL 746 A standard. |
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The results are given for each material, in each colour, and for a specific thickness, which is the actual thickness of the specimen tested. This means that comparisons between materials are valid only if the thickness is the same.
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