For a long time, LED filament lamps have faced two main problems in obtaining UL certification in the United States: firstly, the lamps must go out after being broken; The second is that the glass shell cannot be broken into pieces, but can only be broken into powder to avoid harm to the human body.
The first issue can be addressed on the power supply, but many manufacturers have different solutions to the second issue, which cannot effectively guarantee the success rate of certification.
Below, from the perspective of UL certification, we have explained the issues and key points that need to be paid attention to when passing the certification for LED filament lamp glass lampshade.
To solve the problem of LED filament lamp glass lampshade falling and breaking, the current common solution for LED manufacturers is to add some glue, glass glue or silicone to the inside or outside of the glass shade, to pull the glass and increase its strength, so that the glass will not break when dropped, and there will be no danger when fingers come into contact.
But this solution will face the problem of adhesive not being certified. How can we solve the problem of authentication in this situation? One scenario is that UL will measure the thickness of the control party's materials, RTI, and actual samples.
If the coating (adhesive) has certification, it is necessary to control the manufacturer and enterprise number of the adhesive and write them in the report. If this coating is not certified, some random tests need to be conducted to identify the material composition. This type of test is relatively rare in China and usually needs to be sent to Taiwan for testing. Annual FUS testing is also required to verify that the material cost has not changed.
Another way is to obtain UL certification for broken LED filament lampshades, which means that there is an updated UL standard in the first half of the year. It is acceptable for the glass lampshade of LED filament lamps to break after falling, but there are clear requirements and regulations for the area and size of glass breakage.
Firstly, three samples should be provided for drop testing, and then it is specified that the area of the lamp cover glass that falls after the drop test is broken should be greater than 75% of the area in the box of the type of bulb shown in the following figure.
That is to say, it is required that the damaged area of the glass lampshade should account for 75% of the area of the other parts of the lamp (glass lampshade+other accessories) except for the lamp head, rather than only accounting for 75% of the area of the glass lampshade as we understand it. And it also needs to be labeled. This is to avoid potential safety hazards due to fragmentation into flakes. To pass UL certification, the above requirements must be met.