Your Printed Wiring Board fireproof?

Your Printed Wiring Board fireproof?

      Maybe you would find “FR-4 94V-0 in the silkscreen on your boards .FR-4 represents the substrate material using. And what is 94V-0  that for exactly?

       Released by Underwriters Laboratories of the United States,UL 94, the Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances testing. And it is a very important standard in the Printed Wiring Board Industry.  The standard determines the substrate materials tendency to either extinguish or spread the flame once the specimen has been ignited.


     The substrate materials are divided into 2 different kinds according to the UL 94 standard, flame retardant and non flame retardant.

Flame Retardant: 94V-2,94V-1,94V-0 ( 94V-0 is the highest fire-rating)

Non Flame Retardant: 94 HB.


     The higher the fire-rating, the higher the safety of the devices. And that leads to a higher cost for them.
     Besides the 94HB materials are knocked out by most Printed Wiring Board fabrication houses for the safety concern.

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