UL flammability ratingIt is a product safety certification formulated by UL Company in the United States. It is used to judge the performance of different materials or products in fires. It can be regarded as a product's "fire prevention test report card". The higher the level, the stronger the fire prevention ability.

In the PCB industry,UL fire protection rating is directly related to the safety, reliability and market access of circuit boards.& nbsp;

★ UL 94V-0 for the PCB industry

Unlike ordinary plastics, the minimum entry requirement for most PCB substrate materials (especially the most commonly used FR-4) is UL 94 V-0. Mainly because there is current and heat inside the PCB, it is necessary to ensure that the board itself will not become a continuous source of combustion when the PCB is ignited at abnormal high temperatures or short circuits, and can quickly self-extinguish to prevent the spread of the fire., Therefore,V-0 is the lifeline of PCB product safety.

📍Common levelsFrom low to high, there are mainly HB, V-2, V-1, V-0, 5VA/5VB.

HB: It means that it is not fireproof.

 V-0 : Is an entry requirement for many electronic products (goes out within 30 seconds after leaving the flame).
5VA/5VB : It is the highest level and has strong resistance to flames.

★ Special test of PCB materials: copper clad laminate test

This is the most critical and special test in the PCB industry. It evaluates the final product form of "copper clad laminate" rather than just the resin or fiberglass cloth.

Test object 

The copper foil etched substrate (Prepreg) and the pressed copper clad laminate (CCL).

Test severity 

 The test is more stringent than ordinary plastics. It simulates the fire resistance of PCB in real working environments (such as electricity, components).

📍Key certifications 

Materials that pass this test will receive a "UL Document Number"(e.g., E 123456). This is the "ID card"(UL file number) that PCB manufacturers must check when selecting materials.

★ What do you think of the UL certification mark on the PCB?

On a compliant PCB,UL certification information usually needs to be reflected on the board.

UL mark or approval number

The PCB manufacturer's UL logo or factory approval number will be printed on the board in text or other form (e.g."E123456"), and will usually be specifically explained if the customer needs it.

Substrate grade mark:

The silk screen layer of many PCBs marks the substrate material and fire resistance rating, the most common being "FR-4" or "UL 94V-0".

Simply put, in the PCB industry, choosing materials with the correct UL fire protection certification is not a "high standard", but an "entry permit". It is the first and most important firewall to ensure the safety and reliability of electronic products.