Ⅱ、 Detailed explanation of each testing item

　　‌Class A – Limited Flame Spread‌

　　This is the basic test that all protective clothing certified by EN ISO 11612 must meet. After brief exposure to flames, the flame spread range, residual flame time, and residual combustion time of the material must be controlled within the specified limits. This test ensures that clothing does not continue to burn or spread when accidentally exposed to flames, giving the wearer time to escape danger.

　　Class B – convective heat protection‌

　　Evaluate the material’s ability to block high-temperature gas or flame convective heat transfer. During testing, fix the sample above the flame and record the time required for the internal surface temperature to rise by 24 ° C using a calorimeter. The longer the time, the higher the level of protection. B1 level is suitable for low-intensity brief exposure, while B3 level is suitable for more severe convective heat environments.

　　Class C – Radiation Heat Protection‌

　　Evaluate the material’s ability to block infrared radiation heat. During testing, expose the sample to a controlled radiation heat source and measure the time required for the internal surface temperature to rise by 24 ° C. C1 is the lowest level and C4 is the highest level, suitable for work scenarios with strong radiation heat sources such as casting and steel smelting.

　　‌Class D – Molten Aluminum Splash Protection‌

　　Regarding the risk of molten aluminum splashing in industries such as aluminum processing, automotive manufacturing, and aerospace. During testing, pour 780 ° C molten aluminum onto the fabric and place a thin film underneath to simulate human skin. The criterion for judgment is whether the film remains intact after testing. The grading of D1 to D3 depends on the amount of molten metal that the fabric can withstand.

　　Class E – Molten Iron Splash Protection‌

　　Regarding the risk of molten iron splashing in steel casting and heavy metal processing. The testing method is similar to Class D, but using molten iron at approximately 1400 ° C and PVC film as a simulated skin layer. The level of E1 to E3 also depends on the amount of metal it can withstand.

　　Class F – Contact Thermal Protection‌

　　Evaluate the protective ability of materials against direct contact with high-temperature objects. During testing, the fabric is in contact with a heating element at 250 ° C and the time required for the inner surface temperature to rise by 10 ° C is measured. F1 level can provide protection for 5 to 10 minutes, while F3 level can provide protection for more than 15 minutes, suitable for operating environments that may come into contact with high-temperature pipelines, equipment, or tools.

　　Ⅲ、 Certification and Market Access

　　EN ISO 11612 is a coordinated standard under the framework of the European Union’s Personal Protective Equipment Regulation (EU) 2016/425. Protective clothing must pass the various tests specified in this standard in order to enter the EU market and bear the CE mark. The certification process usually includes: determining the product type and applicable level, preparing technical documents, selecting EU notified bodies for type testing, establishing an internal production control system, and signing a declaration of conformity. Only by completing the above steps can the product be legally launched in the European market.

　　Ⅳ、 Usage and maintenance

　　Certified protective clothing must be worn, cleaned, and maintained according to the manufacturer’s instructions. Improper cleaning methods or excessive use may reduce protective performance. Some tests may require samples to undergo a specified cleaning cycle before testing to verify the performance retention ability of the clothing after repeated use. Users should regularly check the integrity of their clothing and replace it promptly if any damage, severe contamination, or performance degradation is found.