It is the highest safety in CMP fire rating, with perfect flame retardant ability, and will not emit a lot of toxic smoke when burning. CMP standard is UL910. according to UL definition, under the condition of forced intensive combustion of fans, a bundle of CMP wires and cables must be self-extinguished within 5 meters of combustion diffusion.
UL910/NFPA 262 horizontal tunnel furnace conforming to NFPA 262, UL910 and other standards is mainly used for testing the flame retardant performance of CMP grade wires and cables, and is mainly used for cables in horizontal subsystems that are directly laid in ventilated or forced ventilation environment without using metal pipelines. The flame retardant test standard represents the most stringent flame retardant test standard of UL in the United States, and even the whole wire and cable flame retardant test, and only the cable with fluorine sheath can pass the flame retardant test method.
The equipment box is made of 304 stainless steel, and its internal structure is brick, which is paved with high-temperature resistant and heat-insulating materials. Double-layer quartz glass observation window is provided to instantly observe and record the flame spread. Independent multifunctional exhaust pressure detection device, real-time monitoring and testing process, high precision. Automatic ignition system reduces manual operation and ensures the safety of test.

More details please refer to https://www.firetestingequipment.com/steiner-tunnel-test-apparatus.html