The EN50399 standard specifies test equipment and test methods for the evaluation of flame spread, heat release, and smoke generation characteristics of vertically mounted bunched wires, cables, or optical cables under specified test conditions. Corning Optical Communications manufactures quality flame retardant optical fiber cables for indoor applications, which comply with the requirements of the National Electric Code® (NEC® 2023) published by the National Fire Protection Agency (NFPA). In the EN50399 test, the cable is installed on the. certification, UL is the leading resource for fire safety technologies. 1 This is a fire-test-response standard.