PVC can be formulated with flame retardants to meet certain vertical-burn or UL ratings, but when it burns it commonly produces dense black smoke and halogen-containing acidic gases that are hazardous to people and equipment. A PVC cable (made of polyvinyl chloride) has a jacket that gives off heavy black smoke, hydrochloric acid, and other toxic gases when it burns. Low Smoke Zero Halogen. This short guide explains the commonly used materials — LSZH and PVC — how industry fire-rating systems (plenum, riser, vertical flame tests) work, and practical tradeoffs so you can pick the right cable for the space and code requirements. The focus here is strictly on fiber cable fire ratings and. When selecting fiber optic patch cables for data centers, commercial buildings, or telecom facilities, you may often notice markings such as OFNP, OFNR, LSZH, and PVC on the cable jacket. These terms indicate important information about fire resistance, smoke emission, and installation. Flame retardant cables are designed to resist the spread of fire into a new area. There are designations FRNC / LSZH, FR / LSZH, FR / PVC and others.
[PDF Version]