What the jacket does in a fire
The copper or glass inside the cable carries the signal. The jacket decides what the cable gives off if it burns. PVC (polyvinyl chloride) is tough and inexpensive. When it burns it can produce dense smoke and halogen acid gases, which are harmful to people and corrosive to electronics.
LSZH stands for low smoke, zero halogen. These jackets are compounded to release less smoke and no halogen acid gas. They are widely specified in occupied commercial buildings, transport spaces, and enclosed risers for that reason. LSZH is not the same thing as a fire-resistant or circuit-integrity cable. It is a jacket behaviour, not a promise that the circuit will keep working in a fire.
| PVC | LSZH | |
|---|---|---|
| Halogen acid gas when burned | Yes | No |
| Smoke | Denser | Lower |
| Cost | Usually lower | Usually higher |
| Typical ask | Where the spec allows it | Occupied and enclosed spaces |
How this applies in Singapore
Singapore projects often call for LSZH on indoor copper and fibre, especially in commercial towers, campuses, and anywhere the specification refers to low-smoke halogen-free materials. That is a purchasing pattern, not a ruling. Whether a given riser, plenum, or escape route requires a particular flame, smoke, or halogen classification is decided by the project’s qualified person and the authority having jurisdiction, including the Fire Code and SCDF requirements that apply to that building.
Do not substitute PVC for LSZH, or the reverse, to save cost or to use up stock, unless the consultant or the specification allows it. The printed legend on the jacket and the manufacturer’s datasheet are what the inspector and the consultant will check.
AmberWork Source stocks both PVC and LSZH versions of many CommScope copper and fibre parts in Singapore. Quote the part number from the specification rather than the category alone, because the jacket is part of the part number.