Yes, optical cables used indoors are required to meet flame-retardant standards, with specific classifications depending on installation location and regulatory codes.

Overview of Requirements

Indoor optical fiber cables must have flame-retardant jackets to prevent fire propagation and reduce smoke and toxic gas emissions during a fire . The requirements vary depending on the cable's intended use:

• Plenum-rated cables (OFNP/OFCP): Designed for air-handling spaces, these cables must meet the strictest flame and smoke standards, such as NFPA 262 or the former UL-910, ensuring minimal flame spread and smoke generation .
• Riser-rated cables (OFNR/CMR): Intended for vertical runs between floors, these cables are tested for vertical flame propagation using standards like UL 1666 or IEC 60332, which are less stringent than plenum tests but still prevent sustained flame travel .

Testing and Certification

Flame-retardant optical cables are tested and certified by Nationally Recognized Testing Laboratories (NRTLs) such as UL or Intertek (ETL) to ensure compliance with the National Electric Code (NEC) and other safety standards . Key testing standards include:

• UL 1651: Covers optical fiber cable performance, including flame resistance, marking durability, and compliance with NEC Articles 770 and related sections .
• UL 1666 / NFPA 262: Measure vertical flame propagation and smoke generation for riser and plenum cables .
• IEC 60332: International standard for vertical flame tests on single cables .
• IEC 61034 and IEC 60754: Measure smoke density and halogen-acid emissions, important for low-smoke, halogen-free (LSZH) cables .

Regional and International Considerations

In Europe, flame-retardant performance is classified under the Construction Products Regulation (CPR), with classes ranging from Eca to B1ca, and vertical flame propagation tests are adapted for thin fiber optic cables . Manufacturers often perform additional fire tests to ensure compliance with local building codes and safety regulations.

Practical Implications

When planning installations:

• Plenum spaces (air-handling areas) require plenum-rated cables.
• Riser shafts (vertical runs between floors) require riser-rated cables.
• LSZH cables are preferred in enclosed public spaces, hospitals, and data centers to reduce smoke and toxic gas exposure . Always verify the cable's certification and test reports from recognized laboratories to ensure compliance with local codes and safety standards.