Steiner Tunnel Test Furnace for Optical Fibre Cable UL 910

Steiner Tunnel Test Furnace for Optical Fibre Cable UL 910 measures flame spread and smoke density for insulated and jacketed electrical wires, cables, and optical fiber cables intended for use in plenums and other air-handling spaces without raceway enclosures.

The National Electrical Code (NEC) 800 classifies fire ratings for cables as CMP, CMR, CMG, CM, and CMX:

• CMP (Plenum) Cables – Designed for installations in air ducts, suitable for commercial and residential spaces. These cables are flame-resistant and do not contribute to fire spread.
• CMR (Riser) Cables – Used for standard networking between rooms, provided they do not pass through air ducts.
• CM/CMG Cables – The most commonly used commercial-grade communication cables.
• CMX Cables – Intended for residential or small-scale applications with minimal communication cable requirements.

CMP is the highest-rated cable under NFPA/UL fire standards, meeting the strict requirements of NFPA 262 and UL 910. The test involves placing multiple cable samples in a horizontal duct and exposing them to an 87.9 kW gas Bunsen burner (300,000 BTU/hr) for 20 minutes. To pass, the flame must not spread beyond 5 feet from the burner’s front edge.

CMP cables are commonly installed in air return pressurization systems within ventilation ducts or air-handling equipment. They are approved for use in both Canada and the U.S.

FEP/plenum materials that meet NFPA 262 / UL 910 standards offer superior flame resistance compared to low-smoke, halogen-free materials conforming to IEC 60332-1 and IEC 60332-3, while also producing less smoke when burned.

Steiner Tunnel consists of

• Steiner Tunnel Furnace – SUS304 Stainless Steel Construction
• Constructed from SUS304 stainless steel with a firebrick-lined interior for enhanced flame resistance and thermal insulation.
• Double-layer, high-temperature-resistant glass observation window for monitoring and recording flame spread.
• Indicators on each window for accurate flame spread distance measurement.
• Cooling water circulation support bracket to stabilize burning samples.
• 2mm-thick SUS304 stainless steel water-sealing tank to prevent smoke leakage during testing.
• Stainless steel insulated top cover, lined with high-temperature firebrick for optimal insulation.
• Independent multi-functional exhaust pressure detection device for real-time monitoring, with a measurement range of 0–250Pa and accuracy of ±0.5Pa (system schematic test accuracy: ±2Pa).
• Frequency converter to regulate airflow, ensuring a minimum flow rate of 8,000 m³/h for efficient smoke extraction.
• U-shaped gas burner delivering a standard 5.3MJ/min flame source, adjustable via a flowmeter with a measuring range of 0–160L/min.
• High-voltage ignition system (44KV, 50mA) with a minimum electrode voltage of 1.8kVp for reliable ignition.
• Smoke measurement system with an independent signal processor to maintain sensor accuracy.
• Automatic recording of temperature and smoke sensor data at a 1Hz sampling rate.
• Standard test software for automated tracking of air velocity, temperature, smoke density, and other test parameters.