Limiting Oxygen Index Chamber (LOI)
Limiting Oxygen Index Chamber (LOI) – ToronFT™ LOI
ToronFT™ LOI Limiting Oxygen Index Chamber (LOI) is a precision laboratory instrument for determining the oxygen index (limiting oxygen concentration) of a wide range of solid and sheet materials. The oxygen index is one of the most widely used parameters for characterizing the flammability of plastics, polymers, textiles, and composite materials — providing a quantitative measure of the minimum oxygen concentration in an oxygen/nitrogen mixture required to sustain combustion of a material under defined test conditions.
The ToronFT™ LOI features a UK-imported oxygen concentration sensor with direct digital readout and a resolution of 0.1%, ensuring fast, precise oxygen index determination without the need for manual interpolation. It complies with JIS 7201, BS 2782, ANSI/ASTM D2863, and ISO 4589-2, making it suitable for international material qualification, quality control, and research programs.
Limiting Oxygen Index Chamber (LOI) – ToronFT™ LOI Applications
The ToronFT™ LOI Limiting Oxygen Index Chamber (LOI) is applicable for oxygen index determination of the following material types:
- Strip or sheet materials with thickness up to 10.5 mm that can stand upright and support themselves for standard oxygen index testing
- Homogeneous solid materials, laminated materials, foam materials, soft sheets, and film materials with apparent density greater than 100 kg/m³
- Foam materials with apparent density less than 100 kg/m³ — oxygen index test method supported
- Sheet materials and films that can be supported upright, using oxygen index testing to determine ease of combustion when in contact with flame in air
- Plastics, rubbers, and polymeric composites requiring flammability classification by oxygen index for product development or certification
- Textiles, nonwovens, and fiber-reinforced materials for oxygen index-based flammability characterization
Standards
The ToronFT™ LOI is designed to comply with the following international oxygen index test standards:
- ISO 4589-2: Plastics: Determination of burning behaviour by oxygen index — Part 2: Ambient-temperature test
- ASTM D2863: Standard Test Method for Measuring the Minimum Oxygen Concentration to Support Candle-Like Combustion of Plastics (Oxygen Index)
- BS 2782-1: Method 141A — Determination of the flammability of plastic film
- JIS K 7201-2: Plastics: Determination of burning behaviour by oxygen index
Limiting Oxygen Index Chamber (LOI) – ToronFT™ LOI Key Features
- Direct digital readout oxygen index display with 0.1% resolution — UK-imported oxygen concentration (oxygen index) sensor provides immediate, accurate measurement without manual interpolation or calculation
- Dual-pressure-gauge system independently displays oxygen output pressure and nitrogen output pressure, enabling precise and independent adjustment of each gas supply for accurate oxygen index mixture preparation
- Wide flow measurement range of 0–100% O₂ / N₂ with a resolution of 0.1 L/min and measurement accuracy of Level 2.5 — meeting the precision requirements of ISO 4589-2 and ASTM D2863
- Quartz glass combustion tube with inner diameter 75 mm and height 450 mm provides the standard geometry and thermal resistance needed for reliable oxygen index combustion tests
- Standardized gas flow conditions: 90 mm/s ± 10 mm/s at the top of the combustion tube and 40 mm/s ± 2 mm/s within the tube — fully compliant with ISO 4589-2 and ASTM D2863 flow requirements
- Mixed-gas rotameter (can display oxygen or nitrogen separately) provides visual flow rate confirmation alongside the digital oxygen index readout
- Input pressure adjustable from 0.25 to 0.5 MPa via the needle valve and regulating valve, accommodating a range of laboratory gas supply pressures
- Suitable for a broad range of specimen types including strips, sheets, foams, laminates, and films — covering nearly all material categories addressed by ISO 4589-2 and ASTM D2863
- Complies with JIS 7201, BS 2782, ASTM D2863, and ISO 4589-2, providing internationally recognized oxygen index test results for North American and global markets
Theory and Method
The oxygen index test determines the minimum concentration of oxygen (expressed as a percentage of an oxygen/nitrogen mixture by volume) required to support continued downward combustion of a material specimen under standardized conditions. A specimen is mounted vertically in the combustion tube, and a precisely controlled oxygen/nitrogen gas mixture is flowed upward through the tube. The top of the specimen is ignited, and the oxygen concentration is progressively adjusted until the minimum concentration sustaining a candle-like flame for a defined burn time or length is found — this is the oxygen index value.
The ToronFT™ LOI uses a UK-imported oxygen concentration sensor to provide real-time digital readout of the oxygen index concentration directly, with a resolution of 0.1%. The quartz glass combustion tube (inner diameter 75 mm, height 450 mm) provides a thermally stable and optically clear test environment. Gas flow rate at the top of the combustion tube is 90 mm/s ± 10 mm/s, and within the tube 40 mm/s ± 2 mm/s, ensuring the standardized flow conditions required by ISO 4589-2 and ASTM D2863. Input pressure is adjustable from 0.25 to 0.5 MPa via the regulating valve.
Limiting Oxygen Index Chamber (LOI) – ToronFT™ LOI Technical Specifications
| Component / Parameter | Specification Details |
|---|---|
| General Information | |
| Product Name | Limiting Oxygen Index Chamber (LOI) — ToronFT™ LOI |
| Model | ToronFT™ LOI |
| Compliance Standards | ISO 4589-2; ASTM D2863; BS 2782; JIS K7201 |
| Measurement & Gas Control System | |
| Oxygen Concentration (Index) | Range: 0–100%; Resolution: 0.1% |
| Display | Digital readout, direct reading |
| Oxygen Index Sensor | Imported from the UK |
| Flow Measuring Range | 0–100% O₂/N₂ |
| Flow Measurement Accuracy | Level 2.5 |
| Flow Resolution | 0.1 L/min |
| Rotameter | Mixed gas (oxygen or nitrogen displayed separately); Range: 2.5–25 L/min; Resolution: 0.5 L/min |
| Input Pressure Range | 0.25–0.5 MPa (adjustable) |
| Pressure Gauges | Two (oxygen output pressure and nitrogen output pressure) |
| Gas Source Requirements | Oxygen (purity ≥98%) and Nitrogen (supplied by the buyer) |
| Combustion Chamber & Test System | |
| Combustion Tube Material | Quartz glass |
| Combustion Tube Dimensions | Inner Diameter: 75 mm; Height: 450 mm |
| Gas Flow Rate (Tube Top) | 90 mm/s ± 10 mm/s |
| Gas Flow Rate (Inside Tube) | 40 mm/s ± 2 mm/s |
| Igniter | Propane electronic igniter; Flame height adjustment: 16 mm ± 4 mm |
| Sample Clamps | One set each of rigid self-supporting clamps and soft material clamps |
| Timer Accuracy | ±0.1 s/h |
| Operating Conditions & Dimensions | |
| Ambient Temperature | -10°C to 45°C |
| Relative Humidity | <85% |
| Voltage | 220V, 50Hz, 150W (110V is also available) |
| Equipment Dimensions | 550 mm × 350 mm × 680 mm (L × W × H) |
For more information, pricing, or to request a quotation, please contact ToronFT. Specifications are subject to change without prior notice.