Oxygen Index Tester COI Series

Overview

The COI Series Oxygen Index Tester is a precision benchtop combustion analysis instrument engineered for the quantitative determination of the minimum oxygen concentration—expressed as volume percent—in an oxygen–nitrogen mixture required to support candle-like combustion of a material under specified test conditions. Based on the principle of limiting oxygen index (LOI) measurement per ASTM D2863 and ISO 4589-2, the system delivers high reproducibility in evaluating flame retardancy and relative combustibility of solid polymeric materials including thermoplastics, thermosets, elastomers, textiles, bituminous compounds, and composite laminates. The instrument operates via controlled upward gas flow through a vertical specimen holder, where ignition is initiated by a standardized flaming source; the LOI value is defined as the lowest O₂ concentration at which the specimen sustains burning for ≥3 minutes or consumes ≥50 mm of length. This method provides a fundamental, comparative metric widely adopted in R&D labs, quality control environments, and regulatory testing facilities.

Key Features

• Integrated digital mass flow control architecture enabling precise, independent regulation of oxygen and nitrogen supply streams—total combined flow maintained at 10.6 L/min with real-time feedback.
• External electrochemical oxygen sensor with linear response, factory-calibrated traceability, and modular design permitting rapid field replacement without system recalibration.
• O₂ concentration adjustment resolution of 0.2% (v/v), exceeding the 0.4% step capability typical of conventional domestic units—critical for high-fidelity LOI determination near threshold values.
• Dual-channel digital display showing real-time O₂ concentration (%), nitrogen mass flow rate (L/min), and total gas flow (L/min) with 0.1% resolution and ±0.1% full-scale accuracy.
• Response time <3 seconds for O₂ sensor output—ensuring dynamic stability during rapid concentration transitions and minimizing test cycle variability.
• Robust stainless-steel combustion chamber with integrated flame arrestor, specimen holder alignment gauge, and standardized burner tip geometry compliant with ISO 4589-2 Annex A.

Sample Compatibility & Compliance

The COI Oxygen Index Tester accommodates standard test specimens per ASTM D2863 (150 × 10 × 10 mm) and GB/T 2406 (150 × 10 × 4 mm), supporting rigid plastics, flexible foams, woven/nonwoven textiles, rubber sheets, and asphalt-coated substrates. All mechanical and pneumatic subsystems are designed to meet dimensional, thermal, and flow uniformity requirements specified in ISO 4589-2 Clause 6 and GB/T 2406.2–2009. Instrument validation protocols align with GLP principles, and raw data outputs—including time-stamped O₂ readings, flow profiles, and pass/fail combustion observations—are structured to support audit-ready documentation for internal QA, third-party certification (e.g., UL, SGS), and regulatory submissions requiring traceable combustion performance evidence.

Software & Data Management

While the base COI model operates via embedded firmware with local digital readouts, optional USB data logging firmware enables timestamped export of O₂ concentration, N₂ flow, total flow, and manual test annotations (specimen ID, operator, date/time) to CSV format. Exported datasets are compatible with common statistical analysis platforms (e.g., Minitab, JMP) and support trend analysis across material batches or formulation iterations. For laboratories operating under FDA 21 CFR Part 11 or ISO/IEC 17025 frameworks, the optional PC-based control module provides electronic signature capability, audit trail generation, and user-access-level configuration management—fully traceable from instrument initialization to final report generation.

Applications

• Formulation screening of flame-retardant additives (e.g., phosphorus-, bromine-, or mineral-based systems) in polyolefins, PVC, and engineering resins.
• Comparative assessment of LOI shifts following UV aging, thermal cycling, or humidity exposure per ASTM G154/G155.
• Quality conformance verification of incoming polymer pellets or finished components against contractual LOI specifications (e.g., ≥28% for V-0 rated enclosures).
• Supporting fire safety documentation for building products under EN 13501-1 or ASTM E84/E136 pathways.
• Academic research into structure–combustion property relationships in bio-based polymers and nanocomposites.

FAQ

What standards does the COI Oxygen Index Tester fully comply with?
It meets all technical and procedural requirements of GB/T 2406.2–2009, ASTM D2863–22, ISO 4589-2:2017, BS 2782-1:1995 Method 141, and NF T51-071:2014.
Is calibration certificate included with shipment?
Yes—a NIST-traceable calibration certificate for the electrochemical O₂ sensor and flow meters is provided, valid for 12 months from date of issue.
Can the instrument be integrated into a laboratory LIMS environment?
Via optional RS-232 or USB-to-serial interface, raw sensor and flow data can be parsed and ingested by LIMS platforms supporting ASCII-based protocol ingestion.
What maintenance is required for sustained accuracy?
Annual sensor verification using certified gas mixtures (e.g., 21.0% O₂ in N₂) is recommended; the external sensor module allows replacement in <5 minutes without tools.
Does the system support automatic pass/fail evaluation based on user-defined LOI thresholds?
Manual interpretation remains standard per ASTM D2863; however, the optional PC software module supports configurable alert thresholds and auto-flagging of results outside preset tolerance bands.