Limiting Oxygen Concentration (LOC) Testing

What Limiting Oxygen Concentration (LOC) Testing Answers

This test determines the lowest oxygen concentration at which flame propagation can still occur for a specified fuel, inert gas, and set of test conditions. The result applies to the submitted material, mixture composition, temperature, pressure, and inert gas stated in the report. LOC isn’t a universal constant for a material; it can shift with fuel composition, concentration, temperature, pressure, humidity, and which inert gas is used, so we define the test basis explicitly before testing begins rather than reporting a single number without context.

Test Method and Standard

The gas or vapor mixture is prepared in an evacuated 20-L stainless steel spherical vessel using controlled partial pressure and, for suitable liquids, a heated vacuum evaporator. The vessel is brought to the specified temperature and mixed to promote a representative atmosphere, then tested across selected oxygen and fuel concentrations until the limiting boundary is established. Testing follows EN 1839 Method B for explosion limits and limiting oxygen concentration, and the vessel supports a temperature range of 20 to 120°C. The quotation identifies the governing method, inert gas, and test matrix before work begins.

What You Receive

• Limiting oxygen concentration (LOC) for the specified fuel, inert gas, and conditions
• Pressure-time data supporting the flame propagation determination
• Documented test conditions, mixture preparation basis, and inert gas used

How the Data Supports Decisions

This result supports selection of a safe maximum oxygen concentration for inerted operation, definition of oxygen alarm, trip, and interlock setpoints with an appropriate engineering margin, and evaluation of nitrogen, carbon dioxide, or other inerting strategies. It also informs purge and startup or shutdown procedure development, and helps assess whether a process change affecting fuel composition, temperature, pressure, or inert gas has shifted the safe operating range.

When to Order This Test

• Inerting is being considered or already used as an explosion prevention safeguard
• You need to validate an existing oxygen control basis against actual process conditions
• A change in fuel composition, temperature, pressure, or inert gas type may affect the allowable oxygen concentration

Sample Submission Guidance

Sample needs depend on material state, concentration matrix, vaporization efficiency, repeat testing, and the inert gas evaluated. HazBasis confirms sample quantity and handling requirements after reviewing the SDS and test scope. Include the SDS, composition and purity information, physical state and vaporization behavior, the operating temperature and pressure range, and the inert gas you intend to use.

Why Choose HazBasis

• LOC is a test result, not an operating setpoint on its own, and the gap between the two matters. We help translate the measured value into an actual operating limit that accounts for uncertainty, process variability, analyzer performance, response time, mixing, and sampling location, not just hand over a number.
• Nitrogen and carbon dioxide can produce genuinely different limiting behavior for the same fuel, so we confirm which inert gas your process actually uses before testing, rather than defaulting to whichever is more convenient in the lab.
• If your process temperature or pressure differs from standard reference conditions, we test at your actual conditions when that difference matters, since LOC measured at room temperature can understate the real risk at an elevated process temperature.

FAQ