Before a gas, solvent vapour or dust-handling process can be assessed for explosion risk, two numbers are needed: the flammability limits - the leanest and richest mixtures that propagate a flame - and the auto-ignition temperature at which a mixture ignites without a spark. Motis covers this test family with flammability limit apparatus to ASTM E681 and high-temperature/pressure configurations to ASTM E918 and EN 1839, together with auto-ignition testing.
How the Auto-Ignition and Flammability Limit Tester works
For limit testing, a prepared mixture of the test gas or vapour with air fills a closed vessel at the set temperature (and pressure, for elevated-condition methods). An ignition source is fired inside the vessel and flame propagation away from the source is observed; the mixture is adjusted stepwise until the boundary between propagation and non-propagation is found. Auto-ignition testing introduces the sample into a heated vessel and finds the lowest temperature at which ignition occurs without an ignition source.
Key specifications
| Standards covered | ASTM E681 (flammability limits at ambient conditions), ASTM E918 and ASTM E2079 (elevated temperature and pressure), EN 1839 (flammability limits) |
|---|---|
| Test types | Lower and upper flammability limits; auto-ignition temperature |
| Vessels | Closed test vessels and explosion chambers sized to the method ordered; confirm vessel volume and pressure rating against the datasheet |
What the test reports
- Lower flammability limit (LFL) and upper flammability limit (UFL)
- Auto-ignition temperature
- Flame propagation observations at each mixture step
Applications
Chemical, petrochemical, refrigerant and process-safety laboratories use these instruments to characterise new compounds, refrigerants and solvent systems for safety data sheets and hazardous-area assessments.
Frequently asked questions
Which standard should I order against?
Order against the standard your reports must cite. The instrument platform is shared across the listed standards, but fixtures, software templates and calibration routines differ, so name the standard (and its year) in your inquiry and the configuration will be matched to it.
Which method matches my safety data sheet requirement?
SDS flammability data are commonly quoted from ASTM E681 or EN 1839 at ambient conditions; elevated temperature or pressure data come from ASTM E918/E2079. Tell us the conditions your assessment needs and we will match the vessel configuration.
Can the apparatus handle corrosive or toxic gases?
Gas compatibility depends on vessel and seal materials. Name the gases you intend to test in your inquiry so compatibility can be confirmed before quotation.
Configuration, installation and support
Every Auto-Ignition and Flammability Limit Tester is supplied as a configured system, not a bare instrument: the test chamber or frame, the burner or heater assemblies named in the method, the measurement chain and the control software with the report templates for ASTM E681, ASTM E918, ASTM E2079, EN 1839. Before quotation we confirm the installation conditions with you - floor loading and ceiling height for large rigs, exhaust and extraction routes, gas and fuel services, and power supply - because a fire test instrument only produces defensible data when the room around it is right. Commissioning covers assembly, calibration of the measurement chain against the method's own checks, and training of your operators on running the test and maintaining the apparatus. Spare ignition parts, thermocouples and other consumables for the first period of operation can be included in the supply, and the instrument is supported with calibration and maintenance services after installation.
What to include in your inquiry
To quote the Auto-Ignition and Flammability Limit Tester correctly the first time, send: the standard and edition you will test to (ASTM E681, ASTM E918, ASTM E2079, EN 1839); the materials or products you will test and their sizes; the configuration options you already know you need; and the destination laboratory's location and available services. If you are building a new fire laboratory rather than adding one instrument, say so - this apparatus is often planned together with the other instruments in its category, and a combined layout and exhaust plan is cheaper than three separate ones.