Gas Group & Temperature Class Checker
Screen the gas group and temperature class separately, using reference substance data or your documented auto-ignition temperature. This tool does not classify an area or approve a luminaire.
No matching reference entry. Try another name or enter your documented AIT.
Multiple selections screen each substance independently. They do not calculate the properties of a gas mixture.
Use the accepted value for your substance and project conditions. AIT alone cannot determine gas group.
Copy the zone from approved project documents. It does not change the gas-group or temperature calculation.
Your screening result
Two independent checksSelect a substance to begin.
Product families to review
Use the screening result to request the exact model, temperature rating, ambient range and certificate schedule.
Your enquiry summary
Copy this screening summary to include with your model enquiry.
How the two checks work
Gas group follows the substance
Gas grouping uses ignition and flame-transmission characteristics, including MESG and MIC criteria. Within the applicable certified scope, IIC equipment covers IIC, IIB and IIA gas-group requirements. Group coverage does not establish temperature or zone suitability.
Understand IIB and IICTemperature is a separate check
This tool selects the first T-class whose surface-temperature ceiling is strictly below the reference AIT. At AIT 450°C, it returns T2 rather than T1. The displayed temperature difference is arithmetic, not a validated safety margin.
Read the selection methodHydrogen + diethyl ether: different controlling substances
Hydrogen controls the group: IIC. Diethyl ether controls temperature: AIT 175°C, screened against T4 at 135°C. The temperature difference is 40°C. This is separate-substance screening, not a mixture assessment.
Reference values behind the result
Checked on 2026-11-05 against the sources below. Values describe reference substances; use accepted project data for the actual composition and conditions.
Substance lookup
| Substance | Group | AIT °C | Screened class |
|---|---|---|---|
| Hydrogen | IIC | 560 | T1 |
| Methane (industrial) | IIA | 600 | T1 |
| Propane | IIA | 450 | T2 |
| Acetylene | IIC | 305 | T2 |
| Ethylene | IIB | 440 | T2 |
| Ethanol | IIB | 400 | T2 |
| Hydrogen sulfide | IIB | 260 | T3 |
| n-Hexane | IIA | 225 | T3 |
| Diethyl ether | IIB | 175 | T4 |
| Carbon disulfide | IIC | 90 | T6 |
Temperature-class ceilings
| Class | Maximum surface °C |
|---|---|
| T1 | 450 |
| T2 | 300 |
| T3 | 200 |
| T4 | 135 |
| T5 | 100 |
| T6 | 85 |
At AIT 85°C or lower, none of these ceilings is strictly below the input. The tool returns a specialist-review result, not T6.
Questions before you specify
Does hydrogen lighting always need T6?
No. With this reference AIT of 560°C, T1's 450°C ceiling passes the temperature-only screen. Hydrogen requires IIC gas-group suitability, unless an applicable specific-gas marking covers the use. The final equipment must also satisfy the project's other requirements.
Can AIT alone determine the gas group?
No. AIT supports the temperature check. Gas grouping depends on separate substance-classification data, including MESG and MIC criteria. The custom-AIT mode leaves gas group undetermined.
What happens when more than one substance is selected?
The tool selects the most demanding listed gas group and the lowest listed AIT independently, naming the controlling substances. This screens separate known substances only. Actual mixtures need their own accepted classification and ignition data.
Can IIB + H2 replace an IIC marking?
Not as a general substitution. A certified specific-gas marking such as IIB + H2 can cover hydrogen within its stated scope; it does not establish coverage for every IIC substance. No TORMIN IIB + H2 product is asserted here.
Can this result replace area classification or product approval?
No. Use approved area-classification documents and the exact product's certificate, schedule, instructions and nameplate. The optional zone input only displays a reference protection-level reminder; it never assigns a zone or generates a complete Ex marking.
Limits & sources
IEC-based industrial gas and vapour screening only. Dust, mining firedamp, oxygen-enriched conditions, actual mixture properties and installation approval are outside this tool. IEC 60079-20-1:2010 is an archived reference edition, replaced by ISO/IEC 80079-20-1:2017; use the edition adopted by your project. A source check date is not a claim of current product certification.
- NSW TestSafe: gas and vapour classification table - eight listed substance entries; the page references AS/NZS or IEC 60079-20-1.
- IEC 60079-20-1:2010 - hydrogen sulfide, CAS 7783-06-4, data table p.74: IIB, 260°C. Publication record and successor information.
- IEC 60079-0:2007 - archived reference for gas-group coverage and temperature classes; verify the applicable equipment edition.
- Directive 1999/92/EC, Annex II - zone/category reference, subject to risk-assessment provisions.
- TORMIN nameplate and certificate guide - compare the exact offered configuration with its supporting documents.