Ex Marking Decoder & Temperature Class / Gas Group Judgement Tool
Decodes an IEC 60079-0 Ex marking string field by field, and — once you select a process substance — judges temperature-class and gas-group suitability separately to determine a final PASS/FAIL.
1. Decode Ex Marking
Enter the Ex marking string exactly as printed on the nameplate. Example: Ex db IIB T4 Gb
Or build it by selecting each field (no need to know the syntax)
Or type the nameplate string directly
2. Temperature Class & Gas Group Judgement
Decoding a marking above auto-fills the equipment T-Class and gas group. Select a process substance (or enter manually) to judge temperature-class suitability and gas-group suitability separately — both must pass for a final PASS.
Equipment (per nameplate)
Process Substance
Substance DB: ArcSafe KGS Calculator internal data (per KGS GC101:2026 / IEC 60079-20-1 / NFPA 497 / KOSHA, 102 substances)
T-Class Reference Table
| Class | Max Surface Temp. | Example Gases (AIT > 200°C) |
|---|---|---|
| T1 | ≤ 450°C | Hydrogen, acetylene, etc. (AIT > 450°C) |
| T2 | ≤ 300°C | Ethylene, etc. |
| T3 | ≤ 200°C | Gasoline, crude oil, propane, etc. |
| T4 | ≤ 135°C | Acetaldehyde, diethyl ether, etc. |
| T5 | ≤ 100°C | - |
| T6 | ≤ 85°C | Carbon disulfide, etc. (very low AIT gases) |
Judgement Principle
The equipment's maximum surface temperature must be lower than the process gas's auto-ignition temperature (a higher T-number means a stricter class: T1 is the most lenient, T6 the strictest). This tool is for reference screening only — final determination must go through a certified certificate (ATEX/IECEx, etc.) and review by a qualified engineer.Protection Type Code Reference
| Code | Protection Type |
|---|---|
| d | Flameproof enclosure |
| e | Increased safety |
| ia / ib / ic | Intrinsic safety (Zone 0/1/2) |
| n | Non-sparking (Zone 2 only) |
| p / px / py / pz | Pressurized enclosure |
| ma / mb / mc | Encapsulation |
| o | Oil immersion |
| q | Powder filling |
| s | Special protection |
Dust Protection Grades (Korean KS notation)
The IEC scheme uses EPL (Da/Db/Dc), but domestic Korean (KS) notation sometimes uses the following dust-protection grades alongside it.
| Code | Grade |
|---|---|
| SDP | Special dust protection |
| DP | Dust protection |
| ZDP | Zone dust protection |
Relationship to Korean domestic certificates
Korea joined the IECEx Scheme (international mutual-recognition system for explosion protection) in June 2000, and KOSHA operates as an ExCB (Certification Body) and ExTL (Testing Laboratory). Actual Korean-issued safety certificates state the protection structure in the same order as international IEC 60079-0 — e.g. "per domestic notice, the explosion-protection structure corresponds to Ex ia IIC T4" (Ex → protection type → gas group → temperature class). In other words, the notation this tool uses applies equally to Korean KCs certification and to overseas ATEX/IECEx certification. Older domestic certificates, however, sometimes omit the EPL suffix (e.g. Gb).