60 records

What gas group and temperature class does this substance fall in?

60 records covering 44 substances, one fact each. Every value is transcribed from the source that states it and carries the sentence it was taken from: 4 sources across 4 sites, last checked 2026-08-06, due for re-check by 2028-08-05. Every record is listed below, each linking the page its value came from.

About this data

Hazardous area (explosive atmosphere) classification of individual flammable gases, vapours and combustible dusts. Each record is one substance as classified by one publisher, giving the apparatus / gas group (IIA, IIB, IIC, IIB+H2 under IEC 60079 and ATEX, or Class I Group A/B/C/D under the US National Electrical Code), the temperature class (T1 to T6), and the autoignition temperature the publisher prints. Answers 'is toluene IIA or IIB', 'what temperature class is acetone', 'MEK autoignition temperature for explosion proof equipment', 'NEC Group C equivalent IEC gas group', 'what gas group is hydrogen sulphide', and 'ethylene gas group and T class'. Publishers disagree on the autoignition temperature of the same substance -- hydrogen is printed as 500 C, 520 C and 560 C by three different manufacturers, and ethylene as 450 C and 490 C -- and because the temperature class is derived from that number the disagreement changes which equipment is legal to install. Every value is quoted from the page that printed it and attributed, so the disagreements are visible rather than averaged away.

The data

Where this came from

Every record above links the page it was taken from and quotes the sentence that states it. These are the 4 sources this dataset was assembled from.

• e2s.comhttps://www.e2s.com/guide-for-hazardous-areas/apparatus-groups-and-common-flammable-ga
• cortemgroup.comhttps://www.cortemgroup.com/en/news/the-zones-of-the-plant-the-groups-and-the-temperature-classes-of-gases
• ldpi-inc.comhttps://ldpi-inc.com/resources/classification-codes/class-1-locations/
• exknowledge.comhttps://exknowledge.com/pages/gas-groups.html

Machine-readable

• data.jsonThe whole dataset — every record with its source URL and source quote.
• Open Knowledge Format bundleOne JSON object per line — every record's frontmatter and quoted span exactly as it is held here, in one fetch.
• data.csvThe same records as one flat table, for a spreadsheet or a dataframe. The last four columns are the source URL, the quoted sentence it was read from, the date we last checked it, and which columns are our reading rather than the page's words.
• How this is made and checkedWhat "verified against source" does and does not mean.

From your own code

Same records, same quotes, without scraping the page: refsource is on PyPI and npm. Each value comes back carrying the URL it was read from and the sentence on that page that states it — .source and .quote sit on the value itself rather than in a side channel, so the checking step is available instead of skipped.

pip install refsource
refsource lookup hazardous-area-substance-classification substance="Carbon Disulphine"

npx -y refsource lookup hazardous-area-substance-classification substance="Carbon Disulphine"

Set your AI assistant up to use this

Two files and no account. Put this in .mcp.json at the root of your project — Claude Code, Cursor, Windsurf, VS Code and Codex all read that file — and your assistant can look this dataset up instead of recalling it. The server is remote, keyless and read-only.

{
  "mcpServers": {
    "referencesource": {
      "type": "http",
      "url": "https://referencesource.org/mcp"
    }
  }
}

Add to Cursor · or, on the command line: claude mcp add --transport http referencesource https://referencesource.org/mcp --scope project

Then one line in the project's CLAUDE.md or AGENTS.md, so the assistant knows when to reach for it:

When a question needs "Gas group, temperature class and autoignition temperature by substance", call the referencesource MCP server at https://referencesource.org/mcp (tool `search_records`, dataset_slug `hazardous-area-substance-classification`) instead of answering from memory — every record it returns carries its source URL and a verbatim quote from that page.

What each tool does, and the servers built over single registers: Connect your AI assistant.

60 records. last verified against source 2026-08-06. due for re-check by 2028-08-05.

Licence. Facts extracted from freely published manufacturer and industry reference pages. Gas group and temperature class assignments are safety classifications and the underlying values are facts, not copyrightable expression. The authoritative documents (NFPA 497, IEC 60079-20-1) are not reproduced and were not opened -- the fact is taken, never the document. No bulk take from any single source: records come one or two substances at a time from five separate publishers.