Category M 1 equipment must keep ignition sources inactive even in rare incidents, with two independent means of protection or protection against two independent faults; where needed it must be dust-tight; surface temperatures must stay clearly below the ignition temperature of foreseeable air and dust mixtures; and parts that may be ignition sources may be opened only when non-active or intrinsically safe, otherwise a warning label is required. Category M 2 equipment must keep ignition sources inactive in normal operation, including under more severe conditions such as rough handling and changing environments; parts that may be ignition sources may be opened only when non-active or through interlocks, with a warning label otherwise; and the M 1 dust requirements apply.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.