For gas, vapour and mist atmospheres, category 1 equipment must prevent ignition sources from becoming active even in rare incidents, with two independent means of protection or protection against two independent faults; surfaces that may heat must not exceed the stated maximum temperature even in the most unfavourable circumstances; and parts that may be ignition sources may be opened only when non-active or intrinsically safe, otherwise a warning label is required. For dust atmospheres, ignition of air and dust mixtures must not occur even in rare incidents, dust may enter or leave only at designated points where needed, surface temperatures must stay well below the ignition temperature of foreseeable mixtures, and the safe opening rule applies.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.