Construction materials must not trigger an explosion under foreseeable operating stresses; within the manufacturer's operating limits they must not react with the constituents of the potentially explosive atmosphere in a way that impairs protection; and they must be chosen so that foreseeable changes in their characteristics and compatibility with other materials do not reduce protection, taking particular account of corrosion and wear resistance, electrical conductivity, mechanical strength, ageing and temperature variation.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.