HAC* vs ignition source

*HAC stands for hazardous area classification.
Question: shall we take into consideration in case of HAC, if there is any ignition source present or not? do we Ex classify an area where is Ex hazardous environment, but no ignition source at all?

Answer is definitely YES. pls take a look at all the pentagon (dust) and triangle (gas) above. If all exist, there is an explosion and not a hazardous environment only.
Keep up good work!