Unreasonable layout could increase the probability of serious accident, such as fire and explosion. The main concern here
is how to arrange the position of ignition source unit relative to flammable gas release source unit. The flammable gas
release source unit means facility or position which could release flammable gas, and the ignition source unit means facility
that contains any kinds of ignition energy, such as fired heater, non-explosion proof electric apparatus and so on.
Reasonable layout can consider the process requirement and environmental impact factors, and arrange reasonable positions
for all release source units and ignition source units. The ignition sources are always arranged at the position with low
coverage risk of flammable gas, so as to reduce the probability of gas explosion.