1 The ignition source unit should be located at the upwind direction of all release source units (the less the amount of release source that located at the upwind direction, the better the safety performance);
2 Keep ignition source unit away from release resource unit (the larger the distance between ignition source unit and release source unit, the better the safety performance);
3 As gas diffusion under wind direction is easier than under crosswind direction, keep upwind release source far away from the due upwind direction of ignition source (the smaller in Figure 1, the better the safety performance).