The idea for this came about because Area Effect rules in Mobile Frame Zero are problematic. Due to, possibly, dealing with multiple targets getting activated at the same time. This rule was an attempt to duplicate the effect without the inherent issues. It works thusly. You declare a piece of terrain as Explosive. It doesn't have to be Cover. Then you decide how much Damage it will take before it explodes. We usually go with 1 Hit because we like seeing things go "BOOM". This is the Damage Threshold. Then you determine how far away in ruler Units things will be effected. This is the Blast Zone. When the item in question is hit and destroyed you roll a die to determine how far away in Ruler Units everything is pushed. We generally use 1d6. This is the Blast Radius. And by everything I mean Frames, Stations, and Cover/Terrain. If a Frame or Station is pushed off the Battlefield in this manner it is Out Of Play and the person controlling it loses those points.
So simply, Declare item, set Damage Threshold, set Blast Zone, roll Blast Radius, determine effects. You can see there's a lot of ways to tweak this rule and I look forward to hearing how you use it.