Barrier Armor Rating
A unit's Barrier Armor Rating (or BAR) is a statistic used to indicate how hardy a unit is on the battlefield. Armor types used on Combat units like BattleMechs, tanks, and AeroSpace Fighters are automaticly assumed to have a BAR of 10 because they've been constructed specifically for combat. Support units and civilian vehicles pressed into military service however, are typically not as well armored as their combat-oriented counterparts. The "armor" used by civilian and support vehicles is designed to protect them from everyday wear and tear rather than incoming missiles. The BAR provides a means to reflect the increased fragility of non-combat units in a combat area.
Basically any unit that is not built on an Armored Chassis hit by a weapon that inflicts more damage than its BAR will need to check for a critical hit, even if the weapon didn't damage internal structure. So a Silverfin coastal cutter (BAR 7) hit by a PPC blast will have to check to see if it substains a critical hit as the artificial lightning leaks through a small gap in the armor plating.
 IndustrialMech Armor
IndustrialMech armor was introduced in 2439 by the Terran Hegemony. Like their military cousins, IndustrialMechs mount armor in sheets weighing a full ton or half ton. Unlike BattleMechs, IndustrialMechs are not usually designed for combat, and may have been built with armor that has a Barrier Armor Rating of less than 10. IndustrialMechs can only mount a few armor types, none of them advanced.
- Heavy Industrial armor is functionally the same as BattleMech armor, with a stated BAR of 10.
- Industrial armor also has a BAR of 10, but only offers 67% points per ton that Heavy Industrial armor does. Industrial armor is very similar to Primitive Armor used by the first BattleMechs.
- Commercial armor offers 50% more protection per ton of weight, but only has a BAR of 5.