Flak Armour is a light and relatively primitive form of body armour used by the military forces of the Imperium of Man. It usually consists solely of a breastplate, shoulder pauldrons, knee plates, greaves and helmet and is most commonly used by the troops who serve in Imperial Guard and Planetary Defence Force regiments. It provides little protection against heavy weapons but resembles a modern day bulletproof vest in its protective ability. Its primary function is to deflect shrapnel or "flak". Flak Armour is the standard combat armour for the Imperial Guard and Planetary Defence Forces.
Flak Armour is manufactured from multiple layers of ablative and shock-absorbent materials that are primarily ceramic in origin and are intended to deflect and absorb the kinetic energy of a weapons strike or blow. The armour provides little protection from a direct weapons strike, though the protection it provides is sufficient to deflect damage from shrapnel, adjacent though not direct explosions and riccochets. The ablative properties of its ceramic construction are also excellent at heat dispersal, thus providing a small measure of protection from glancing hits with energy weapons like Lasguns and Plasma Guns. The materials commonly used in the construction of Flak Armour include Carbon-fibre, Plasfibre and Thermoplas strips, although a number of different materials can be integrated in non-standard suits of the armour intended for more specialised uses. Thermal-absorbent materials, applied to the armour's outer layer to reduce the thermal signature of the soldiers using it, provide an enhanced capability to remain invisible to enemy forces during night reconnaissance missions. Rarer still, Cameleoline fabric is incorporated into the outermost layer of some Imperial Guard Regiments' fatigues to enhance their ability to conceal themselves. Although Flak Armour is overall a relatively ineffective form of armour, it is incredibly cheap and easy to manufacture, requiring a very low technology base, and thus making it among the most popular forms of personal protection in the galaxy with a variety of the starfaring races.
Flak Armour is most often used by the Imperial Guard, Imperial Planetary Defence Forces and the armsmen of the Imperial Navy, but has also been used by other intelligent races' military forces, including the Orks and the nearly-extinct Squats. Due to the sheer diversity of military formations that make use of Flak Armour, there is no standardised format for it, either in the Imperial Guard or other services. Many Imperial Guard Regiments customise their armour as a result of their own specific cultural and environmental needs. For instance, the Cadian Regiments of the Guard use the most common pattern of Flak Armour, including helmets, breastplates and shoulder paldrons as illustrated above, while the Valhallan Ice Warriors prefer to incorporate their Flak Armour in the form of an overcoat that provides protection from the frigid conditions that prevail on their ice-covered homeworld. However, in the end, all the different forms of Flak Armour serve the same purpose and provide the same level of protection, differing only by the environmental demands of the battlefield and the traditions of the unit deployed to fight in them.
- Warhammer 40,000: Wargear (2nd Edition)
- Warhammer 40,000: Wargear (4th Edition)