Another shot at the historical failure of fragmentation protection vest procurement

I am in the mood to take a shot at the poor protection of German troops in 1916 till about 1990 - again.

The German steel helmets of both World Wars had a thickness of about 1 - 1.1 mm only and provided useful protection against most fragments. It is generally recognized that the introduction of the steel helmet in 1916 greatly helped to reduce the lethality of fragmentation munitions.

The question remains; why no protection for the torso?
The scarcity of steel was hardly an adequate reason if you consider the weight efficiency. The temperature effects (hot in summer, cold in winter) were a question of design. The head was more vital than much of the torso and the heads were most exposed to fragments in trench warfare, but then again we introduced soft torso armour at about 3.5 kg weight after WW2! A semi-hard torso armour (such as a lorica segmentata or simply a vest with multiple small plates (as the extremely popular Korean War Doron plate vests) was even able to mitigate most of the stiffness problem.

How much would a protective vest have weighed down an infantryman? Let's check this:

A fragmentation protection vest of the Bundeswehr, finally introduced about two decades ago, has a protected area of about 50 dm^2 (square decimetres).

50 dm^2 = 50 * 100 cm^2 = 5000 cm^2
area of 5000 cm^2, thickness 0.11 cm = 550 cm^3

density of steel: approx. 8 kg/dm^3
1 dm^3 = 10 x 10 x 10 cm = 1,000 cm^3

550 cm^3 of steel weigh approx. 4.4 kg

A semi-hard torso armour would have had a smaller protected area (still better protection than none) than the soft torso armour, but even the same area could have been protected with only 4.4 kg weight up to steel helmet protection standard!

How much steel for the protection of nine million soldiers?

9 million x 4.4 kg = approx 40,000 metric tons of steel. That's a tiny fraction of a single year's steel production (less than 0.2% of the 1939 steel production, for example). A Chromium-Nickel steel alloy was used in the steel helmets, but even that should have been a minor problem in face of the tiny quantity of necessary steel. About a fourth of the troops needed such protection the most, so we could even reduce the steel consumption to a quarter of a fifth of a per cent of a single year's steel production!

A steel plate vest with a weight of about four kilogram was furthermore hardly an unacceptable weight addition. We added much more weight to an infantryman's equipment during the post-war years.

I still don't get why torso body armour had such a terribly slow comeback (especially in Germany). It looks like a terrible negligence of duty on part of procurement bureaucracy and military leadership to me.
Such an institutional failure needs to be remembered, we need to learn the correct lessons and we need to apply them.


P.S.: An earlier draft version of this was accidentally released previously. It had  faulty math.

edit: Some more figures.

The share of fragmentation munitions (mostly mortars and artillery) as causes for army KIA vary from war to war and battle to battle, but shares as high as 50-75% are common.

Fragmentation is a very inhomogeneous problem. Few fragments are large (and some will even penetrate an APC such as a M113) while many are small and lose speed and penetration power quickly.
The steel helmet was always a compromise between weight and effect, as would have been such steel plate vests.

"Soldat und Technik" V/1996 has an article from which I pulled the 50 dm^2 figure. It also offers a typical example for a classic HE frag shell fragmentation:
0.1-1.0 g: 77% of fragments
1.0-10.0 g: 21% of fragments
10.0 -1 40.0 g: 1% of fragments.

Another example:

The SuT article continues by stating that wartime experience about KIA by fragmentation is
50% by torso hits
40% by head hits
10% by other hits

Here is an extensive study about Korean War lessons in regard to wounds:


  1. First of all, thanks for another insightful article. Now, the criticism ;).

    Huh... I somehow find this hard to believe, given that today, protection against 7.62mm NATO and protection against artillery fragments is usually treated as the same, at least as far as vehicle armour is concerned.
    And since modern ammunition in 5.56mm or 7.62mm can easily penetrate multiples of 1.5mm of regular steel, I don't think that such a vest with steel inlays would offer sufficient protection against enemy fire or artillery fragments.
    It would likely protect the wearer against hand grenade fragments, but you can use much lighter and easier to wear basic kevlar vests to the same effect.

    I wonder where you get your numbers, but I assume that two other factors than the effectiveness of steel would have a greater impact:
    First, artillery during the first world war was largely "light" artillery, with medium calibers such as 75mm or 3'', which of course produce smaller shrapnel with a lower velocity.

    Second, and this I consider most important, a protective helmet has a very different ballistic profile (term?) than a vest. It has a rounded shape, which results in "thicker" effective armour (as with tanks) and can also deflect incoming projectiles a lot better, something which a "flat" vest inlay can not provide.

    Granted, your math makes sense, but I think the problem lies with the underlying assumtion:
    I still doubt the effectiveness of steel as compared to Kevlar and/or ceramic body armour.

    An afterthought: Besides, steel, when penetrated, can create more and nastier fragments itself than brittle ceramic.

  2. Steel and aluminum were the only real options in WW2, for the other stuff was either not invented yet or no real production capacity was at hand.

    I'm going to add (edit in) some figures that will highlight the relevance of such thin steel plates for protection.

  3. Have you read Bashford Dean's 'Helmets and Body Armour in Modern Warfare'(1920)?

    He covers the use of armour up until 1920, especially in the Great War. Essentially he argues that whilst body armour would help prevent wounds it is disliked by troops because (a) it is often clumsy and (b) it's weight.

    In particular he records soldiers feeling that wearing armour was just one item too many considering all the equipment already necessary in industrial warfare. He suggests that soldiers be provided with transport or that a light armour be designed only to protect the most vulnerable areas (such as major organs).

    The British actually adopted the latter idea in the second war and produced some millions of an armour designed to cover the vital organs. However it's name escapes me (I only remember that it was named after the Medical Board) and it was not issued to the troops.

  4. I don't know that book, but I've read other books and articles about the subject. A part of the early body armour problems especially until 1918 was that engineers attempted to make the armour bulletproof. It's much easier to make it proof against the vast majority of fragments instead.

    WW2 troops were usually not very much weighed down by their personal equipment, even the machine gunners. A transport vehicle (horse cart) per platoon was very usual, and soldiers carried thus usually less than 20 kg clothes and equipment (unless their leaders were dumb).

    Btw, the Japanese used body armour in WW2, too: