If the general needs for ventilation are the same ones, for the quartering and the blocks of combat (to evacuate the polluted air and to be able to breathe normally), an important parameter however carries it in the vicinity of the weapons: during their shootings they produce a great quantity of pollutant gases, particularly concentrated in their gun and the empty cases of the consumed ammunition. The air of the station of shooting very quickly becomes noxious.
In fortification CORF there exist two types of blocks of combat: those with turret and those without turret (casemate), and ventilation is not treated same manner in these two types of blocks.
In this document we will be interested, exclusively, with the ventilation of a block with casemate.
Insulation
Insulation of the block
Diagram (outline) of the ventilation of a block with active casemate (of combat).
The first precaution to be taken consists to insulate the block, by a tight hopper, and to feed it by fresh air drawn from quartering. This air, under light pressure and in sufficient quantity, drives out pollutant gases outside the fortification. When the hopper remains open (most of the time), this device is not used. It is the case apart from the periods of alarm. No matter what…
Helps with the ventilation of quartering
… On September 4, 1939, just after the declaration of war of France in Germany, Hackenberg supplemented are crew (effective: 33 officers, 131 warrant officers, 846 troops; commander: Commander Ebrard) and starts to function under the normal conditions envisaged by the Genius. Several difficulties arise then of which that of the normal replacement of the air in quartering. During the meeting of “commission of work”, the Commander Ebrard dictates the following order then:
Point XII. Interior service… The chiefs of blocks will ventilate all at the same time 6:00 with 8:00, hoppers closed, all the open openings of blocks and in “normal” mode to go up the air of the galleries.
As it is noted, the device of ventilation of the blocks can be used to quickly renew all the air of quartering.
Bambesch (SF Faulquemont). Hopper insulating block 2.
Holy Agnes (SFAM). Side active block (of combat), behind the hopper insulating block 2, a powerful ventilator propels the fresh air of quartering.
Holy Agnes (SFAM). Pure air intake (vertical) in front of the hopper, side quartering.
Pressurization
Pressurization of the block of combat
Diagram (outline) of the ventilation of a block with active casemate.
At the price of a overcost of construction, one can, at the same time, avoid the penetration of possible poison gases, to protect themselves from an attack by flame thrower and grenades, and to eliminate pollutant gases from propulsion of the drawn ammunition. It is enough to make tight the crenels!
This total insulation of the block makes it possible, indeed, to pressurize it slightly, with the air ventilation system. Even if the openings are not completely hermetic the interior air is opposed then to very entered inopportune and, moreover, with each opening of cylinder heads, the air of the block is engulfed in the light of the gun and drives out the toxic residues of the drawn ammunition.
Overpressure envisaged is of “water 3mm” in the blocks of infantry and “water 7mm” in the blocks of artillery. Pressure gauges make it possible to control this overpressure and of the panels recall it (see below in a casemate for JM).
Caution. Twinning of machine-guns. When the interior overpressure of the room goes down below 1mm water: to take the security measures against pollutant gases emitted by the parts (carbon monoxide).
Museum of Fermont (SF Crusnes). At the end of this trumelage (2 machine-guns and a gun of 25mm) one can see the kneecap allowing the pointing of the weapon while preserving seals his crenel.
Room of neutralization
Room of neutralization
Diagram (outline) of the ventilation of a block of combat.
The overcost of construction, to pressurize the block of combat, is not limited to the price of the tight crenels. Indeed, when the weapons draw, especially when it acts of artillery material, requirements in fresh air are so important that of quartering would not be enough there. Moreover, to pump in quartering, it is to put it in depression and to support its pollution by poison gas. As regards ventilation it is essential thus that the block is autonomous and has its own room of ventilation. And which says ventilation says also neutralization (by filters) possible poison gases.
Saint-Agnes (SFAM). B2 being strongly armed (1.JM, 2.75,2.135,2.81), its room of neutralization is imposing (here with the standardized colors of origin).
Schoenenbourg (SF Haguenau). Certain rooms of neutralization have an air intake in frontage of block, others have one by armor-plated mushroom of them (foreground of the photograph). It is the case in B2 TM of Schoenenbourg.
Worn casings
To become worn casings
The casings (cases) of the ammunition of infantry, of small gauge (for FM, JM, AC25, AC37, AC47, etc), are not reusable, contrary to those of the artillery ammunition. The first are thus eliminated from the fortification, by a sheath crossing the concrete, whereas the seconds are stored in a “room with casings” for a later re-use.
Ammunition of infantry
Schoenenbourg (SF Haguenau). Under this JM of Block 7 one sees very well the sheath of evacuation of the casings leading these last from their exit of cylinder head to a sheath fixes crossing the concrete.
Lower St Véran (SFAM). The sheath of evacuation of the JM (B2) emerges on the level of the crenel, under its axis of shooting.
Artillery ammunition
Diagram (outline) of the ventilation of a block with active casemate.
The casings, ejected cylinder head, come to strike a splash plate then fall into a funnel which leads them on a toboggan from where they slip to the room of recovery (room with casings). The whole is tight, to avoid the contamination of the block by the toxic residues contained in the casings.
Holy-Agnes (SFAM). The splash plate is quite visible, with the back from this 75/31 of B2. This splash plate is fixed at a mobile system; interdependent of the gun it follows it during its movements of pointing in direction.
Furnace-with-lime (SF of the Vosges). Toboggan of B2, with doors tight installed at various levels, for the case or from the casings would come to be wedged during their descent.
Panel of access to the “room with casings” of B2.
Ventilation of the casings
Ventilation of the room with casings
When the shootings are finished, the ventilator “fresh air” makes it possible to put in overpressure the “room casings” because the latter and its toboggan are hermetically closed, even on the level of the gun. Indeed, on the level of the funnel, behind the gun, a non-return valve with beam is closed again automatically after each passage of casing.
The “room with casings” being in overpressure, a simple sheath of evacuation, without ventilator, eliminates pollutant gases then (CO), in about fifteen minutes.
Holy Agnes (SFAM). Door seals room with casings of B2. One can see the two sheaths: air flow pure (red) and departure of foul air (yellow) which make it possible to cleanse the casings before recovery.
Consequently, one can carry out a final diagram of the ventilation of a block of combat with active casemate.
1940. Ventilation of fortifications CORF
Diagram (outline) of the ventilation of a block with active casemate (of combat).