Breathable curtain wall
Curtain walls

The term "breathable window", "breathable facade" or "breathable curtain wall" is used to describe the air space between the glazings. From the outside :

• single glazing ;

• a breathable air space ;

• double glazing.

The space is made breathable with several ventilation holes at the bottom, to which insect and dust screens are fitted. An electric blind (canvas or Venetian) is added to this breathable space.

Although the rules for this technique are set out in the latest DTU 33.1, it is still subject to a test at CSTB as shown in figure 5. The aim of the test is to determine the minimum cross-sections of the breathing grilles to avoid fogging.