Doors separate either rooms with equal temperatures and humidities or rooms with differential climates.
Climatic distinctions lead to swelling and shrinking of the components and thus deformation of the door.
In order to meet not only the functional demands in respect of sound insulation and fire protection but also the optical requirements deformation and distortion of the door may not exceed certain values.
The classification of the doors is defined by DIN EN 1530 / EN 12219.

• Test in constant climate:
  The doors are exposed allround to certain climates, e.g. for testing their performance under extreme conditions.
• Test in differential climate:
  After conditioning in constant atmosphere the doors separate different climates. Bowing and distortion are recorded over a period of 28 days.