Volume flows of up to 100,000 cubic meters of air per hour and pressures of over 3,000 pascals are generated in the 2.5-meter air ducts by a 325-ton measuring section. The measurements, which are carried out under free-field conditions, do not cause any significant acoustic reflections. The basic level is far below 15 decibels at 15,000 cubic meters. The test rig procedures are certified and guarantee the highest quality standards: