Aims: To validate the technical parameters of ALYATEC9s EEC with mite allergens. Method: The EEC is a 147 m3 chamber, located into the University Hospital of Strasbourg close to the intensive care unit. Its characteristics is that maximum parameters are controlled: temperature, relative humidity, ventilation rate, number and size particles, concentration of Der p 1 and VOC. Mite allergen extracts (ALK® and Stallergenes®) were nebulized through a nebulizer (SinapTec®, France).Der p1 concentrations were sampled using 5 glass fiber filters and measured with an ELISA Assay (Indoor biotechnology®, USA).Particles number and size were monitored online during nebulization, using 10 particles counters distributed inside the EEC. The cleaning process was also controlled and validated. Results: The reproducibility was excellent for the temperature, relative humidity and airflow. 3 concentrations of Der p1 were measured: 63, 76, 105 ng/m3 (n=45). For the 3 concentrations, the CV intrassay of Der p1 was 22±1.3%, interassay was less than 30%. For the particle size 0.5-5 and 5-10 µm, the CV interassay was 8 and 13%, respectively (n=19). The CV of the MMAD was 2.2% (n=10). No measurable airborne Der p1 was detected in the toilets and the medical supervision room (n=6) neither in the EEC 10 minutes after the end of exposure (n=9). No airborne VOC was measured in the EEC and the other rooms of the clinical unit (n=10). Conclusion: ALYATEC’s EEC is a 2nd generation chamber with high controlled and reproducible allergenic and non-allergenic exposure. The interassay CV obtained is better than in other EEC. Its close location to an intensive care unit makes it very safe especially for clinical research in asthmatic patients.