EMMA device

Fig. 10.129. The EMMA device in the field at Heraeus DSET Laboratory Inc.

EMMA devices are successfully used by many manufacturers, particularly in the surface-coating industry, who wish to evaluate rapidly the durability of their products outdoors. However, these devices are also used in the study of accelerated weathering of almost all polymeric materials and plastics. One of the largest testing stations in the world is Heraeus DSET Laboratory Inc. (45601N, 47 Ave., Phoenix, AZ 85027-7042, USA) it employs hundreds of EMMA and EMMAQUA devices. 

Accelerated outdoor weathering devices EMMA Test Method (ASTM G90-91)... 

Fig. 11.5 ORWET degradation on the UAWS—by days (UA—ultra-accelerated device FL RT—Florida real time AZ RT—Arizona real time EMMA—ASTM G90 device)...

These devices automatically follow the path of the sun in the sky. EMMA contains 10 highly polished aluminium mirrors precisely placed on a rack which is turned and tilted at computed angles in order to focus the sunlight onto the surface of the sample (3 cm x 13 cm) (Figs 10.128, 10.129). The mirrors reflect 70-78% of the UV radiation of sunlight and consequently the intensity of irradiation is about 8-10 times higher than in the case of a fixed... 

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