The German standard DIN 4102-12 specifies the entire system of cable trays, accessories and cables tested in an oven that is at least 3 meters long. The cable tray system in the oven heated up at temperatures of 1000°C for a period of 30, 60 or 90 minutes, the fire resistance grade woule be E30, E60 or E90 respectively.
The wire mesh cable tray system picture taken after 90 minutes at temperatures of 1000°C.
The E90 fire resistance grade ensure the electrical system such as emergency lighting, ventilators, emergency exit, fire alarm, etc. can remain working properly and resist long enough to provide assistance in the event of a fire. What's more the completely open design of wire mesh cable trays would make sure smoke detectors and fire sprinklers would not be blocked.