Fire Testing

16. System circuit (functional) integrity in accordance with DIN 4102-12
Maintaining the function of electrical cable during the fire, defined as the concept of cable system is characterized by the German DIN 4102, part 12. DIN 4101-12 is a testing for functional integrity of entire electrical cable systems together with fastener components and shall be considered as the most rigorous,but on the other hand, as most closely simulating the real fire conditions,DIN 4102-12 defines the requirements and testing method for fire resistance of electric cable system required to maintain ircuit integrity. The standard defines testing for the functionality of so-called cable set, which consists of a roup set of power cables, telecommunications, data cables etc. to be fixed to the support structure consisting f channels, ladders, cable tray ,items to hang, handles, etc. Cables attached to this structure are powered y their work voltage. Functional integrity will be tested for short-circuit of insulation or discontinuity of any ire core.
DIN 4102-12 is a realistic fire-chamber testing with minimum dimensions 2 x 3 x 2.5 m. width/length/height). A complete cable installation is tested under realistic conditions. The effects of hermal expansion and mechanical load during a fire are taken into account. The temperature must follow the standard fire curve (ETK): At E 90, the system is tested for 90 minutes, with a flame emperatures reaching up to 1000°C during the test. The cable is installed in a furnace and mounted with cable trays and cable clips with guides. A voltage of 400 V AC is applied to the cable (or 110 V AC for telecommunications cables)
There are three categories of function maintenance as follows:
E30 - cable system function maintenance in case of fire for 30 minutes
E60 - cable system function maintenance in case of fire for 60 minutes
E90 - cable system function maintenance in case of fire for 90 minutes
The numbers in each case designate the period of time for which the integrity of the power circuit must be maintained.It is worth noting that duration of the cable operation under test is determined not only by design and selection of used cable materials, but also and often primarily, the construction and selection
of supporting structure materials, which is subject to deformation in high temperatures, and these   eformations in turn tighten the cables attached to the structure.