Wanderlust World Wanderlust World The riser cable test is most commonly used as a flammability test for communication or data cables, but it can also be used to test electrical cables in public transportation vehicles. (See Reference 1, 2)
Riser cables must pass the ANSI/UL 1666 cable test apparatus. The cables are vertically tested in a 4 foot-by-8 foot-by-19.75 foot area that is divided into two compartments, stacked vertically. A gas flame of 155kW is lit underneath the first compartment next to the cables and remains on for 30 minutes.
Riser cables pass the UL 1666 if there is no presence of "flame" at the top of the bottom compartment. If the cable spreads the flame from the bottom of the floor to the second story, it results in an automatic fail. This test is more severe than the standard cable tray test -- a test that measures flame spread of cables placed into trays situated either vertically or horizontally, but does not measure the visibility level of smoke obscuration (the degree to which smoke obscures observation during a fire). Additionally, char length (i.e. amount of damage caused by the flames to the cables), mass loss (i.e. amount of mass of the surrounding and affected area lost due to damage during the fire), and heat release (i.e. the flame's temperature at its peak) are not tested.
For aircraft, riser cables have been experimentally tested under the 60 degree Bunsen burner flammability test, intermediate-scale vertical test, and the intermediate-scale cabin attic flammability test. One of the cable experiments targeted the adequacy of the Federal Aviation Administration's test requirements under severe, or high flame, ignition source conditions. (See Reference 3) Cahill's 2006 study found that while the Riser cable used passed the 60 degree flammability study, it failed the intermediate-scale testings due to the large-scale spread of flames (See Reference 4).