Operation of cable lines under fire conditions

摘要

Branched cable communications are carriers of fire load, they are tracks along which fire spreads in buildings and structures. Therefore, currently, fire safety of cables is one of the most important tasks of the cable industry. The spread of flames in vertical bunch wiring depends on the following factors: the amount of combustible material that is exposed to high temperatures, geometric shapes of cables and their mutual location when laying, the ignition temperature of gases emitted by cables, the volume of combustible gases emitted by cables at a certain elevated temperature, the room capacity and volume of air passing through the cable structure, cable devices. Analysis of regulatory documents revealed some key differences in the methodology of standards. It was found that the spread of fire is not only affected by the volume of laid cables, but also by their mutual placement in space. A direct correlation was found between the influence of the crosssection of the cable core and preservation of the cable line in case of fire. Parameters were determined for the preservation of serviceability under fire exposure in the case of bunch and in the case of single wiring. It has been determined that it is impossible to spread the results of fire tests in case of single wiring in accordance with GOST IEC 60331-21-2011 and in case of bunch wiring in accordance with GOST IEC 60332-3-22-2011 to the results of tests in accordance with GOST R 53316-2009 for the preservation of operability of cable lines. The parameters of fire resistance and operability of cable products under the influence of flame depending on the type of cables and the method of their installation have been determined.