2019-4_Pages_62-70

I.R. Khasanov, A.A. Varlamkin

FIRE RESISTANCE LIMITS OF CABLE PENETRATIONS UNDER THE COMBINED EFFECT OF FIRE AND CURRENT LOAD

Abstract. The article considers the questions of influence of current load on fire resistance of cable penetrations in case of fire. Three most common types of penetrations were selected to study the effect of the design of cable penetrations on the heating processes of the cable. On the basis of experimental studies there are determined the values of the power cut-off time by circuit breakers in case of a short circuit in standard cable products with copper conductors. As a result of numerical simulation of heat transfer processes in cable penetrations under the combined effect of fire and long-term permissible load current there are obtained new data on the temperature dynamics in the elements of cable penetrations. It is established that under the combined effect of fire and long-term permissible load current, fire resistance limits of the considered cable penetrations are 25% of the standard values. Studies have shown that when developing the estimation methods for fire resistance limits of cable penetrations it is necessary to take into account the combined effects of fire and long-term permissible load current, as well as thermal characteristics of cable penetration. It is revealed that the most possible place of cable damage (both at the load current flowing and as a result of the joint impact of fire and load current) is the center of the cable penetration at the distance of 5–25 mm from the edge of the sealing material.

Keywords: cable penetrations, cables, permissible load current, fire resistance, fire resistance limit

References

1. Smelkov G.I., Pekhotikov V.A., Ryabikov A.I. Problems of fire safety of cable flows. Kabeli i provoda – Cables and wires, 2005, no. 2, pp. 8–14. (In Russian).
2. Bartnikas R., Srivastava Е. Characteristics of Cable Materials in Power and Communication Cables. NewYork, IEEE Press, 2000, 345 p.
3. Grigor'eva M.M., Kuznetsov G.V., Strizhak P.A. Assessment of the fire hazard of electric overload modes of cable lines. Pozharovzryvobezopasnost – Fire explosion safety, 2010, no. 9, pp. 9–13. (In Russian).
4. Khasanov I.R., Varlamkin A.A. Influence of cable penetrations design on their fire hazard during operation. Bezopasnost truda v promyshlennost – Occupational Safety in Industry, 2019, no. 3, pp. 46–51. (In Russian).
5. GOST R 53310–2009. Prokhodki kabel'nye, vvody germetichnye i prokhody shinoprovodov. Trebovaniya pozharnoi bezopasnosti. Metody ispytanii na ognestoikost' [State Standart R 53310–2009. Through penetration for cables, hermetic inputs and through penetration of electric current types. Requirements of fire safety. Fire resistance test methods]. Moscow, Standartinform Publ., 2009, 7 р. (In Russian).
6. GOST 31996–2012. Ispytaniya elektricheskikh i opticheskikh kabelei v usloviyakh vozdeistviya plameni. Sokhranenie rabotosposobnosti. Chast' 21. Provedenie ispytanii i trebovaniya k nim. Kabeli na nominal'noe napryazhenie do 0,6/1,0 kV vklyuchitel'no [State Standart GOST 31996–2012. Tests for electric and optical fibre cables under fire conditions. Circuit integrity. Part 21. Procedures and requirements. cables of rated voltage up to and including 0,6/1,0 kV]. Moscow, Standartinform Publ., 2014, 8 p. (In Russian).
7. GOST 31996–2012. Kabeli silovye s plastmassovoi izolyatsiei na nominal'noe napryazhenie 0,66; 1 i 3 kV. Obshchie tekhnicheskie usloviya [State Standart GOST 31996–2012. Power cables with plastic insulation for rated voltages of 0,66; 1 and 3 kV. General specifications]. Moscow, Standartinform Publ., 2013, 34 p. (In Russian).
8. Khasanov I.R., Varlamkin A.A. Experimental methods for determining the fire resistance of cable penetrations in a fire taking into account the influence of load currents. Problems of forecasting emergency situations. Sbornik materialov XVII nauchno-prakticheskoy konferentsii [Proceedings of the 17th Scientific-Practical Conference]. Moscow, FKU Center "Antistikhia" EMERCOM of Russia, 2018, pp. 77–78. (In Russian).
9. Segerlind L. Primenenie metoda konechnykh elementov [Application of the finite element method]. Moscow, Mir Publ., 1979, 392 p. (In Russian).
10. The Salome-Meca and Code_Aster Home Page. Available at: http://www.code-aster.org/
11. The Salome Page. Available at: http://www.salome-platform.org/
12. Matyukhin S.I., Makulevsky G.R., Deev O.V. Modern software for modeling in electronics. Informatsionnye sistemy i tekhnologii – Information systems and technologies, 2014, no. 2 (82), pp. 58–71. (In Russian).
13. GOST R MEK 60287-1-1–2009. Kabeli elektricheskie. Raschet nominal'noi tokovoi nagruzki. Chast' 1-1. Uravneniya dlya rascheta nominal'noi tokovoi nagruzki (100%-nyi koeffitsient nagruzki) i raschet poter'. Obshchie polozheniya [State Standart GOST R IEC 60287-1-1-2009. Electric cables. Calculation of the current rating. Part 1-1. Current rating equations (100% load factor) and calculation of losses. General]. Moscow, Standartinform Publ., 2009, 20 p. (In Russian).
14. GOST 30247.0–94. Konstruktsii stroitel'nye. Metody ispytanii na ognestoikost'. Obshchie trebovaniya [Elements of building constructions. Fire-resistance test methods. General requirements]. Moscow, Standartinform Publ., 1994, 19 p. (In Russian).

Received  April 17, 2019

Authors:

Irek R. Khasanov — Doctor of Technical Sciences, Main Researcher. Phone: (495) 521-89-38. E-mail: irhas@rambler.ru;

Andrey A. Varlamkin – Head of Sector. Phone: (495) 521-21-31. E-mail: A.varlamkin@yandex.ru

All-Russian Research Institute for Fire Protection (VNIIPO), Ministry of the Russian Federation for Civil Defense, Emergencies and Elimination of Consequences of Natural Disasters (EMERCOM of Russia), Balashikha, Moscow region, Russia.