Experimental Study on Delaying the Failure Time of In-Service Cables in Trays by Using Fire-Retardant Coatings

Feng Jiang,Jianbo Yan,Dong Liang,Jianyong Liu,Wei Yuan,Lin Wang

doi:10.3390/app11062521

Abstract

Improving the fire resistance of the key cables connected to firefighting and safety equipment is of great importance. Based on the engineering practice of an oil storage company, this study proposes a modification scheme that entails spraying fire-retardant coatings on the outer surface of a cable tray to delay the failure times of the cables in the tray. To verify the effect, 12 specimens were processed using five kinds of fire-retardant coatings and two kinds of fire-resistant cotton to coat the cable tray. The specimens were installed in the vertical fire resistance test furnace. For the ISO 834 standard fire condition, a fire resistance test was carried out on the specimens. The data for the surface temperature and the insulation resistance of the cables in trays were collected, and the fireproof effect was analyzed. The results showed that compared with the control group, the failure time of the cable could be delayed by 1.57–14.86 times, and the thicker the fire-retardant coatings were, the better the fireproof effect was. In general, the fire protection effect of the fire-retardant coating was better than that of the fire-resistant cotton.

Highlights

As an electrical product for transmitting electricity, information, and electromagnetic energy, cables have been widely used in various areas of the modern economy, which is the basic guarantee for the normal operation of the modern economy and society.As the insulation and the sheathing of cables are generally made of plastic or rubber and other flammable materials, they can be damaged under high temperature conditions [1]
The difference between the three temperature curves in the tray and the furnace temperature curve in Figure 6e was the largest, which indicated that the fire protection effect of the specimen coated with 40 mm non-intumescent fire-retardant coating for steel structure (NFC) in case 8 was the best
Taking the insulation resistance drop by two orders of magnitude as the cable failure criterion, it was concluded that the failure time of the cable could be delayed to 1.57 to 14.86 times the blank control

Summary

Introduction

As an electrical product for transmitting electricity, information, and electromagnetic energy, cables have been widely used in various areas of the modern economy, which is the basic guarantee for the normal operation of the modern economy and society.As the insulation and the sheathing of cables are generally made of plastic or rubber and other flammable materials, they can be damaged under high temperature conditions [1]. The fire accident in the Dalian’s oil depot on 16 July 2010 caused damage to the power supply lines and distribution rooms at the initial stage of the fire. All the low-voltage power supply was interrupted, so all of the oil tank emergency shut-off valves could not be electrically shut off. The manual operation of the electric valve was slow and dangerous, which caused great difficulties in firefighting [2,3]. In the case of fire, some key cables connected to the firefighting and safety equipment became the weak point of the emergency system. It is of great significance to improve the fire resistance of such key cables [4,5]

Methods

Results

Conclusion