PVC Vs. PE vs. EPR: A Comprehensive Review of Cable Insulation Performance in Fire and Service Conditions

Abstract

This review evaluates the fire dynamics, operational limits, and environmental profiles of PVC, PE, and EPR cable insulations, synthesising data from cone calorimetry (ISO 5660), vertical flame tests (IEC 60332), and thermogravimetric analysis. PVC achieves the lowest peak heat release rate (PHRR: 200–400 kW/m²) and an LOI of 20–25%, primarily via endothermic dehydrochlorination and gas-phase radical scavenging by HCl [1][7][8]. This fire-retardant advantage, however, incurs the highest smoke density (1,000–1,500 m²/kg) and corrosive HCl emissions, with a continuous service ceiling of 90°C [5][7]. PE exhibits superior dielectric properties (?r ? 2.3) but fails critically in fire scenarios: PHRR exceeds 1,000 kW/m², heat of combustion reaches 43–46 MJ/kg, flame spread rates of 5–15 mm/s, and char yield below 5%, rendering it inherently flammable with no protective residue [9][10]. EPR provides the best thermal endurance (service up to 105°C, peak 150°C) and balanced fire performance—intermediate PHRR (400–700 kW/m²), char yield of 10–30% (enhanced by inorganic fillers), and lowest smoke production (400–800 m²/kg)—without halogenated byproducts [2][4][6]. Material selection remains inherently application-specific: PVC for cost-driven, low-fire-risk installations; PE only where electrical performance is paramount, and fire mitigation is externally enforced; EPR for high-temperature or safety-critical environments [5][6][9]. The review further identifies emerging technical pathways—AI-driven early-warning systems, nanofillers, hybrid flame retardants, and halogen-free formulations—as key to decoupling fire resistance from environmental toxicity in next-generation cable systems [12].

Introduction

The text discusses the fire risks of electrical cables, the importance of cable insulation, different insulation materials, their fire behaviour, and the IEC 60332 vertical cable flame test.

Electrical cables are essential in residential, commercial, industrial, and transportation systems, but they can become major sources of fire due to insulation ageing, overloading, short circuits, arcing, moisture, chemicals, UV exposure, and mechanical damage. Cable fires are especially dangerous in places such as power plants, nuclear facilities, chemical industries, and underground utility tunnels, where they can cause equipment damage, power failures, toxic emissions, explosions, and significant economic losses.

Cable fires generally begin through overheating, partial discharge, or external heat sources. After ignition, flames spread through convection, radiation, and heat conduction along the cable. Vertical cables are particularly hazardous because the chimney effect can make flame spread 10–30 times faster than in horizontal cables. The combustion of insulation can also release toxic gases such as hydrogen chloride and carbon monoxide.

Major Cable Insulation Materials

• PVC (Polyvinyl Chloride):
  PVC is widely used because it is inexpensive, flexible, chemically resistant, and has good electrical properties. Its relatively low heat release and self-extinguishing tendency provide some fire resistance. However, burning PVC releases corrosive and toxic HCl gas and produces large amounts of smoke. It is commonly used in building wiring, appliance cords, control cables, automotive wiring, and industrial cables.

• PE (Polyethylene):
  PE provides excellent electrical insulation, moisture resistance, chemical resistance, and mechanical performance. However, it is highly flammable, has a low limiting oxygen index, produces very high heat release, and forms little protective char. It can therefore result in rapid flame spread and intense fires. It is widely used in power, telecommunications, data, and speciality cables.

• EPR (Ethylene Propylene Rubber):
  EPR provides excellent thermal stability, flexibility, and durability, making it suitable for demanding environments. Its fire performance is better than ordinary PE but generally depends on fillers and additives. It produces moderate heat and smoke and can form protective char. EPR is used in medium- and high-voltage, mining, submarine, offshore, nuclear, railway, and industrial cables.

Fire Behaviour Comparison

The three materials show significant differences:

PE presents the highest fire hazard because of its high heat release and negligible char formation. PVC has lower heat release but creates significant toxic and corrosive smoke. EPR provides a balanced combination of thermal, mechanical, electrical, and fire performance, particularly when suitable fillers are used.

Vertical Cable Flame Test

The vertical cable flame test evaluates how quickly flames propagate along vertically installed cables. It is important because vertical arrangements can significantly accelerate fire spread through the chimney effect.

The IEC 60332 series provides international standards for cable flame-propagation testing, including tests for single insulated wires/cables, bunched cables, and cables installed in ducts. The test helps determine whether cables meet required fire-safety criteria and are suitable for particular applications.

Conclusion

This comprehensive review examined the comparative fire behaviour, operational integrity, and environmental impact of the three principal polymeric cable insulation materials: polyvinyl chloride (PVC), polyethylene (PE), and ethylene propylene rubber (EPR) [1][2][5][6][7][9][10]. PVC exhibits moderate fire performance with inherent flame retardancy from chlorine content [1][7][8]. The dehydrochlorination reaction absorbs heat and produces HCl, inhibiting gas-phase combustion, providing the lowest heat release rate (200–400 kW/m² peak HRR) and best intrinsic fire resistance [1][7][8]. However, this comes at the cost of high smoke production (1,000–1,500 m²/kg) and toxic HCl emissions [1][7]. Environmental impact is substantial from corrosive acid gases and phthalate plasticizers [5][7]. Continuous service temperature limited to 70–90°C [5][7]. PE provides outstanding electrical properties with the lowest dielectric constant and loss factor, ideal for high-frequency and high-voltage applications [1][9][10]. However, fire behaviour is the poorest, with the highest heat release rate (1,000–1,500 kW/m² peak HRR), most rapid flame spread, and negligible char formation [1][10]. High heat of combustion (43–46 MJ/kg) and absence of inherent flame retardancy create significant fire hazards [1][10][11]. Black soot smoke with high optical density and substantial CO emissions are significant concerns [10][11]. Service temperature limited to 70–90°C [9][10]. EPR provides the best thermal stability (continuous service 90–105°C, peak 130–150°C) and intermediate fire performance (peak HRR 400–700 kW/m² at 50 kW/m² heat flux) [1][2][4][6]. Filler content contributes to moderate char formation (10–30%), providing barrier protection [2][6]. Smoke production (400–800 m²/kg) is lower than PVC but comparable to PE [1][6]. Environmental impact is moderate with no halogen emissions [6]. Excellent flexibility and mechanical properties make EPR suitable for demanding applications [2][4][6].

References

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Copyright

Copyright © 2026 Harshit Ray, Tejsingh Patle, Dinesh Matangi, Dhiraj Sharma, Nathan Khobragade, Rudrasinh Vaghela. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.