Material Properties
Insulation & Sheath Material Properties to Offshore and Marine cables

EP - rubber (EPDM)

EPDM is a hydrocarbon rubber that combines electrical performance suitable for fire resistant offshore cables with mechanical toughness and resistance to ozone, UV light and heat. It's wet electrical properties are unique. It is very flexile at high and low temperatures ( -55°C to 150°C). It has good insulation resistance and dielectric strength, as well as excellent abrasion resistance. EPDM also has better cut-through resistance than Silicone rubber, which it replaces in some applications. EPDM exhibits satisfactory compatibility with fireproof hydraulic fluids, ketones, hot and cold water, and alkalis, and unsatisfactory compatibility with most oils, gasoline, kerosene, aromatic and aliphatic hydrocarbons, halogenated solvents, and concentrated acids.

Flame retardant halogen-free termoset compound (EVA)

EVA, ethylene vinyl acetate, is a multi-functional elastomer, which resists the combined deteriorating influences of heat, oil and weather. (In accordance with IEC 60092-359 type SHF2). For offshore applications, EVA can be
compounded to produce high quality cable sheathing with low smoke and flame propagation, and with no emission of halogenous acids.

It is a polymer that approaches elastomeric materials in softness and flexibility, yet can be processed like other thermoplastics. The material has good clarity and gloss, barrier properties, low-temperature toughness, stress-crack resistance, hot-melt adhesive water proof properties, and resistance to UV radiation. EVA has little or no odor and is competitive with rubber and vinyl products in many electrical applications.

Low smoke , Flame retardant , Halogen-free and Thermoplastic compounds(HFFR)

When PVC is not acceptable due to the problems chlorine (halogen) containing materials present in the event of a fire HFFR must be used. (In accordance with IEC 60092-359 type SHF1). HFFR materials will not propagate a fire along a cable run, drip or give off black smoke. No acid gases will be released during a fire that can corrode and damage expensive equipment.

Physical and chemical properties

	Enhanced oil resistant EVA (SHF2)	NITRILE/PVC	PVC	HFFR (SHF1)
Mechanical properties	G - E	E	E	F - G
Weathering (OF -OG )	O	E	O	E - G
Heat resistance	E	G	F - G	E
Low temperature	G	G	F	G
Hydrocarbons general	G - E	E	F	NR
Hydrocarbons high aromatic (MUD)	G - E	E	P	NR
Sea-water	G	E	E	G
Fire resistant	E	G	E	E
Oxygen Index	E(35)	G(28)	E(32)	E(35)
Smoke generation	O	F	P	O
Halogens	No	CI	CI	No

 

NR = Not recommended; P = Poor; F= Fair; G = Good; E = Excellent; O = Outstanding

Difference between SHF1 and SHF2

	SHF1	SHF2
Type of material	Halogen-free Thermoplastic	Halogen-free Elastomeric or thermosetting material
Some main characteristics
Mechanical characteristics after immersion in hot oil (IEC 60811-2-1, clause 10)* * If oil resistance is required for a halogen-free compound, SHF 2 compound is recommended.	No requirements	100 °C for 24 hours: ±40% maximum variation in tensile strength: ±40% maximum variation in elongationat break
Hot set test (IEC 60811-2-1, clause 9)	No requirements	200 °C, 15 min time under load with 20 (N/mm²) mechanical stress: 175% Maximum elongation under load 25% Maximum permanent elongation after cooling
Pressure test at high temperature IEC 60811-3-1, subclause 8.2)	80 °C, 4-6 min under load depending on cable diameter: 50% Maximum permissible deformation	No requirements
Heat shock test (IEC 60811-3-1, subclause 9.2)	150 °C) 1h duration:	No requirements
Ozone resistance test IEC 60811-2-1, clause 8 (Alternative test method may be used in some countries for legal reasons)	No requirements	25 ± 2°C for 24 h: Max 0,025 to 0,030 % ozone concentration (in volume)