The Future of the Wire and Cable Industry is Halogen-Free
PVC has made up the bulk of the global Wire and Cable polymers market for quite a while now, representing nearly 70% of the volume used in 2018. The list of PVC’s favorable attributes makes it clear why it has been the dominant player in materials for low voltage wire and cable insulation, bedding, and jacketing.
PVC Advantages:
Low cost
Inherent flame retardancy
Very long service life (~25-40 years when used as insulation)
Easy processing due to it being a thermoplastic rather than thermoset polymer
Excellent physical properties (like resistance to corrosion, abrasion, and chemical attack)
While PVC has plenty of advantages in Wire and Cable applications, there are some notable downsides that shouldn’t be overlooked.
PVC Limitations:
Difficult to recycle
Off-gasing carcinogenic fumes when exposed to heat during processing and in service
High voltage cables need to handle continuous heat loads of 135 °C and higher
Halogen containing, failing to comply with the Wire and Cable Industry’s move toward Halogen-Free materials
Poor fit for high voltage applications since it starts to dehydrochlorinate at temperatures as low as 100 °C
I think we can all agree that off-gasing carcinogenic fumes is a good enough reason to think twice before selecting PVC as a material for a wire and cable application. Is that the only reason Wire and Cable wants to phase out halogen-containing materials? In a manner of speaking yes, since those carcinogenic fumes are produced when recycling PVC, and using PVC in a medium to high voltage application exposes it to sufficient heat to initiate dehydrochlorination. To elaborate a little, Wire and Cable is moving away from halogen containing materials due to:
Environmental Concerns
Halogenated materials release toxins into the air
Dehydrochlorination could result in HCl leaching into the water
Personnel Safety
Halogenated materials emit a thick toxic smoke that can become corrosive
The thick smoke contains dioxin and phthalates which are known carcinogens
Increased Risk of Equipment Damage
Toxic and corrosive smoke can damage equipment
Damaged equipment is expensive to repair or replace, and poses safety and productivity concerns
If Not PVC, What's An Environmentally Responsible Cable Manufacturer To Use?
Use of Crosslinked polyethylene (XLPE) as an insulation and jacketing material in medium and high voltage cables (voltage loads of 10-33 kV for medium, 50+ kV for high) is on the rise. As concerns about PVC continue to surface, we’re seeing manufacturers begin to replace PVC with XLPE as the insulating layer and jacketing materials for low voltage cables. The below table shows how XLPE stacks up against PVC:
.
PVC
XLPE
Halogen Free
x
✔
Low Smoke
x
✔
Flame Retardancy
Some inherent flame retardancy, however more FRs are usually added for W&C grades
Not inherently, FRs are usually added to jacket rather than XLPE insulation
Recyclable
Possible but difficult
✔
Conductor Temperature
70 °C
90 °C
Emergency Temperature
120 °C
140 °C
Short Circuit Temperature
160 °C
250 °C
Approved for High Voltage Use
x
✔
Approved for Low Voltage Use
✔
✔
Cost Range
$0.50/lb to $1.98/lb (for eco friendly PVC)
$1.10/lb to $1.59/lb
Service Life (Low Voltage)
<40 Years
25 Years
Polymer Type
Thermoplastic
Thermoset
Abrasion Resistance
✔
✔
Moisture Resistance
✔
100X PVC
Corrosion Resistance
✔
✔
Resistance to Chemical Attack
✔
✔
Insulation Resistance (mΩ Km-1)
20
1000
Shape Memory Characteristics
x
✔
Approved for Low Tension
✔
✔
Approved for High Tension
x
✔
No Added Plasticizers Needed for Flexibility
x
✔
We understand that there is no one-size-fits-all solution for materials selection. We're continuing to research alternate options that deliver all the benefits of halogen-free without compromising performance. So if you like what you see here, we have more good things to come!
In the meantime, if you're considering swapping out PVC for a more eco-friendly material and would like to speak with an expert, please click below.
