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Low-smoke Halogen-free Flame Retardants

Parag Shah – Feb 19, 2021

TAGS:  Flame Retardants 

Low-smoke Halogen-free Flame RetardantsLow-smoke zero-halogen (LSZH or LSOH) is a material typically used for cable jacketing in the wire and cable industry. Low-smoke zero-halogen cable jacketing is composed of thermoplastic or thermoset compounds that emit limited smoke and no halogen when exposed to high sources of heat.

Low-smoke zero-halogen compounds are used in all kinds of industrial, energy, power, and data cable designs, including coaxial cables and fiber optic cables. As these compounds produce less acid gas than halogenated compounds during combustion, they can also be used in areas containing expensive or sensitive equipment, including:

  • Communication exchanges
  • Military applications
  • Power generation facilities
  • Offshore platforms
  • Oil & petrochemical installations, and many others.

Halogen-free compounds are used in both Europe and the United States, although they may not offer enough flame retardancy to meet fire protection codes for certain applications.

According to MarketsandMarkets, the halogen-free flame retardants market is projected to reach USD 6.2 billion by 2025 from USD 4.1 billion in 2020, growing at a CAGR of 8.60% during the forecast period.

Let’s understand the key factors, opportunities and challenges driving the low-smoke zero-halogen flame retardants market.


Key Factors Driving the Low Smoke Halogen-free Flame Retardant Market


Increasing Demand in Safety Cable Application in the Construction and Defense Industry to Drive the Market


Low-smoke halogen-free flame retardants (LS HFFR) are majorly used in the wire and cable industry for cable jacketing purposes. LSOH cable jacketing is custom compounded to produce minimal smoke and low toxicity when exposed to fire. Most network cables (CAT5, CAT6, etc.) are insulated with:


When in contact with fire, halogen-containing plastic releases hydrogen chloride, poisonous gas that forms hydrochloric acid when it comes in contact with H2O. Low-smoke zero-halogen cables do not produce this toxic combination of gas, acid, and smoke when exposed to flame. Since no harmful smokes are released, LS HFFR cables are often used where safety, along with performance and reliability, is critical. They are typically specified for use in densely populated, enclosed public spaces where flame-resistance, low smoke production, and reduced toxic gas emissions during combustion are critical.

The major applications for LS HFFR have confined spaces, such as residential and industrial buildings, with large amounts of cables in close proximity to people or sensitive electronic equipment. The military was one of the first adopters of LS HFFR standards. Mass transit and central office facilities are common applications for LS HFFR, and many telecommunication standards require low-smoke zero-halogen cables.

Low-smoke zero-halogen compounds also comply with the European Union’s Restriction of Hazardous Substances (RoHS) directive and similar North American safety and environmental standards.


Stringent Regulations Against Halogenated Flame Retardants Drive the LS HFFR Market


Most of the flame retardants are halogenated. These halogenated flame retardants along with other additives antimony trioxide and zinc-based substances are highly toxic in nature as they produced harmful gases/fumes on exposure to fire. In the event of a fire, the halogenated flame retardants also generate a lot of smoke which can reduce visibility and make evacuation difficult from premises or public vehicles.

Few brominated and chlorinated flame retardants have been phased out of use because of environmental and human health and safety concerns but some are still being used. With the increasing environmental consciousness and growing concern about safety, there is a need to switch to low-smoke halogen-free flame retardants that adhere to environmental regulations. In the construction and automotive industry, there are strict fire and smoke regulations all around the world.

In Europe, all electrical and electronic equipment in a train is approved according to EN 45545-2 of the European Railway Standard for Fire Safety. In a fire, low smoke density, without opacity, is a key figure and important in allowing passengers and staff in railway vehicles to escape and be rescued safely. In February 2020, the European Union imposed a ban on halogenated flame retardants in electronic displays and plastic enclosures. According to REACH and RoHS, electronic displays will not be allowed to contain brominated fire retardants or halogenated flame retardants.

Regulators like WEEE (Waste Electric and Electronic Equipment) and SVHC (Substances of Very High Concern), with inputs from some NGOs, have also helped to boost the demand for halogen-free flame retardants by setting certain standards (such as Underwriters Laboratories (UL), horizontal & vertical burn ratings, and glow wire testing).

In the US, many states have also banned halogenated flame retardants due to their toxic effects on the environment. This shift towards more environment-friendly alternatives will increase the demand for low-smoke halogen-free flame retardants, which, in turn, will drive market growth.

Stringent Government Rules Against Toxic Halogenated Flame Retardants to Drive Market Growth
Stringent Government Rules Against Toxic Halogenated Flame Retardants to Drive Market Growth


Opportunities in the Low-smoke Halogen-free Flame Retardants Market


Advanced Low-smoke Halogen-free Flame Retardants with Nano-fillers & Special Lubricants will be the New Trend


For low-smoke zero halogens, the cable jacket must be incorporated with a high percentage of filler material. This increase in filler material could make the jacket less chemical and water-resistant which reduces its mechanical and electrical properties than a non-LSZH counterpart. LSZH jackets experience cracking during installation, so special lubricants may be necessary to avoid damage. This is especially true in cold environments.

LSZH has limited flexibility which makes it unsuitable for robotic or continuous flex applications. As a result, LSZH cable is commonly chosen for applications where fire safety is more of a concern than the cable’s specific electrical and mechanical properties. Recent advancements in compound materials and processing have decreased some of these issues.

Nanofillers are being added to the thermoplastics. The main advantages are:

  • Lightweight
  • Decreased gas permeability
  • High modulus & strength
  • Increased solvent resistance, and
  • Increased thermal stability

These properties add benefit to the polymer matrix.

In 2014, NANOFRABS was developed under the European FP7 research project. Effective halogen-free flame retardant for ABS compound was prepared by incorporating 20 nano-fillers. These ABS compounds are widely used in the electrical appliances sector.

Currently, lubricants like zinc stearate, calcium stearate, magnesium stearate, and low-molecular-weight wax are preferred in small quantities (~0.2%- 0.5%) for the polyolefin/ polyethylene matrix to provide flexibility to the material.


High-performance Cable Variant in Hybrid and Fully Electric Vehicles will be in High Demand


In 2020, Toyota sold 3 million hybrid electric cars and had set a target of 5.5 million for the year 2030. Despite the challenging year, Volkswagen recorded a sale of 212,000 electric cars, which was more than that of the 2019 sales.

Due to the rise in the growth of hybrid and electric vehicles in the forecasted year, it is estimated that the demand for charging cables and polymers for interior and exterior will also increase. These charging cables will need to be flame retardant with zero-halogen and low-smoke emission. Therefore, the demand for low-smoke halogen-free flame retardants for cables and polymeric components will increase in the future.

Halogen-free Flame Retardants Market: Geographic Growth & Opportunites
Note: CAGRs are provided in terms of volume
Halogen-free Flame Retardants Market: Geographic Growth & Opportunites
(Source: Secondary Research, Expert Interviews, and MarketsandMarkets Analysis)


Key Challenges of the Low-smoke Halogen-free Flame Retardants Market


High Cost Could be a Major Challenge


The conventional cable is much cheaper than that of low-smoke halogen-free flame-retardant cables. Many countries in the Asia Pacific and the Middle East and Africa where regulations are not strict regarding LSZH jacketed cable will continue to use a cheap variety of conventional cables. Moreover, the current generation of LSZH cables has not yet established a proven history of long-term performance, which makes the customers opt for the traditional one.


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3 Comments on "Low-smoke Halogen-free Flame Retardants"
Paul H Jun 23, 2021
Great information included in this article. Amfine Chemical is a major supplier of halogen free flame retardants for Polypropylene, Polyethylene, TPO, TPE, TPU, Polycarbonate and Polycarbonate alloys. www.amfine.com or www.adeka.com
Koen S Feb 25, 2021
Valtris Specialty Chemicals produces phosphate ester plasticizers which assist in low smoke generation for flexible applications. www.valtris.com Koen Steen
Anil V Feb 22, 2021
Sir, We are the UPR ( Un saturated Polyester RFesin ) manufactutrers , need Low smoke Jalogen free Flame retardent. Thanks, Anil Verma

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