The challenge:
A leading manufacturer of medium-voltage cables insulated with cross-linked polyethylene (XLPE) faced a growing challenge: keeping pace with increasingly strict fire safety regulations for cables used in public buildings, transportation systems, and other critical infrastructure. Traditional insulation systems, based on halogenated flame retardants, offered effective flame resistance but released dense, toxic, and corrosive smoke when exposed to fire—posing risks to health, visibility, and nearby equipment. This project focused on a 6600 V-class XLPE cable, commonly used in demanding environments where both electrical performance and fire-safe construction are essential. The goal was to develop a solution that delivers low smoke and zero halogen (LSZH) performance, while preserving the cable’s mechanical strength, dielectric integrity, and efficient manufacturability.
The Solution
After extensive research, the company chose to replace its halogenated flame retardants with KISUMA™ 5A, a high-purity, ultrafine magnesium hydroxide. Unlike the previous material, KISUMA™ 5A is a non-toxic, inorganic flame retardant and smoke suppressant. Its mechanism is simple and effective: when exposed to heat, it decomposes and releases water vapor. This process cools the material, dilutes flammable gases, and forms a protective char layer, all while producing minimal smoke and no corrosive gases. The manufacturer's R&D team worked closely with Kyowa Chemical Industry Co. Ltd., to integrate KISUMA™ 5A into their existing manufacturing process, fine-tuning the formulation to maintain the desired tensile strength and flexibility of the cable insulation.
The Outcome
The adoption of KISUMA™ 5A delivered exceptional results across the board. The new cables successfully passed all major international fire safety standards, including V-0 UL94V test. Most importantly, the smoke density and toxicity levels were reduced compared to the previous halogen-based cables. This not only ensured compliance but also provided a critical safety advantage for end-users. Additionally, the integration of KISUMA™ 5A did not negatively impact production speed or product quality, allowing the manufacturer to maintain its competitive edge and expand into new markets that demand safer, more environmentally friendly products. This move solidified the company's reputation as an innovator committed to both performance and safety.
