Stone Wool Insulation Advances Improve Water Repellency to Stay Ahead of CUI

Photo Courtesy of ROCKWOOL

Water is a major challenge for many process-intensive industries. In a plant, water often finds its way onto the surface of operation-critical equipment and piping, even those covered in insulation. Water can move through any type of insulation to the metal surface—leading to unanticipated heat loss, unplanned downtime, and leaks and spills due to corrosion under insulation (CUI).

CUI typically occurs in cyclic plant operations running below 347°F (175°C), with dangerous and expensive consequences. By some estimates, CUI accounts for 10% of a plant’s overall maintenance costs and up to 60% of pipeline maintenance costs. Leaks caused by CUI can pose hazards for plant personnel while damaging the plant’s ESG metrics and reputation.

ROCKWOOL Technical Insulation has developed a stone wool insulation solution that helps plant operations stay ahead of water and keep CUI at bay. The next-generation ProRox® Mat (Wrap) MA 960 with WR-Tech™ provides superior thermal and acoustic insulation performance and CUI protection for large-diameter pipework, vessels, columns, and other plant applications requiring design flexibility.

Award-Winning Corrosion Protection

ProRox MA 960 incorporates ROCKWOOL’s proven WR-Tech technology, a revolutionary low-chloride, water-repellent binder that coats each individual insulation fiber to combat CUI. Extensive testing confirms that WR-Tech makes ProRox MA 960 five times more water repellent (at 482°F/250°C) than standard EN-compliant stone wool, even after heating and aging.

ProRox insulation with WR-Tech has been keeping critical plant systems dry since 2017. The technology won the prestigious AMPP 2019 Corrosion Innovation of the Year Award, one of 10 technologies out of more than 50 nominees to receive the honor.

WR-Tech consistently delivers long-lasting CUI suppression, with features including:

  • Low leachable chloride content and silicone oil-free, in compliance with the strictest design standards
  • Low water absorption and fast water dissipation, even after prolonged aging and multiple heating cycles
  • Durable insulation and water-repellency performance over the critical CUI temperature range.

ProRox MA 960 extends ROCKWOOL’s 80-year history of providing cost-effective, robust, and reliable stone wool insulation solutions for a range of industrial applications. In addition to excellent water repellency, this insulation technology features several other performance benefits for optimized plant operations.

  • Installs easily with less downtime. With fewer application layers than conventional insulation options, ProRox MA 960 is faster and easier to install. The mat (wrap) insulation applies easily to vessels, columns, and complete pipeline systems—including around bends—without the need for sealants, offsite cutting, or specialized personal protective equipment.
  • Frees up space in tight places. ProRox MA 960 installs at a fraction of the thickness of conventional insulation materials, making it easier to apply around tight pipe bends or in areas with limited clearance space.
  • Lowers maintenance and replacement costs. ProRox MA 960 is removable and reusable, allowing for easy inspection without having to purchase replacement materials.
  • Delivers effective acoustics suppression in a thinner profile. In addition to excellent thermal insulation performance, ProRox MA 960 delivers effective acoustics insulation for inherently noisy plant operations. With stone wool as its base material, ProRox MA 960 effectively meets ISO 156665 standards for recommended insertion loss levels for Classes B and C—at less than half the thickness of other insulation materials.
  • Minimizes a plant’s carbon footprint. ProRox MA 960 minimizes heat losses in hot pipes to save on energy consumption and greenhouse gas emissions for the plant. On average, stone wool insulation saves 20,000 times more CO2 over its operating life than what is emitted during production.

ProRox MA 960 is made in North America for plant operations requiring reliable and durable water protection. Plant engineers are upgrading their specifications to include WR-Tech, while operators are moving quickly to install ProRox MA 960 on their piping systems—saving time, costs, and manpower compared to conventional insulation solutions.

To learn how ProRox MA 960 with WR-Tech can help you stay ahead of water—now and in the long run—and safely protect your plant from CUI, visit