Innovative Stone-Based Insulation for Enhanced Water and Fire Protection

Photo courtesy of ROCKWOOL.

Water and fire. The ancient Greeks considered them two of the fundamental elements of matter. But at the modern industrial plant, they bring unwelcome risks and challenges. Water ingress onto the surface of operation-critical equipment and piping causes a range of issues, including unanticipated heat loss and unplanned downtime. Meanwhile, fire poses an obvious and critical threat to people and assets, particularly at plants where hydrocarbons are present. In both cases, however, selection of appropriate insulation solutions will help mitigate the challenge.

Stay ahead of water

Water can find its way under any type of insulation and collect on the metal surfaces of equipment and piping. One result of this, is corrosion under insulation (CUI). CUI typically occurs in cyclic plant operations running below 347°F (175°C) and – if undetected – may cause leaks that are hazardous to both plant personnel and equipment, as well as damaging to the company’s ESG metrics and reputation. By some estimates, CUI accounts for up to 40% to 60% of pipe maintenance costs at petrochemical facilities.1

In response to the CUI challenge, ROCKWOOL Technical Insulation developed ProRox® with WR-Tech™ (Water Repellency Technology) stone wool insulation. WR-Tech incorporates an innovative, hydrophobic binder additive that coats each individual insulation fiber during production, to deliver low water absorption and fast dissipation over the critical CUI temperature range, even after prolonged aging and multiple heating cycles. Importantly, WR-Tech also contains low leachable chloride levels and is silicone oil-free, in compliance with the strictest design standards.

WR-Tech was first successfully launched in ROCKWOOL’s mandrel wound pipe sections, where it quickly demonstrated reliable, CUI protection and sustained thermal resistance to keep plant processes operating at their peak. ROCKWOOL recently expanded our innovative WR-Tech into our ProRox MA 960 mat/wrap product. The ProRox MA 960 solution is designed to provide superior CUI protection for large-diameter pipework, vessels, columns, and other plant applications that require design flexibility. Extensive testing has shown it to be five times more water repellent at 482°F (250°C) that standard EN-compliant stone wool.

A number of other performance benefits further assist in optimizing plant operations. These include excellent acoustic and thermal resistance, thanks to its stone-wool base. For example, a ProRox MA 960 insulation-based system meets the ISO 15665 standard for recommended insertion loss levels for Classes B and C – at less than half the thickness of other insulation materials. It is considered a dual “thermal-acoustic” solution in one material, as it also minimizes heat losses from hot pipes with its proven stable thermal performance over time. This reduces plant energy consumption – a key cost driver – while also lowering energy-related carbon emissions.

Passive fire prevention

Fire poses a significant risk to all industrial plants. But this is particularly true at plants handling hydrocarbons, such as petrochemical plants and oil/gas processing plants. Hydrocarbon fires burn faster and hotter that wood or cellulosic fires, reaching peak temperatures of up to 2000°F (1100°C) in less than five minutes. In contrast, cellulosic fires can take many hours to reach peak temperature, which is also much lower, at only 1100°F (600°C) .

Hydrocarbon fires therefore allow far less time for plant personnel to react to avoid injury and mitigate damage. These fires also have far greater potential to cause catastrophic damage to plant equipment and structures and take a significant toll on the air quality of the surrounding environment. The end result is significant downtime for unplanned repairs and rebuild, a major hit to a company’s financial and ESG performance, and the risk of substantial reputational damage.

Fire resistant insulation plays a significant role in reducing the risk posed by fire. This is a risk that can never be completely eliminated; however, selecting the best available technology can make the difference between a localized and contained fire and that which results in devastating loss to life and property. ROCKWOOL ProRox PS 680 pipe insulation with FR-Tech (Fire Resistant Technology) was developed with this aim. This mandrel-wound stone wool-based pipe insulation solution slows the transfer of heat to steel structures and equipment, giving plant personnel critical additional time to evacuate; it also helps slow the fire’s spread, aiding attempts to contain it and reduce its impact.

Passive fire protection materials are typically tested to the industry recognized UL 1709 standard, which requires materials to protect equipment and maintain structural integrity for at least 30 minutes in a 2000°F (1100°C). However, most plant owners specify at least two hours of passive fire protection. ProRox PS 680 is designed to meet these higher standards: in one- and two-hour UL 1709 fire test scenarios, ProRox PS 680 consistently maintains the core temperature of the pipe below 1000°F (537°C), at a range of nominal pipe sizes and minimal insulation thickness, for steam and pipe systems operating up to 1400°F (760°C).

ProRox PS 680 pipe insulation also incorporates WR-Tech water repellency technology. So, the product is truly optimized to be a physical barrier: protecting from the threats of both water and fire.

The stone wool advantage

In addition to the water and fire resiliency benefits of specific ROCKWOOL ProRox insulation products, the company’s stone wool-based solutions deliver a range of general benefits over other alternative offerings.

With fewer application layers than conventional alternative products, ProRox stone wool-based insulation solutions are simpler and faster to install. ProRox can be applied easily to vessels, columns, and complete pipeline systems – even around fittings/bends – without the need for sealants, offsite cutting, or specialized personal protective equipment. ProRox also requires noticeably less thickness as compared to most conventional insulation solutions, making it much easier to apply around tight pipe bends or in areas with limited clearance. And it is removable and reusable, allowing for easy inspection, without the need to purchase replacement materials. These features combine to lower maintenance and replacement costs.

ROCKWOOL ProRox industrial insulation products are made in North America. To learn more about how these innovative solutions can help solve your operating and maintenance challenges—now and in the future—visit