Could Your PPE Be Making Molten Splash More Dangerous?
How the right PPE protects from molten splash hazards.
- By Mary Ann Merikoski
- Oct 15, 2024
When most people hear “molten splash,” they might imagine splashes of molten metal or a dramatic industrial incident. But molten splash hazards are far more nuanced, and the hazards are more complex and dangerous than just high temperatures. While many are familiar with fire-retardant PPE and fabrics, fewer understand the critical role of how these materials interact with the substances involved — and that’s where the real challenge in protecting workers begins.
Molten splash, also known as hot splash, involves not just extreme heat but direct contact with highly reactive and caustic substances that can aggressively attack PPE materials. Imagine molten metals like iron or aluminum, or chemicals like sodium hydroxide, not just burning through fabric but also corroding it, causing rapid degradation and rendering the protective gear ineffective. It’s not just about the heat—the real danger is in how these substances interact with PPE, turning a protective barrier into a potential liability. This is why selecting the right PPE material isn’t just important—it’s a critical decision that directly impacts worker safety.
What Causes Molten Splash?
Molten splash occurs when water, moisture, or any liquid meets molten substances, typically metals like iron, aluminum, or zinc. But it’s not limited to metals; molten splash can also result from non-metallic substances such as asphalt, pulp and paper liquors, or slurries. Even a hot furnace exposed to water can trigger this hazard.
When molten splash contacts a person, it can burn through clothing and cause severe or even fatal injuries. Workers often rely on multiple layers of heat-resistant PPE, which provides a critical shield of protection until help arrives or immediate actions can be taken.
How Does PPE Material Affect Protection?
The choice of material is crucial to protect against molten splash. Different fabrics have unique properties that determine their effectiveness against specific substances, heat levels and temperatures.
Some key fabrics used for molten splash protection include:
• Aluminized fabrics offer protection against high radiant heat and certain molten metal splashes but lack breathability.
• FR cotton works well for secondary protection in routine steel production tasks. But workers in high-risk zones need primary protection from more materials such as aluminized fabrics.
• Technical fabrics are designed with shedding properties. They may include wool for its natural metal-shedding and thermal insulation, or vinal fibers for chemical resistance, offering protection without needing a second layer like aluminized fabrics.
Inherent Fibers vs. Treated Fibers vs. Coated Fabrics
Safety managers have options among FR garments made from inherent fibers, treated fibers or coated fabrics.
Inherent fibers have built-in flame resistance that does not degrade with use or washing. Treated fibers, like FR cotton, have limited durability compared to inherent fibers but still meet safety standards. Coated fabrics, on the other hand, can be made of either inherent or treated fibers, which are then coated in silicone or some other treatment to enhance their shedding properties.
The primary differences lie in performance, weight and comfort. Inherent fibers like aramids are stronger, allowing for a lighter weave, which makes garments lighter and more comfortable for extended wear.
Think of inherent fibers like a solid metal fence: strong and reliable on its own, requiring less material to do the job effectively. In contrast, treated fibers are more like a wooden fence with a protective paint layer. It still works, but it needs extra protection to withstand the elements, making it heavier and less durable over time.
Standards Governing Molten Splash PPE
Several standards guide the design and use of PPE for molten splash protection. Key standards include:
• ASTM F955. This standard evaluates heat transfer through protective clothing when exposed to molten substances. It involves pouring 1 kg of molten metal onto fabric from a height of 305 millimeters, with temperature adjusted for each metal type. The fabric sample is positioned at a 70-degree angle to simulate draping and tested for heat resistance, damage, and substance adhesion.
• NFPA 1990. This standard covers protective ensembles for hazardous materials, with design and testing guidelines for manufacturers. Requirements include that garments must protect torso, arms and legs; gloves must protect from fingertips to at least one inch beyond the wrist crease; garments should be tested for liquid-tight integrity; and seams and closures must resist penetration.
Molten Splash: A Manageable Hazard
Although molten splash is a serious hazard, its risks can be significantly reduced by understanding molten behavior, temperature exposures and selecting the right PPE. However, PPE alone is not sufficient; proper safety procedures and practices are essential. Many incidents occur when workers, despite having the correct PPE, suffer severe injuries due to improper use, such as leaving fastenings open or wearing incomplete sets.
Stay Safe with the Right Materials and Practices
Mitigating molten splash hazards goes beyond just wearing any PPE. It’s about selecting materials that can withstand extreme heat and reactive substances. Inherent fibers, treated fabrics and aluminized options each play a role, but their effectiveness depends on proper use and comprehensive safety practices. Understanding the properties of these materials and ensuring proper use significantly reduces the risk of injuries and maintains a safer workplace.
This article originally appeared in the October 2024 issue of Occupational Health & Safety.