The Sweet Spot of Micro Fiberglass Filtration Media: Proven Safety, Proven Performance

Air filtration has always been defined by core performance: particle efficiency, pressure drop, and lifetime. But in recent years, another question has become just as important and critical: How safe are the materials inside the filter itself? 

Manufacturers, OEMs, and system operators want clear science-based answers - especially when fine fibers are involved. 

This is exactly where biosoluble micro fiberglass makes a difference. Biosolubility describes how specific glass chemistries dissolve naturally in the body if very fine fibers are inhaled. In other words: the glass is engineered to be safe by chemistry, not by chance. 

And when this safety foundation meets the stable, high efficiency performance micro fiberglass is known for, you reach what we at Johns Manville call the Sweet Spot of Micro Fiberglass. 
It’s the point where  exceptional health protection and filtration performance come together - and JM has been building its micro fiberglass portfolio precisely in this space for more than 30 years. 

What Biosolubility Really Means - and Why It Matters 

To understand why biosoluble glass plays such an important role today, it helps to look at the fundamentals.  

Very fine fibers can become respirable depending on their diameter, length, and aspect ratio. According to the World Health Organization definition, respirable fibers are those smaller than 3 µm in diameter, longer than 5 µm, and with a length‑to‑diameter ratio of at least 3:1. If these fibers are made from a glass or synthetic (Kommentar C.H: müssen wir noch besrpechen ob wir das so sagen können) chemistry that is not biosoluble, they may persist in the lungs much longer than they should. That’s why the EU’s CLP Regulation requires manufacturers to demonstrate, through established scientific testing, whether their specific chemistry is bio persistent or not. 

This is where Note Q becomes essential. It defines recognized scientific test methods - including short-term inhalation, intratracheal instillation, and long-term studies - that can confirm a chemistry is not bio persistent. 

Johns Manville performed this testing for the glass chemistries used in our microfiber glass filter media. Our biosoluble glass met the Note Q criteria through a short-term intratracheal instillation test, showing a weighted half-life below 40 days for fibers longer than 20 μm. 

For customers, this means clarity: the glass chemistry used in JM’s micro fiberglass media is scientifically proven to be biosoluble. 

Safety and Performance - Both Essential, Both Non-negotiable 

Once safety is clear, the next question is straightforward: How does the material perform? 
Because in filtration, performance is never optional. 

This combination of safe chemistry and reliable performance is the essence of the Sweet Spot - a carefully engineered balance of two equally important requirements.

Why Micro Fiberglass Delivers the Performance Filtration Needs 

Micro fiberglass media is uniquely suited for high-efficiency mechanical filtration thanks to: 

• High efficiency at low pressure drop 
• Mechanical performance independent of electrostatic charge 
• Stable efficiency throughout the entire filter lifetime 
• Reliable performance in demanding environments 
• Effective capture of fine and submicron particles 

This stability is increasingly critical in modern applications like industrial HVAC, cleanrooms - and especially - AI data centers, where even minor declines in filtration performance can directly impact operations. 

How Today’s JM Micro Fiberglass Media Behaves in Practice 

Discussions about fiber behavior, including shedding, still appear in some corners of the market - often based on impressions from decades ago. Johns Manville’s micro fiberglass media today is the result of continuous improvement and strict process control. 

Today’s JM micro fiberglass media features: 

• A stabilizing backing veil on the downstream side 
• Advanced binder systems that secure fiber structure 
• Tight process control ensuring clean, stable media 
• Verified fiber erosion performance through testing 

Both glass and synthetic fibers can behave differently depending on the application. What matters is selecting the right material for the right environment - and for high efficiency mechanical filtration, low energy consumption during use, and high dust holding capacity for a long filter lifetime JM’s micro fiberglass media remains the benchmark. 

The Importance of Verifying Biosolubility Claims 

Around the world, filtration manufacturers may encounter glass media that looks similar to established JM’s micro fiberglass but lacks clarity on biosolubility or proper labeling. Independent evaluations of some available products show: 

• a lack of verified biosolubility documentation 
• chemistries that do not meet established criteria 
• missing labeling for respirable fibers 

These gaps can create serious risks for manufacturers, operators, and end users. 

JM’s approach: be transparent, responsible, and support customers with science-driven information. 

The Sweet Spot of JM’s Micro Fiberglass: Where Health Meets Performance 

Everything we do in our micro fiberglass portfolio is built around one idea: 
The best filtration solutions deliver both safety and performance - not one or the other. 

This is the Sweet Spot of JM’s Micro Fiberglass: 

• Proven biosolubility, verified through recognized testing 
• Consistent, long-term mechanical performance in combination with low energy consumption during use, and high dust holding capacity for a long filter lifetime 
• Stable fiber structure engineered for modern filtration demands 
• More than 30 years of production expertise 
• Reliable, local production and supply from facilities in Europe and North America 
• Transparent communication that customers can trust 

As air filtration becomes more critical across industries, JM’s biosoluble micro fiberglass provides a dependable foundation for filters that must perform - and protect. 

If you’d like to learn more about our biosoluble micro fiberglass technologies or discuss your application needs, our team is ready to support you. 

Executive Summary – The Ideal Intersection of Safety and Performance 

JM’s biosoluble micro fiberglass represents the ideal intersection of safety and performance in modern air filtration. Its engineered glass chemistry ensures biosolubility and compliance with EU Note Q - providing verified health safety even for very fine, respirable fibers. 

Simultaneously, JM’s micro fiberglass filter media delivers stable, high‑efficiency mechanical filtration with low pressure drop, long service life, and consistent performance over the entire filter lifetime. Advanced binder systems, precise process control, and decades of manufacturing expertise ensure that the media performs reliably in demanding applications - from industrial HVAC to cleanrooms and emerging AI data centers. 

Johns Manville’s biosoluble micro fiberglass offers a trusted, science‑based solution for organizations that require both uncompromising safety and uncompromising performance.