Unifrax Thermal Management Blog

January 2021

This blog was authored by Allan Davies, Unifrax Product Manager, Industrial Thermal Management

Fiberfrax® Durablanket® LT and Durablanket LT Z

Our biggest breakthrough in alumina-silicate insulation in years. 

The reinvention of anything is always sensational. Since the 1960’s, Fiberfrax  Durablanket  insulation products have been known and trusted for their performance, versatility and handling in a broad spectrum of industries where high temperature applications place extraordinary demands on insulating components.

Now, using advances in manufacturing innovation learned from the development of our market leading Insulfrax® range, we’re introducing a new Durablanket product line. Produced with the aid of proprietary technology adapted from a spinning based fiberization process for AES wool, Durablanket LT and LT Z is a breakthrough RCF product that delivers outstanding thermal performance up to temperatures 2450 oF.

This new production technology also means Durablanket LT and LT Z offers improved handling for safer, quicker and easier installation, as well as increased durability and tensile strength that allows it to perform for longer, even in the most extreme conditions.

As a result, it is ideally suited to a wide range of applications, including:

  • Billet slab/reheat furnaces
  • Furnace door linings and seals
  • Boiler insulations
  • Pipe and duct insulation
  • Chemical process heaters
  • High temperature seals and gaskets

Strength That’s Easier To Handle

Unifrax’s proprietary manufacturing process used to produce Durablanket LT and Durablanket LT Z results in a blanket with a higher index of interlocking fibres and a reduced shot content that makes it easier to form and handle while providing class-leading tensile strength.  This high tensile strength – 80 kPa for Durablanket LT, – means Durablanket LT is harder to pull apart, making it more robust during installation, and much more resistant to stress due the expansion of casings and components under extreme heat.

Put Simply:  The Best Ever Durablanket Thermal Performance

Having 20% lower thermal conductivity compared to the next best available RCF blanket material means real energy savings in all applications within the ferrous, non-ferrous metals and the power industry and a payback periods in just several months of service.

Instead of taking advantage of the energy savings alone, Durablanket LT’s low thermal conductivity performance can be leveraged through a reduction in blanket weight and/or thickness creating more available space in furnaces and ovens.  For example, at 96 kg/m3 , Durablanket LT provides the same insulation performance as a standard 128 kg/m3 blanket product, which can result in a weight saving of up to 25%.




Exceptional insulating characteristics (Low thermal conductivity) Reduced insulation thickness and weight = Choice of energy savings or material cost savings
More fibers (Higher fibre index) Improved energy savings
Reduced shot content and particle size Lower cold face temperatures
Less surface shot and “dustiness” Cleaner workspace and operator satisfaction
Improved handling and tensile strength Easier installation, saving time and waste
Smoother and softer feel

Less skin irritation

Energy Savings and Sustainability

One of the key challenges our customers are faced with are rising worldwide energy prices. Across  industries of every kind, customers are looking to reduce their energy consumption as much as they can. Added to this, the demands on these same industries to reduce emissions in line with local regulations and international agreements make Durablanket LT and LT Z a natural choice when it comes to increasing thermal efficiency, reducing costs and honouring CSR commitments to sustainability. Durablanket LT and LT Z can reduce energy costs by 15-20% on average!

More Fiber

Durablanket LT has a high fiber index, higher than standard RCF blanket. Unlike fiber, shot (un-fiberized particulate), a by-product of the fiber manufacturing process, is not an efficient blocker of thermal radiation. The fiber properties of Durablanket LT have been optimized to minimise the shot content and reduce the size of shot. The result – superior thermal performance. This is also enhanced by producing a blanket with a softer feel and improved handling.

Longer Lifetime

30% more fiber per unit mass and fewer large shot particles allow the remaining small shot to be ‘locked away’ from the surface resulting in minimal free particles in the fiber matrix. Simply put,  Fiberfrax Durablanket LT and LT Z  Blankets provide a longer lifetime in high vibration – high temperature environments.

 Blanket and Module Formats

 Durablanket LT and LT Z are available as a needled blanket product, or as insulation modules. In either format, it is easy to work with. Little dust is given off during installation, and thanks to its smoother, softer surface, there is less likelihood of skin irritation.

 Experience You Can Count On

Durablanket products have been used successfully for decades in applications for ferrous and non-ferrous metals, power generation and other industries worldwide. Now, Durablanket LT and LT Z deliver even better thermal performance and an even longer service life in product that leads in every critical performance characteristics.

Unifrax has the broadest range of in-house manufactured, high temperature insulation wool found worldwide, and is committed to maintaining the long Durablanket legacy of quality and performance.

Unifrax Worldwide

Unifrax is a global leader in high-performance specialty products used by many industries in a diverse group of applications. Our products provide substantial improvement in thermal performance, save thousands of dollars in energy costs and can help reduce your operations environmental footprint. Unifrax is committed to producing high quality products that help our customers save energy, reduce pollution and improve fire safety.

If you would like to learn more about how Durablanket LT and LT Z  can improve your performance and efficiency, be sure to check out the following resources:

Watch the Durablanket LT and LT Z video: 

Download our new Durablanket LT / LT Z Brochure 

For more information, link to our product information and datasheets


Let us help you find what you’re looking for.