Insulation is one of the components with the greatest influence on furnace performance.

A good or poor choice can make all the difference between efficient production and a significant waste of resources.

Learn more about the importance of insulation and what you should be looking at when choosing or changing your equipment’s insulation.

Article content:
How does the material used influence the insulation?
When to change the fiber for optimal furnace operation?


How does the material used influence the insulation?


The two most common material alternatives for this part of the furnace are:

A) Ceramic Fiber


Low density insulation.

  • Offers a significant advantage in intermittent furnaces, where the idea is to minimize heat waste and lower fuel consumption.

  • Allows faster heating and cooling since it does not store heat, which gives us a better response.

  • Reduced need for maintenance, as long as there are no impacts to the fiber that would damage it.

For these reasons, at Nutec Bickley we use ceramic fiber in our furnace insulation in applications where it is feasible and delivers, or will deliver, an operational advantage. This material is sourced from our sister company specializing in fiber products.

B) Refractory Brick


Insulating material characterized by greater hardness and density; therefore it demonstrates greater mechanical strength.

  • Stores more heat so its response to temperature changes is slower.

  • Consumes more fuel in an intermittent furnace since it heats up and cools down more slowly.


When to change the fiber for optimal furnace operation?


The main criterion affecting our decision to change the fiber system is whether its deterioration can adversely affect production or equipment, such as:

1.- There is a risk of product contamination


As the fiber ages it crystallizes, deforms, and pieces can then fall off.

  • For certain products such as sanitaryware or other porcelain products that require a flawless finish, this constitutes contamination, so ceramic fiber replacement would be necessary.

  • In the case of steel products this does not really affect product quality.


2.- Detection of hot spots that can damage equipment


The existence of a hot spot is a concern, not so much from the energy loss angle, but because it might damage an important system component.

If there is a heat leak in the insulation that could give rise to an operational problem or cause equipment to malfunction, it's time to change your insulation.

A couple of examples of this are:

  • Heat leakage can cause a valve to overheat and damage it, or burn out wires, thermocouples etc, and consequently adversely affect the operation.

  • In a car furnace, the heat can jam the wheels and prevent them from moving when inserting/removing the product.


If you are going to change your furnace’s insulation we suggest going for a complete overhaul rather than putting a patch/plug in place. This is not advisable as the fiber will shrink with temperature, creating a gap and can then make the situation worse.

At Nutec Bickley we are specialists in industrial furnaces and their various components. Contact our expert advisors to learn more about all the solutions we have available for you.

Author: Alberto Cantú, VP Combustion, Controls and Services

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