Aerogel felt is widely used for industrial pipelines, tanks, valves and high-temperature equipment because it provides strong thermal performance with a relatively thin insulation layer.

However, there is no single aerogel felt thickness suitable for every project. The correct thickness depends on the operating temperature, pipe diameter, ambient conditions, allowable heat loss and required outer-surface temperature.

This guide explains how to determine the appropriate aerogel felt insulation thickness and what information buyers should provide when requesting a recommendation.

Common Aerogel Felt Thicknesses

Aerogel felt is commonly available in the following thicknesses:

3mm

5mm

6mm

8mm

10mm

Some manufacturers can also provide other thicknesses or combine multiple layers to meet specific insulation requirements.

For example, aerogel thermal insulation felt can be supplied in 3mm, 6mm and 10mm thicknesses, while other aerogel blanket grades may be available in 5mm, 8mm and 10mm.

The selected thickness should be based on thermal calculations rather than product availability alone.

Why Thickness Matters

The insulation thickness directly affects three important project results:

Heat Loss

A thicker insulation layer generally reduces the amount of heat transferred from a hot pipeline or equipment surface to the surrounding environment.

Lower heat loss can help:

Reduce fuel and energy consumption

Maintain process temperature

Improve system efficiency

Reduce the load on boilers and heating equipment

Lower long-term operating costs

Outer-Surface Temperature

High-temperature pipes can create burn risks for workers. Increasing the insulation thickness helps lower the temperature of the external surface.

Projects involving personnel protection may specify a maximum allowable surface temperature.

Finished Insulation Diameter

A thicker insulation system increases the overall diameter of a pipe. This may affect:

Space between adjacent pipelines

Pipe rack layout

Access to valves and instruments

External metal cladding

Support and hanger design

Maintenance clearances

Because aerogel felt has relatively low thermal conductivity, it can often achieve the required thermal performance with less thickness than many conventional insulation materials.

What Determines the Required Thickness?

1. Operating Temperature

Pipeline or equipment temperature is one of the most important selection factors.

A low-temperature water pipe may require only a thin insulation layer, while a steam pipeline operating at several hundred degrees Celsius may require multiple layers.

Buyers should provide:

Normal operating temperature

Maximum continuous temperature

Short-term peak temperature

Minimum operating temperature

Frequency of startup and shutdown

The material must be suitable for the complete temperature range, not only the normal operating point.

2. Thermal Conductivity

Thermal conductivity describes how easily heat passes through a material. A lower value means better insulation performance at the same thickness.

Many aerogel felt products have a thermal conductivity of approximately 0.015–0.020 W/(m·K) at or near room temperature, depending on the product grade.

For example, Nano Aerogel Felt has a listed thermal conductivity of approximately 0.018–0.020 W/(m·K) at 25°C.

However, thermal conductivity normally increases as temperature rises. The thickness calculation should therefore use conductivity data at the project's actual mean operating temperature rather than only the value measured at 25°C.

3. Pipe Diameter

Pipe diameter affects the surface area through which heat is transferred.

A small-diameter pipe and a large-diameter pipe operating at the same temperature may require different insulation designs.

The buyer should provide the actual pipe outside diameter, not only the nominal pipe size.

4. Required Surface Temperature

Some projects select insulation thickness according to the maximum acceptable temperature on the outside of the insulation system.

This may be required for:

Personnel protection

Equipment located near walkways

Machinery rooms

Indoor processing areas

Protection of nearby cables and instruments

Compliance with site safety requirements

A thicker layer is normally required when a lower outer-surface temperature is specified.

5. Maximum Allowable Heat Loss

Energy-efficiency projects may define a maximum allowable heat loss per metre of pipe or per square metre of equipment surface.

When the permitted heat loss is low, the insulation thickness generally needs to increase.

The calculation should consider both the aerogel felt and the complete insulation system, including seams, fasteners, cladding and thermal bridges.

6. Ambient Conditions

The surrounding environment influences heat transfer from the insulated surface.

Important factors include:

Ambient temperature

Indoor or outdoor installation

Wind speed

Humidity

Rain exposure

Solar radiation

Air movement around the pipe

Outdoor pipelines exposed to strong wind may lose heat more quickly than identical pipes installed indoors.

7. Available Installation Space

Aerogel felt is particularly useful when installation space is limited.

Typical space-restricted applications include:

Congested pipe racks

Closely spaced process lines

Marine engine rooms

Offshore platforms

Valves near structural supports

Pipelines installed close to walls

Existing systems requiring insulation upgrades

In these situations, the lowest possible thickness that still meets the thermal requirement may be preferred.

8. External Cladding

The type and surface condition of the external cladding can affect heat radiation.

Common cladding materials include:

Aluminum

Stainless steel

Galvanized steel

Weather-resistant fabric

Removable insulation jacket coverings

The cladding material, surface emissivity and installation method should be included in a complete thermal calculation.

Typical Thickness Selection Guide

The following table provides general guidance only. Final thickness must be confirmed using actual project data and thermal calculations.

These ranges should not be treated as fixed product specifications. A 10mm layer may be sufficient for one pipeline but inadequate for another operating at a higher temperature or exposed to stronger wind.

Single Layer or Multiple Layers?

Aerogel felt can be installed as one layer or as a multi-layer system.

For example:

6mm total thickness: one 6mm layer

10mm total thickness: one 10mm layer

20mm total thickness: two 10mm layers

30mm total thickness: three 10mm layers

Multiple layers are often preferred for high-temperature pipes because they make it easier to:

Achieve greater total thickness

Stagger joints between layers

Reduce direct heat-transfer paths

Fit the material around curved surfaces

Replace only a damaged external layer

Improve insulation continuity

When multiple layers are installed, the longitudinal and circumferential joints should not be aligned.

Why Staggered Joints Matter

Even when the insulation material has low thermal conductivity, gaps between sections can allow heat to escape.

If the joints of several layers are positioned directly above one another, they create a more direct heat-transfer path.

Staggering the joints helps:

Reduce thermal bridging

Improve temperature uniformity

Limit heat leakage through seams

Improve the overall efficiency of the insulation system

All sections should be fitted closely without excessive compression or large open gaps.

Avoid Excessive Compression

Aerogel felt should be secured firmly, but it should not be heavily compressed.

Excessive compression reduces the installed thickness. Because thermal resistance is directly related to thickness, a compressed blanket may provide less insulation than expected.

For example, if a nominal 10mm layer is compressed to 7mm during installation, the installed system no longer provides the thermal resistance calculated for 10mm.

Stainless-steel bands, wires or other fasteners should hold the material in position without crushing it.

Aerogel Felt vs Traditional Insulation Thickness

Aerogel felt generally requires less thickness than mineral wool, glass wool or calcium silicate to achieve a similar thermal resistance.

The following example is only intended to explain the selection principle:

These figures assume that all materials are evaluated at the same temperature and under comparable test conditions.

Actual industrial calculations are more complex because thermal conductivity changes with temperature. Density, moisture, compression and installation quality can also affect the result.

Thickness for Condensation Control

For cold pipes, thickness selection is often based on condensation prevention rather than heat conservation.

Condensation occurs when the external surface temperature falls below the surrounding air's dew point.

The required thickness depends on:

Pipe temperature

Ambient temperature

Relative humidity

Air movement

Vapor barrier performance

Insulation thermal conductivity

Aerogel felt can provide good thermal performance within a thin layer, but the complete system must include properly sealed joints and a suitable vapor barrier.

Even a small opening can allow water vapor to enter the system and condense near the cold pipe surface.

Thickness for Personnel Protection

For hot pipelines located near workers, the insulation system may need to reduce the outer-surface temperature to a safe level.

The required thickness depends on:

Pipe operating temperature

Pipe diameter

Contact time

Ambient conditions

Cladding surface

Site safety requirements

Personnel protection and energy conservation do not always require the same thickness. A layer sufficient to prevent burns may still allow more heat loss than the project's energy-efficiency target.

Both requirements should therefore be evaluated separately.

Thickness for Valves and Flanges

Valves and flanges are more difficult to insulate than straight pipe sections because they have irregular shapes and must remain accessible for inspection and maintenance.

Aerogel felt is suitable for these areas because it can be cut and formed around complex components.

For valves and flanges, buyers should consider:

Component dimensions

Required access points

Bolt and stem clearance

Removable cover design

Number of aerogel layers

Outer fabric or metal covering

Fastening method

Repeated removal and installation

A removable insulation jacket containing several aerogel layers may be more practical than a permanently installed system.

Common Thickness-Selection Mistakes

Selecting by Temperature Alone

The highest temperature rating does not indicate how thick the insulation should be. It only shows whether the material can tolerate the temperature.

Using Room-Temperature Conductivity

Thermal conductivity at 25°C should not be used directly for a pipeline operating at several hundred degrees Celsius.

Ignoring Outdoor Wind

Wind increases convective heat loss from the insulated surface and may affect the required thickness.

Comparing Nominal Thickness Only

Two products with the same nominal thickness may have different conductivity, density and compression behavior.

Ignoring Installation Compression

The thickness after installation may be lower than the thickness stated on the product data sheet.

Failing to Insulate Fittings

Uninsulated valves, flanges and supports can account for significant heat loss, even when straight pipe sections are properly insulated.

Choosing the Thinnest Option Based Only on Price

The lowest initial material cost may result in higher long-term energy consumption if the insulation is too thin.

Information to Provide to the Supplier

To receive a reliable thickness recommendation, provide:

Pipeline or equipment application

Process medium

Normal operating temperature

Maximum and minimum temperatures

Pipe outside diameter

Total pipe length

Number of valves, elbows, flanges and tees

Required outer-surface temperature

Maximum allowable heat loss

Ambient temperature

Wind speed for outdoor installations

Indoor or outdoor environment

Available installation clearance

Required fire classification

External cladding material

Project quantity and delivery location

The supplier can then recommend the appropriate aerogel felt, number of layers and installation method.

Frequently Asked Questions

Is 10mm aerogel felt enough for a high-temperature pipe?

It may be sufficient for some applications, but pipe temperature, diameter, ambient conditions and allowable heat loss must be considered. High-temperature systems often require multiple layers.

Can two 10mm layers be used instead of one 20mm layer?

Yes. Two 10mm layers can provide a total nominal thickness of 20mm. Their joints should be staggered to reduce thermal bridging.

Does thicker aerogel felt always provide better insulation?

Greater thickness generally increases thermal resistance, but the system should be optimized according to the technical target and project cost. Installing more material than necessary may not provide sufficient additional benefit.

What is the minimum aerogel felt thickness?

Some products are available from approximately 3mm. Thin grades are useful for limited spaces, complex equipment and applications where only moderate thermal resistance is required.

Should the insulation be compressed during installation?

No. The material should be held securely without excessive compression because reducing the installed thickness lowers thermal resistance.

How do I compare aerogel felt thickness with mineral wool?

Compare the thermal resistance at the same mean temperature rather than comparing thickness alone. Aerogel felt can generally achieve similar insulation performance with a thinner layer.

Conclusion

The correct aerogel felt thickness depends on much more than operating temperature. Pipe diameter, thermal conductivity, allowable heat loss, surface-temperature requirements, ambient conditions and available installation space must all be considered.

Thin 3–10mm grades may be suitable for condensation control, restricted spaces or individual equipment components. High-temperature pipelines, tanks and vessels may require two or more layers to achieve the required performance.

For reliable selection, buyers should provide complete operating and installation data and request a thermal calculation based on conductivity values at the actual service temperature. This ensures that the aerogel felt system provides the right balance of thermal performance, installation thickness and lifecycle cost.