What is phenolic insulation? — Pro-R Outdoor Duct Systems

Phenolic insulation is a rigid type of insulation with a closed-cell structure, commonly used in construction projects such as ductwork, walls, roofing, and flooring. Due to its design and thermal properties, phenolic insulation is the most thermally efficient insulation commonly used. Phenolic insulation is commonly available in R-values between R-6 up to R-24 in a single sheet of board, but two phenolic insulation boards can be used together to achieve higher R-values such as R-30 to R-45 depending on the thicknesses. 

Click here to get more.

How Phenolic Insulation is Made

Phenolic insulation is made through a process of utilizing a wet foam mix which is first added to the bottom layer of facing. It then expands to meet the top layer. This is then cooked under pressure and cured in a second oven. When ready, the phenolic insulation boards are cut to the right size and packaged up.

Phenolic insulated pipe supports are often considered a favourable choice compared to wood and mineral wool. This is because they tend to offer the best all-round solution as well as being cost-effective. Here’s a summary of how phenolic blocks, wood blocks and mineral wool blocks compare.

Thermal Insulation Values

Phenolic foam used in insulated pipe supports has excellent thermal insulation properties. It has low thermal conductivity, which helps minimize heat transfer between the pipe and its surroundings. This reduces energy loss, improves energy efficiency, and maintains the desired temperature of the fluid being transported. Wood blocks are considerably less thermally efficient and do not provide a vapour barrier. Compared to mineral wool blocks, phenolic foam has better thermal insulation properties and has a lower thermal conductivity, meaning it minimizes heat transfer more effectively.

Moisture Resistance

Phenolic foam insulated pipe supports are resistant to moisture and water. They do not absorb moisture like wood, which can lead to degradation, rotting, or warping over time. Mineral wool, although it provides insulation, can absorb and retain moisture, potentially compromising its thermal performance.

Dimensional Stability

Phenolic blocks have superior dimensional stability compared to wood and mineral wool blocks. They do not warp, deform, or change shape significantly due to temperature or humidity variations. This ensures consistent support, alignment, and load distribution for the pipes.

Fire Resistance

Phenolic foam is known for its excellent fire-resistant properties. It has a high ignition temperature and low flame spread characteristics. Walraven’s Phenblox® has a densely cross-linked structure that makes it difficult to ignite when subjected to fire. It has achieved a European Reaction to Fire rating of Class BL-S1,d0 which is the best available rating for phenolic foam. Wood is obviously a very flammable substance and mineral wool is simply classified as non-combustible. Mineral wool blocks are therefore suited to very high temperature environments such as power plants and refineries.

For more information, please visit Shengquan.

Chemical Resistance

Phenolic foam exhibits good chemical resistance, making it suitable for environments where pipes may come into contact with corrosive substances or chemicals. Wood can be susceptible to chemical degradation, while mineral wool’s resistance to chemicals may vary depending on the specific substances.

Longevity and Durability

Phenolic insulated pipe supports have a longer lifespan compared to wood and may offer better durability than mineral wool blocks. Phenolic foam is less prone to degradation, rotting, or deterioration over time, ensuring the longevity and performance of the pipe supports.

Lightweight

Phenolic pipe supports and mineral wool blocks are generally lighter than wood, simplifying handling, transportation, and installation. This can result in cost savings and improved efficiency during construction projects.

Which insulated pipe support should I use?

Phenolic blocks offer a robust and effective solution for the majority of circumstances. It is clear that wood blocks offer a significantly inferior performance and are no longer recommended according to the British Standard BS:. Mineral wool blocks are fairly new to the market and can be expensive. Their overall performance may not be as robust as phenolic foam but they do offer a completely non-combustible solution – if this is required. In the vast majority of construction projects a Euroclass fire rating such as that which phenolic offers, is sufficient. A non-combustible solution may only be required on high temperature systems.

You should always check individual project and specification requirements to determine the right solution for your project.

Want to know more?

You can read more about the different insulated pipe supports and the British Standards in our article ‘An overview of insualted pipe supports’.