What is the Difference Between PIR and Phenolic Board?

In the construction and insulation industries, selecting the right material is critical to achieving both energy efficiency and fire safety. Polyisocyanurate (PIR) and phenolic boards are two popular options, each with unique properties that make them suitable for different applications.

In the construction and insulation industries, selecting the right material is critical to achieving both energy efficiency and fire safety. Polyisocyanurate (PIR) and phenolic boards are two popular options, each with unique properties that make them suitable for different applications. Here, we explore their differences in terms of composition, thermal insulation properties, fire resistance, moisture performance, and cost.

Understanding the Basics: PIR vs. aluminium composite panel

PIR (Polyisocyanurate) Board is a type of thermoset plastic that has gained widespread use as insulation. Known for its high thermal performance and strength, PIR is typically chosen for roofing, walls, and floors in both residential and commercial buildings. Its lightweight nature makes it easy to install, and it offers substantial resistance to heat flow, making it a good choice for energy-efficient buildings.

Phenolic Insulation Board, on the other hand, is made from a phenolic resin that is expanded into a rigid foam, usually with closed cells to trap air and enhance insulation. Phenolic boards have long been considered among the best for thermal performance and fire resistance, thanks to their high structural integrity under high temperatures. These boards are often used where fire safety is a top priority.

Key Differences Between PIR and Phenolic Insulation Board

1. Thermal Conductivity

The lower the thermal conductivity of an insulation material, the better its performance. Both PIR and phenolic boards have low thermal conductivities, though phenolic insulation board often holds a slight advantage. Phenolic boards generally have a thermal conductivity around 0.020-0.025 W/m·K, while PIR boards range around 0.022-0.026 W/m·K. This difference, although small, can be crucial when trying to meet stringent energy efficiency targets. For structures with space constraints, phenolic board may allow for thinner insulation layers while achieving similar thermal performance to PIR.

2. Fire Resistance

Phenolic insulation boards are widely recognized for their superior fire resistance. In the event of a fire, phenolic boards exhibit low levels of smoke emission and do not ignite easily, which makes them safer for applications in public buildings and high-rise constructions. PIR, while better than many other forms of insulation (like polystyrene), is generally less fire-resistant compared to phenolic boards. Although both materials are thermoset plastics and won’t melt when exposed to high temperatures, phenolic insulation’s inherent properties often make it the preferred choice for fire safety-focused projects.

3. Moisture Resistance

PIR insulation material and phenolic board are both closed cell structures with high waterproofness, making them ideal choices for applications that focus on moisture exposure, such as roofs or moisture proofing. After soaking the phenolic board in all directions for 7 days, the water absorption rate is less than 6%! It can maintain its insulation performance even when exposed to humid environments.

4. Compression and Structural Strength

In terms of mechanical strength, phenolic boards are often superior to PIR boards. The compressive strength of phenolic board mainly depends on its density and formula. Generally speaking, phenolic board has a high compressive strength, which can reach 0.6 MPa or even higher. The PIR board may vary in specific values due to differences in density and formulation. When the density of polyurethane is 35-40kg/m ³, its compressive strength can reach over 0.6MPa.

5. Environmental and Health Considerations

Both PIR and phenolic insulation have environmental impacts, primarily due to their production processes and material composition. PIR boards are derived from petrochemicals, and while manufacturers are working on reducing their carbon footprints, the product's environmental impact is often higher than phenolic boards. On the other hand, the phenolic board is manufactured using fluorine free foaming, which can achieve ENF level safety and environmental protection.

6. Cost

Cost is always a significant factor in any construction project, and PIR insulation is typically expensive than phenolic boards. PIR insulation materials themselves do not have flame retardancy, and in order to achieve a certain level of fire resistance, a large amount of flame retardants need to be added. Phenolic boards themselves have flame retardancy and excellent insulation performance! So phenolic board has extremely high cost-effectiveness!

Applications and Choosing the Right Material

The ideal choice between PIR and phenolic insulation boards largely depends on the specific requirements of a project:

- Phenolic Board Applications: Phenolic insulation board is favored in high-rise buildings, hospitals, schools, and other public buildings where fire safety is paramount. Its higher resistance to fire and minimal smoke emission make it a safer choice for these sensitive environments. Additionally, for energy-efficient construction projects where space is limited, phenolic board's slightly better thermal performance allows for thinner walls, maximizing internal space without sacrificing insulation quality.

- PIR Board Applications: PIR insulation is widely used in residential construction, commercial buildings, and for projects on a budget. Its combination of thermal efficiency, moisture resistance, and compressive strength make it versatile enough for use in roofs, walls, and floors. It’s particularly popular in roofing applications, where its water resistance and thermal performance contribute to long-lasting, weather-resistant structures.

Conclusion: Which Insulation is Right for Your Project?

The choice between PIR and phenolic insulation boards depends on the specific needs of the project. If fire safety and superior thermal performance are primary concerns, phenolic insulation board is the better choice, especially in high-rise or public buildings.

Both PIR and phenolic insulation boards offer unique benefits, and as insulation technology advances, we can expect to see even better options on the market that further enhance building safety and efficiency.

 

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