PU (Polyurethane), PIR (Polyisocyanurate), and PUR (often used interchangeably with PU, but specifically referring to a class) are all commonly used sandwich panel insulation materials, but they differ significantly in performance, cost, and applications.
To help you quickly understand, I have summarized the core differences in the table below:
Property Dimension | PU (Polyurethane) | Polyurethane | PIR (Polyisocyanurate) | Polyisocyanurate | PUR (often referring to a specific PU)
Core Chemical Definition | A basic class formed by the reaction of polyols and isocyanates. | A high-performance modified variant of PU, formed through specific formulations and processes to create a more stable isocyanurate ring structure. | Usually refers to a type of polyurethane, often used interchangeably with PU; sometimes specifically refers to the type of polyol used (e.g., polyester).
Fire Resistance | Relatively low. | Usually B2 (combustible) or B1 (flame-retardant), burns and produces molten droplets when exposed to fire. | Significantly better. | Usually easily reaches B1 (flame-retardant), high-quality products can reach A2 (near non-combustible). | Carbonizes during combustion, does not drip, and forms a protective layer. Similar to PU, depending on the specific formulation.
Insulation Performance: Excellent initial thermal conductivity, approximately 0.022 – 0.028 W/(m·K). More stable long-term insulation. Initial thermal conductivity comparable to PU, but its insulation performance degrades more slowly over long-term use, resulting in higher energy efficiency throughout its life cycle. Similar to PU.
Temperature Resistance: Moderate, long-term operating temperature approximately -50℃ ~ 110℃. Superior. Can withstand short-term high temperatures of -200℃ ~ 150℃, suitable for high-temperature environments. Similar to PU.
Mechanical Strength: Good, good adhesion to panels. Higher. At the same density, its strength and stiffness are generally superior to PU, with better compressive and bending resistance. Similar to PU.
Cost: Lower. Most economical in terms of raw material and processing costs. Higher. Due to more complex formulations and processes, it is typically 15%-30% more expensive than PU. Similar to PU.
Cost: Lower. Most economical in terms of raw material and processing costs. Higher. Due to more complex formulations and processes, it is typically 15%-30% more expensive than PU. Main Application Scenarios: Temporary buildings, general warehouses, and workshops where cost is sensitive and fire protection requirements are not extremely stringent. High-end and strictly regulated scenarios: cleanrooms, cold storage facilities, airports, convention centers, high-rise buildings, and prefabricated cabins/containers with high fire protection requirements. Commonly used in specific industrial or furniture sectors.
📌 How to Choose for Your Project?
Based on your power project and container construction, the following selection suggestions are offered:
For Temporary Offices:
If local building codes are not strict on fire protection requirements for temporary buildings and the project budget is limited, PU boards are an economical choice, meeting basic thermal insulation needs.
If the project is located in an area with high safety requirements, or if you want to improve product image and durability, PIR boards are recommended.
For Substation Control Rooms:
PIR boards are strongly recommended as a priority because:
Fire Safety: Electrical equipment poses a fire risk; the higher fire resistance rating of PIR boards provides longer safe escape and fire extinguishing time.
Long-term stability: Control rooms require constant temperature and humidity year-round, and the more stable long-term insulation properties of PIR help reduce operating energy consumption.
Mechanical strength: The higher strength of PIR panels makes them more suitable for walls where heavy-duty cabinets may be installed internally.
Key points for communication and inquiry:
When inquiring about prices from suppliers, clearly request: "Please provide quotations and test reports for both PU sandwich panels and PIR sandwich panels that meet the Chinese GB 8624 B1 standard."
Always verify third-party fire resistance test reports for the materials; do not rely solely on verbal claims.