PIR Insulation Sheet

Many people simply understand PIR as a "fire-resistant improved version of PU". Essentially, it is two completely different polymer systems. PU relies on amine carbamate bonds, while PIR has an isocyanurate ring as its main framework. The thermal decomposition temperature of this cyclic bond is much higher than that of ordinary amine carbamate bonds. At high temperatures, it will not melt and flow rapidly, and when burning, a dense carbonized layer is formed on the surface, blocking the spread of flames inward and inhibiting the release of thick smoke, achieving the B1 fire-resistant effect. While ordinary PU can mostly only achieve B2 level.

At the same time, the 95%+ closed-cell structure allows gases to be locked inside the foam cells, achieving extremely low thermal conductivity. Without having to use extremely thick boards, a higher thermal resistance can be achieved. This is the fundamental reason why PIR boards can be made thin while maintaining the same level of insulation effect. However, the synthesis of this molecule is extremely sensitive to the formula ratio and reaction temperature.

The PIR sheet material itself has excellent performance, but improper on-site construction can directly ruin the product's performance. When cutting, if an ordinary utility knife is used, it will compress and damage the closed-cell structure of the cut, turning the cut into a water absorption channel. After water vapor seeps in, the local thermal conductivity will soar. The correct approach is to use a fine-tooth saw or a heat wire cutter to ensure the integrity of the cut cell structure.

Secondly, the aluminum foil surface layer is extremely prone to scratches. Once damaged, water vapor can directly enter the core material. Therefore, protective measures for the surface layer need to be taken during handling and laying. Additionally, the direction of the vapor barrier layer cannot be reversed. Incorrect laying will form a water vapor trap, causing continuous moisture accumulation inside the sheet and resulting in bulging and delamination over the long term. Many project failures are not due to product quality defects, but rather the loss of control over the detailed on-site processes.

Step 1 - Tracing: outline the duct shapes on the panel.

Step 2 - Cutting: Using manual cutting tools, cut along the panel edges and create 90 degree "V" grooves on the panel.

Step 3 - Gluing: Apply glue to the cutting surfaces of the panels.

Step 4 - Folding: After the glue is cured, fold the sides toward each other to form the straight duct.

Step 5 - Taping: The tape is applied only to the external seams of the duct where the sides of the panel were joined for air-tightness.

Step 6 - Flanging: After applying glue and positioning the steel angle bracket, process to fit the PVC or aluminum invisible flanges.

Step 7 - Reinforcement: reinforce the duct with an aluminum reinforcement bar and G.I. Shaped disks, if necessary.

Step 8 - Sealing: After the duct is assembled, seal all internal joints hermetically with silicone.

Need the complete fabrication solution?

UNT Duct supplies PIR duct panels, fabrication tools, jointing accessories, reinforcement components and related materials for complete pre-insulated duct fabrication.