Pre-insulated duct board materials

In the heating, Ventilation and Air Conditioning (HVAC) system, air ducting is playing an important role. Several factors and recent innovation have introduced the need to revolutionize air ducting. The pre-insulated system is a proven, easy, innovative product. It virtually eliminated all the problems of traditional metal duct work. Good features of pre-insulated ducts are as following:

* Low thermal conductivity. The thermal conductivity can be as low as 0.024W/mk, which saves a lot of electricity costs.

* Suitable for many HVAC system for its good flame retardant properties. 

* Saving installation costs. The installation cost of pre-insulated ducts is 10% lower than traditional sheet metal ducts.

* Lower weight. The weight of pre-insulated ducts is light weight and easy to handle. Thus, fewer people is needed to install the ducts.

* The duct board is strong and can withstand a pressure of 0.25Mpa and bending force of 2Mpa.

Pre-insulated duct materials

1. Phenolic duct

Phenolic duct is one kind of Pre-insulated Duct Panel, which is made of phenolic insulation foam, and aluminum foil/galvanized iron sheet on both sides. Phenolic duct panels are widely used in HVAC systems. It is a energy saving, environment-friendly, and fireproof material. And it is tested as the best thermal property. For internal use, Phenolic panel with both sides embossed 80mm is recommended. For external use, it’s recommended to use 200mm aluminum foil or GI sheet surface. Because it has better bending strength and compressive strength.

The thermal conductivity of phenolic foam is about 0.025w/(m.k) to 0.35w/(m.k), which is better than that of rubber, plastic and glass wool materials. Good thermal insulation performance avoids the condensation problem of the air duct. In addition, the unique connection method of the phenolic composite air duct ensures the excellent air tightness of the ventilation system, which is nearly 8 times that of the galvanized steel air duct. Its heat dissipation loss is much less than other ducts.

Heat dissipation loss

* Galvanized steel duct: 15%

* Fiber glass duct: 8%

* Phenolic duct: less than 2%

2. PU Duct

Pu duct is a kind of pre-insulated material that consists of polyurethane (PU) insulation foam and aluminum foil/galvanized iron sheet on both sides. The outer layer of the polyurethane air duct is made of high-purity thin aluminum plate, and the middle layer is made of flame-retardant rigid polyurethane foam, which has high strength, B1-level flame-retardant and fire-proof, waterproof and moisture-proof, no pollution, and stable performance.

3. PIR Duct

PIR Pre-insulated Duct Panel is made of polyisocyanurate (PIR) insulation foam. It often comes with aluminum foil / galvanized iron (GI) sheet on both sides. PIR is a rigid foam insulation material made of isocyanate reacted with polyether after catalyst. It has good flame retardant performance, particularly low thermal conductivity and good dimensional stability. It is suitable for thermal insulation of industrial pipes and equipment in the temperature range of -196 °C to +120 °C, as well as heating and ventilation pipes, building walls, ship insulation, etc. field.

Compared with the phenolic duct, PIR duct has the advantages of environmental protection, stable physical properties, good strength, no dust, no peeling, no slag, and long service life.

Compared with the PU duct, PIR duct has better fire resistance. During ablation, a dense carbonized layer can be formed on the surface of the PIR, which can effectively hinder the continuous burning of the foam plastic, and has little irritation and smoke. When the polyurethane is burned, there will be a dripping phenomenon, a large amount of irritating gas will be released, and the amount of smoke will be large.

Pre-insulated duct fabrication

Traditional way of pre-insulated duct fabrication is normally done by tracing, manual cutting, gluing, folding, taping, flanging&reinforcement and sealing. Before a PID duct board cutting machine was launched in the market, duct fabricators normally do manual cutting. They spend lots of time to do design, layout, measuring, and cutting. But since the PID board cutting machine launched, it has become a hit in the market. PID board cutting machine is a type of CNC duct fabrication machine. PID board cutting machine always comes with a software which helps you do the layouts and measurements on the duct boards. There are many types of PID board cutting machines in the market. Please do more research before you purchase a PID board cutting machine. Because many of the PID board cutting machines are CNC routers which generate much dusts and noise. A suitable PID board cutting machine will definitely save you lots of time and money! 

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