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      Polyurethane Foam/ Aluminum Foil Composite Board
Conventional Ducting Huayu PU/AL Board Advantages Comparisons between various type of ducts Recommended Applications Background of Huayu


Conventional Duct work and Insulation process

1.  Installation of zinc coated galvanized sheet metal ducts , normally pre-fabricated in factory , with hangers and supports .

2. Insulation of bare metal duct with rock wool or fiberglass boards .  Work is done on site

3. Aluminum foil -wax  coated sheet is wrapped outside  the insulation as vapor barrier  . Work is done on site

4. Installation of  vibration   and acoustic lining and dampers wherever necessary

5.  Problem of proper insulation and sealing through walls

6.  It is very time consuming and labor intensive




Problems with Conventional Ducting/insulation

1.  Time consuming and costly in doing a proper ducting and insulation work .

2.  Poor Acoustic damping property

3.  Sheet metal ducting system is heavy and it needs extensive hangers supports , all adds load to building .

4.  Ducting system exterior aesthetically not pleasing . It needs to be concealed behind false ceiling , results in less usable space and less head room.

5.  Air leakage and condensation are the major problems that needs regular maintenance . It affects the insulation property , higher cooling/heating load and conceals health problem due to fungus growing in the ducting system .

6.  Short life , normally between 7 to 10 years .



Huayu PU/AL  Composite Board







20 mm thick CFC-free high density polyurethane foam sandwiched in between aluminum foil laminations on both sides . Structurally strong and dimensionally rigid to form air ducts of any common configurations without the need of inner metal duct support .  Entire PU/AL composite ducting can be fabricated on site and the total installation time is much shorter than the conventional ducting system .   

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  • PU/AL Composite Ducting is a complete 3 in 1  ducting system combines duct structure , insulation and vapor barrier functions.
  • Superior insulation property of CFC-free PU foam results in significant energy saving in its entire life .
  • It does not leak air or absorb water and has no condensation problem
  • It requires less labor-hour to fabricate and install.  Entire process can be done on site The work speed is as much as 10 times the conventional ducting .
  • The life span is 2 time longer than conventional ducting with minimum maintenance in between .
  • It has excellent acoustic and vibration damping properties , as well as flame retardant property
  • The duct weight is 1/10 of normal metal ductwork . It requires less hangers and support , a significant saving .
  • It gives more head room .  Duct exterior is aesthetically pleasing . False ceiling may not be needed .
  • The overall savings on building cost due to lighter ducting weight ,  more usable headroom , time saving in installation , lower running cost of the cooling/heating system . 


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Comparison between 3 composite ducting PU/AL , PH/Al  , XPS/AL


Performance PU/AL Duct Phenolic/AL Duct XPS/AL Duct
Insulation Performance A B C+
Flame Retardation B A C+
Secondary pollution free A C A
Noise suppression A B B
Adhesion strength between foam and foil surface A C C
Exterior impression A A A


  Composite type ducting , consists of foam made of Polyurethane , Phenolic and Expanded Polystyrene , sandwiched between 2 layers of aluminum Foils .

Left table shows the difference between 3 composite type insulated ducts .  Polyurethane foam type has clear advantages over the other two in terms of insulation property , life span , adhesion between foam and foil , noise suppression and virtually no secondary pollution during use . The fire resistant rating is slight lower than Phenolic type board but is better than XPS .

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Comparison between Composite type ducts and conventional ducts

  PU/AL Duct Sheet Metal Duct System with Fiberglass Insulation Phenolic/AL Duct XPS/AL Duct Fiberglass Conduit
Heat Conductivity

 λ  W/M K



( 0.146 Btu in. / ft. hour F )

0.045 0.028 0.03 0.045
Weight  kg/m2 1.3 to 1.4 ( 20 mm T ) less hangers and support needed 8.2 Heavy , needs many hangers and support, floor loading is high 1.3 to 1.4(20mm T)less hangers and support needed 1.1 to 1.3( 20mm T)less hangers and support needed 8.8 Heavy (4mm) floor loading is high
Fire Resistant B1 A B1 poor A
Life Span No rust , corrosion free , up to 20 years life Rust and corrode easily , 5 to 7 years Poor adhesion between foam and foil , 15 years Poor adhesion between foam and foil , 15 - 20 years No rust or corrosion , but suffer from crack problem 10 to 15 years
Secondary Pollution Almost none Fiber fray and loose Poor join Little Fiber Fray problem
Installation Easy , fast and maximum use of space. no false ceiling needed Difficult to install . take long time to install , false ceiling is needed , poor use of space Easy , fast and maximum use of space. no false ceiling needed Easy , fast and maximum use of space. no false ceiling needed Difficult to install and takes long time . false ceiling may be needed . Space usage is not as good
Cost index 1.05 to 1.1 1 1.05 to 1.1 1 to 1.05 0.9 - 0.95

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Airport  terminals



Subway Station


Pu/Al composite board ducting is recommended for central air con system in bus/train stations , hospitals, supermarkets , commercial buildings , holiday resorts , hotels and airports etc .



Back ground of Huayu





LangFang Huayu Innovation Science and Technology Co. Ltd is located at Beijing LangFang Economic Development District , center of eastern China BuHai economic development sphere   . It occupies 50 acres of land built for R&D and manufacturing activities of insulation foam boards  ( Polyurethane and Phenolic foam ) . All staff are highly trained professions in material and foam application technology . Huayu owns several IP rights in CFC-Free PU compounding technology  . The composite foam is produced by a fully automated line imported from Europe .

It is a offshoot of Lanzhou Huayu Aerospace Materials Ltd , subsidiary of CASC ,  and China Environmental Protection Agency .

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