Plastic Ducting uses

Plastic ducting is usually made out of either pvc-u (unplasticised polyvinyl chloride) or polypropylene. Pressure pipe has a much thicker wall and is far heavier than ventilation or ducting pipework, which has a much thinner wall and is subject to different standards and ratings.

Plastic ducting is not suitable for use with liquids or solids such as granular materials as it does not have sufficient strength to prevent distortion and breakage. The main use for this pipe is in the fume extraction and ventilation industries where it is used to carry gasses such as air or contaminated air.
The choice of materials used for ducting is dependent on the application. PVC ducting is the cheapest to buy, systems are easier to construct through a solvent weld method and it is available in a larger number of fittings.  PVC does however have its limitations: it is restricted to a maximum operating temperature of 50 degrees centigrade and because the plastic begins to increasingly soften with temperature, it requires more frequent supporting as the temperature increases. The properties of pvc, namely the fact that it is very easy to bond to, makes it subject to contamination and so unsuitable for some clean room applications such as the food industry. The molecular structure of PPS Polypropylene on the other hand is a very different and is such that other compounds find it very difficult to adhere to it. This makes it the plastic of choice for clean room applications. Polypropylene ventilation systems can however build up a significant amount of static, which can lead to the attraction and build-up of dust and other charged particles. For situations where ultra clean and antistatic pipework is important, such as in the semiconductor industry, PPS ducting is available in a special antistatic form. This is the most expensive of all types of plastic ducting.

Where pvc pipe is solvent welded together, polypropylene should, for permanent installations, be heat welded. Some users prefer not to heat weld and after adding in extra supports, use a silicone or other type of sealant to bond fittings together. This may be suitable for some applications, but care needs to be taken that the system is properly supported and siliconed joins do not impart any strength. Silicone is also easy to bond to and so if used as part of the assembly process, may compromise the suitability of the system.

Plastic ducting, especially pvc, often finds uses I other industry sectors. The film and media sectors use it to create false columns, where it is painted or has material glued to it – for trees etc. The lightweight nature of the pipe makes it easy handle and to move around sets. Smaller bore ducting is sometimes used as cable duct, where the smooth inner surface makes it easy to pull multiple cables through long distances. It also finds a use as protective packaging for expensive machine parts, and when mounted vertically, the manufacture of small plastic water and chemical tanks and air and water filtration systems.
The main manufacturer of plastic ducting in Europe is HOKA, a company based in Germany. The UK distributor for their ducting products are Pisces Pipe Systems.
In summary, plastic ducting is a versatile component that has many uses, other than straight forward ventilation works.