Differences in 75mm semi-rigid ducting?

[MJNewton]

By all accounts it seems that dimensionally all 75mm OD semi-rigid ducting is equivalent (or close enough perhaps?) and that mixing components from different manufacturers is therefore possible but does anyone know if there are any other differences in materials, quality etc of the pipes? What made me wonder is that one well-known supplier sells both Domus and Airflow ducting and the price for a 50m roll of each is £142 and £168 respectively. Perhaps it can just be explained by variations in the supply chain and other retail issues?

 

I was going to ask said supplier but they are closed over the weekend and I can't seem to settle with unanswered questions hanging over me! ?

[Dudda]

You can get 75mm inner diameter which is 92mm outer diameter and you can get cheaper ducts advertising as 75mm but it's outer with 63mm I think. The bigger is better for airflow.

Usually that difference in size is more than £26 though so might be just difference in quality.

[PeterW]

10 hours ago, MJNewton said:

By all accounts it seems that dimensionally all 75mm OD semi-rigid ducting is equivalent (or close enough perhaps?) and that mixing components from different manufacturers is therefore possible 

 

The two or three samples I had were virtually identical as they probably came off the same production line. Twinwall extrusion of polyethylene isn’t that complex but does need a different type of machine head so it’s limited to a  few manufacturers.

 

The only difference seemed to be in the external corrugation profile, with one being slightly squarer in profile than the other but this wouldn’t affect anything I can see. 

 

In terms of hygiene and “anti static” coatings, the Inner surface on this type of duct is virtually sterile when produced but the looping mechanism induces some amount of static due to the nature of the product so dust will be attracted to the inner surfaces. From what I can work out, some suppliers use an anti static coating which is just a silicone based spray - just as quick to do your own and use a pompom on a bit of string as per @JSHarris and coat it in any of the silicone furniture polishes. 

[Jeremy Harris]

My understanding is that the 63mm ID, 75mm OD duct was originally designed by HB+ and then licenced to several manufacturers, who in turn have marketed it under many different brand names.  It's made more complex by the fact that some suppliers give this ducting their own name.  Back when I first looked at using it there were only two UK versions being offered, Domus (originally a PolyPipe brand) and HB+, but now there seem to be lots of suppliers offering the same, or very similar, stuff.

[MJNewton]

Thanks everyone. I think I may as well go for the cheaper of the two (Domus)... 'Look after the pennies...' and all that!

[Nickfromwales]

Party over. Bye bye mark