Wossis Ø?

Discussion in 'Water and Waste' started by Kermavio, Jan 18, 2018.

  1. Kermavio

    Kermavio Well-Known Member

    Does this symbol Ø mean inside diameter or outside diameter? I didn't realise how confusing plumbing could be with some suppliers quoting inside diameters, some outside diameters, some with the symbol and others leaving you to guess. Enlightenment please.
  2. time4t

    time4t Well-Known Member

    I believe that's a generic symbol for outside diameter but same as you, not sure.
    Although if describing the inside diameter then the line ends with arrows pointing to the inner wall.
    Pipe is normally described by inside diameter ID, While tube is usually outside OD.

    Kermavio likes this.
  3. misterg

    misterg Well-Known Member

    Just generic diameter symbol, I think: neither ID nor OD specifically.

    As above, hose usually sized by ID, tube by OD and threaded fittings by nominal bore (which may not bear much resemblance to anything measurable!)

    What’s the context?
    Kermavio likes this.
  4. Kermavio

    Kermavio Well-Known Member

    Just general hoses, tank connectors, T's, elbows, etc for the van. For instance, most sink and shower wastes seem to be 25mm. But trying to find some flexi hose / pipe / tube to go on the end of 'em is very confusing. Some sellers say 25mm and then down in the small bits at the bottom, there's a note saying OD. Others say Ø25, whilst others just say 25mm without anything else. And lets not start on 1"!

    I have found one who said 25mm ID - 5.25€ m. At that price, he can keep it.:hushedface:

    To be fair, I've sorted out most of the stuff I need (12mm, 13mm, 1/2" for the water pipes was fun), but I just wondered what that symbol meant and if it was the magic key to the understanding of the secret sizing of plumbers.
  5. Darcar

    Darcar Well-Known Member

    I always find it best to stick with the same manufacturer, that way it doesn’t matter!
    I find John guest quick fit plumbing very reliable & easy to use.
  6. Kermavio

    Kermavio Well-Known Member

    This is a good case in point. All John Guest stuff (for the fresh water) was 12mm OD. My pump and tank connectors are 12mm ID. It's just so confusing. So, providing it fits, I don't care if it's held together by push fit, jubilee clip or string and chewing gum. I just want a bit of consistancy (boring old f**t wot I is).
    Darcar likes this.
  7. Pugwash

    Pugwash Well-Known Member

    They will only be referring to the important diameter. For example, pipes that go into fittings will specify the outside diameter of the pipe, as the inside diameter is not important.
  8. Kermavio

    Kermavio Well-Known Member

    Important for who, Jeff? Not the customer who hasn't any idea that this seemingly random system even exists. I grant if you buy all the stuff from the same manufacturer (possible reason?) then you'll probably get consistancy. But how are you supposed to know? Take my example of the fresh water pipes above. Red and blue food quality hose; pictures of coils looking very similar and described as 12mm (or 13mm or 1/2"). Only when you read down do you discover that some is I/D, some O/D and others with no further information.

    I've been having fun and games with the waste water system, too. My sink, draining board and basin waste fittings all go into 25mm I/D convoluted hose (stuff from my donor caravan). So I wanted the same size fitting for the new shower. The first waste I bought, which had barbs, so was to go inside a pipe, was described as Ø25mm. Only it wasn't, it was 25.5mm and refused to go into my hoses (yes, heating, washing-up liquid, etc were all tried). OK, a mis-description.

    The return postage was almost the same as the purchase price, so I forgot it and another ordered one described as for 28mm hose. The bit that went into the hose was 20mm O/D. Thick bit of tubing that required. So then I bought a reducer / enlarger. 28 > 20 I/D. Only it wasn't, it was O/D!!

    So today I filed down the first waste I bought, glued it into the convoluted hose and jammed a jubilee clip round it:mad:.

    If the whole thing was standardised, there wouldn't be mis-description, confusion or frustration. Or waste of money!
  9. stevetheplumber

    stevetheplumber Well-Known Member

    for water theres basically two systems in motorhomes 12mm push fit and 13mm barbbed hoses the type that use jubilee clips nowdays i would opt for the 12mm pushfit but i wouldnt buy the over priced clear with red and blue stripes from a motorhome dealer just buy the grey or white domestic stuff
  10. Darcar

    Darcar Well-Known Member

    I use standard 15 mm stuff throughout.
  11. misterg

    misterg Well-Known Member

    I've not been able to find much in the way of 12mm push-fit stuff outside of caravan/motor home suppliers - Am I just not looking hard enough?10mm seems common enough though, but dearer than 15mm.

    I think that by the time I've bought the adaptors for everything and a roll of push-fit pipe that it'll be cheaper just to use 1/2" hose on the barbs.
  12. Pugwash

    Pugwash Well-Known Member

    Just as an example, look at a cup holder. You only need the inside diameter of the holder to exceed the outside diameter of the cup. Anything else, like the inside diameter of the cup is unimportant.
    If a pipe fits a barbed connector, the inside diameter fits over the barbs so is important. If the pipe fits inside a push-fit joint, only the outside diameter of the pipe matters.

    I struggled with this a few years back, then assumed the plumbing industry had settled on some standards and re-fitted my bathroom and kitchen.

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