ToughButterCup Posted January 24, 2020 Share Posted January 24, 2020 The following overheard at a local plumbing depot: a real proper plumbers merchant, smelling of paraffin, sweat, linseed and thinners - Single lightbulb on at the hatch where sits a Ditsy Teeny Blond Bomshell : her nail varnish bottle out on the counter: cotton wool blob and nail file and thinners bottle open - slightly heady scent. One hand waving to and fro to dry the nail she had absent-mindedly painted a few seconds ago. A local plumber beats me to the counter: smiles at the lass who's now on her second nail of the day .... Y' awreet mert? she says sweetly, while looking at nail number three Aye 'Appen ye've sum 3/4 irons in then? Wadja mean 22 mill? Nahh, I need sum three quarters Pause: by now nail number three had a wet edge, and so needed constant attention We've got sum inch in if that'd do ya? Nahh, I need three quarters really. Ditsy promtly turns and shouts to some hidden Golum deep in the bowels of the warehouse. I cant pretend to remember what she said because I didn't understand it. I speak four languages, and Plumber isn't one of them. Golum replied: which langauge does Golum speak? - because I understood not a word. Not a syllable. The plumber left. My turn. Do you sell HEP2o ? The shock of the question actually stopped her nail painting - eyed me suspiciously. 'S all Speedfit 'ere. And got on with nail number 4 I stood there for a moment and wondered if I should ask her what an inch iron was. Didn't have the guts. I'd feel better if anyone could please point me to a SIMPLE online resource which explains in simple terms the Imperial equivalents of 10, 15, 22 and 25mm piping is please. There are so many Metric to Imperial charts that do nothing more than complicate the problem ( to me anyway) Oh, and what's a plumbing iron in English ? 2 Link to comment Share on other sites More sharing options...
Temp Posted January 24, 2020 Share Posted January 24, 2020 (edited) I would suggest it's not possible to produce a simple guide! In some cases the actual diameter of a pipe is manufacture specific. So for example 50mm waste pipe isn't 50mm in diameter, it's exact size sometimes depends on the make and if it's push fit or solvent weld. For that reason size conversion charts should only be used to get you in the right ball park. Stick to one make and keep receipts is best advice I can give. Edited January 24, 2020 by Temp Link to comment Share on other sites More sharing options...
SteamyTea Posted January 24, 2020 Share Posted January 24, 2020 I walked out of a shop after the sales assistance tried to not discount an item on sale. I even bothered to call up the head office, not as a complaint as such, more to point out the hopeless and confusing pricing policy. The person the phone actually agreed with me. Probably a temp. 1 Link to comment Share on other sites More sharing options...
ToughButterCup Posted January 24, 2020 Author Share Posted January 24, 2020 27 minutes ago, Temp said: ... For that reason size conversion charts should only be used to get you in the right ball park. Stick to one make and keep receipts is best advice I can give. It's not just me then That's a relief Link to comment Share on other sites More sharing options...
Danny68 Posted January 24, 2020 Share Posted January 24, 2020 Back in another life as a plumber I used Jacob's plumbers on Grays inn Rd proper plumbers with the obligatory cellar from which any plumbing fitting ever produced would be stored . The guy behind the ramp would write your order in b.s numbers . Wasnt long before the humble float and ball valve would be referred to as a 12-12 . 1 Link to comment Share on other sites More sharing options...
ProDave Posted January 24, 2020 Share Posted January 24, 2020 I gave up trying to understand plumbing measurements when I discovered "40mm" waste pipe is not 40mm diameter either inside or out, and that solvent weld and compression "40mm" waste pipe are different sizes. You get a better result taking a fitting and saying "I want pipe to fit that please" Link to comment Share on other sites More sharing options...
Jeremy Harris Posted January 24, 2020 Share Posted January 24, 2020 3 minutes ago, ProDave said: I gave up trying to understand plumbing measurements when I discovered "40mm" waste pipe is not 40mm diameter either inside or out, and that solvent weld and compression "40mm" waste pipe are different sizes. You get a better result taking a fitting and saying "I want pipe to fit that please" Just measured a bit of "50mm" Floplast waste pipe. It's actually marked with the dimensions on the side, "55mm x 2mm". A quick check showed that it's really 55mm OD and 51mm ID. Bit like OpenReach Duct 56, which is really 54mm OD and 50mm ID. All these dimensions seem to be randomly chosen, with no rhyme nor reason as to why a particular pipe is given a particular dimension as a name. 1 Link to comment Share on other sites More sharing options...
ProDave Posted January 24, 2020 Share Posted January 24, 2020 7 minutes ago, Jeremy Harris said: Just measured a bit of "50mm" Floplast waste pipe. It's actually marked with the dimensions on the side, "55mm x 2mm". A quick check showed that it's really 55mm OD and 51mm ID. Bit like OpenReach Duct 56, which is really 54mm OD and 50mm ID. All these dimensions seem to be randomly chosen, with no rhyme nor reason as to why a particular pipe is given a particular dimension as a name. I had an argument with an ebay seller when I bought a 110mm to 50mm waste pipe reducer. What turned up was indeed a reducer from 110mm to 50mm. Only trouble was it really was for 50mm OD pipe and there was no way the 54mm diameter UK "50mm" waste pipe would fit. I can't understand how he could sell that in the UK as surely everyone that bought one would return it becase you cannot buy the pipe to fit it. Link to comment Share on other sites More sharing options...
joe90 Posted January 24, 2020 Share Posted January 24, 2020 1 minute ago, ProDave said: I had an argument with an ebay seller when I bought a 110mm to 50mm waste pipe reducer. What turned up was indeed a reducer from 110mm to 50mm. Only trouble was it really was for 50mm OD pipe and there was no way the 54mm diameter UK "50mm" waste pipe would fit. I can't understand how he could sell that in the UK as surely everyone that bought one would return it becase you cannot buy the pipe to fit it. but his description was correct!!! If he said 50mm pushfit or solvent Weld you may have a leg to stand on. I had the same trouble with plastic overflow pipe years ago, now I buy the same make pipe and fittings. Link to comment Share on other sites More sharing options...
Temp Posted January 24, 2020 Share Posted January 24, 2020 This page summarises what's been said above.. https://job-prices.co.uk/waste-pipe-dimensions/ 1 Link to comment Share on other sites More sharing options...
Construction Channel Posted January 24, 2020 Share Posted January 24, 2020 3 hours ago, AnonymousBosch said: Oh, and what's a plumbing iron in English 28mm x 1" Male Iron Straight Compression WRAS Approved Heavy Pattern Embrass https://www.amazon.co.uk/dp/B07QD9X8SJ/ref=cm_sw_r_cp_apa_i_KOXkEbNB5GKTH I had to buy a few for my system, I think the inch part is referring to the thread size but I really don't know, I just bought what the plumber told me to Link to comment Share on other sites More sharing options...
Construction Channel Posted January 24, 2020 Share Posted January 24, 2020 Also I don't think you can mix metric and imperial without converters, 22mm pipe would be the metric version of a 3/4 pipe. (I assume the ID would be close to 19mm ish), 15mm would be 1/2inch and so on. At least that's my understanding of it. One thing I learnt doing mine was the merchant will always tell you the simple fitting you want isn't made by anyone and you will need to use between 2 and 7 alternative fittings to achieve the simple task. But as long as you can find out what to search for someone on the Internet will sell the simple fitting you need Link to comment Share on other sites More sharing options...
Gone West Posted January 24, 2020 Share Posted January 24, 2020 This might help. Pipe Sizes and Dimensions Chart.doc 1 Link to comment Share on other sites More sharing options...
Oz07 Posted January 25, 2020 Share Posted January 25, 2020 My manifolds needed irons 25mm to 22mm compression for heating 3/4 to 22mm compression for water. You just have to go with whatever is on what you're connecting to Link to comment Share on other sites More sharing options...
ToughButterCup Posted January 25, 2020 Author Share Posted January 25, 2020 What a glorious mess. That's what a German Anglophile loves about the UK. It's interesting, full of quirks not boring, or standardised like the Teutons. 1 Link to comment Share on other sites More sharing options...
dpmiller Posted January 25, 2020 Share Posted January 25, 2020 lucky you're not in the RoI then, where modern MLCP pipes are still used in true imperial sizes... They're a kinda copper-coloured creamy brown... Link to comment Share on other sites More sharing options...
ProDave Posted January 25, 2020 Share Posted January 25, 2020 Ah, now we have mentioned imperial fittings, I await someone telling me exactly what dimension of a 1/2" BSP thread actually measures half an inch, as I can't find one. Link to comment Share on other sites More sharing options...
PeterW Posted January 25, 2020 Share Posted January 25, 2020 19 minutes ago, ProDave said: Ah, now we have mentioned imperial fittings, I await someone telling me exactly what dimension of a 1/2" BSP thread actually measures half an inch, as I can't find one. It isn’t ... a BSP thread is the outer diameter of the threads minus 1/4”... The 1/2” used to refer to the steel pipe size it would fit but that has changed due to different wall thicknesses etc over time. Link to comment Share on other sites More sharing options...
dpmiller Posted January 25, 2020 Share Posted January 25, 2020 nominal bore of a black-iron pipe of that size IIRC? Link to comment Share on other sites More sharing options...
PeterW Posted January 25, 2020 Share Posted January 25, 2020 2 minutes ago, dpmiller said: nominal bore of a black-iron pipe of that size IIRC? Yep but wall thickness has changed so now it doesn’t match Link to comment Share on other sites More sharing options...
billt Posted January 25, 2020 Share Posted January 25, 2020 1 hour ago, AnonymousBosch said: What a glorious mess. That's what a German Anglophile loves about the UK. It's interesting, full of quirks not boring, or standardised like the Teutons. But German pipe threads are exactly the same as British ones, but with a different name, apparently. https://www.harveywatersofteners.co.uk/blog/plumbers-pipes-and-german-vs-english-standards "What most people do not appreciate is that Whitworth invented the standardised thread-form back in 1841 and the British Empire spread this around the world. When they decided on a standard thread for plumbing pipework, the British Standard Pipe Thread, it was the Whitworth thread-form that was adopted. This also spread around the world and virtually every continent uses this system. However, there are two anomalies. The German’s didn’t like the idea of recognising the English BSP so they called their system DIN. It is in fact exactly the same thread-form as Whitworth so to identify the correct thread size under the DIN Standard, you have DIN 15 equalling BSP half inch. DIN 20 equalling BSP three quarter inch and DIN 25 equalling BSP one inch. Our dear friends the Americans went one better and they called their system NPT, National Pipe Thread. Just as they changed the size of the Imperial gallon to the US gallon, they changed the thread-form from Whitworth to something entirely different. So instead of having the Standard 55 degree angle on the threads, they changed it to 60. (Yes you have to ask yourself why?). The net result is that whereas the DIN pipe threads are interchangeable with BSP pipe threads, the American NPT pipe threads are not. You can graunch a half inch NPT into a half inch BSP fitting and the sealant will take up the slack." 2 Link to comment Share on other sites More sharing options...
PeterW Posted January 25, 2020 Share Posted January 25, 2020 (edited) The difference between BSP and BPT is also the thread angle of 55 to 60 degrees which adds to the confusion .... Edited January 25, 2020 by PeterW Typo Link to comment Share on other sites More sharing options...
SteamyTea Posted January 25, 2020 Share Posted January 25, 2020 54 minutes ago, PeterW said: The difference between BSP and BPT is also the thread angle of 55 to 60 degrees which adds to the confusion How about tapered threads. We laugh about the French not being able to agree on anything because they have over 360 different cheeses. Link to comment Share on other sites More sharing options...
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