Vijay Posted October 27, 2017 Share Posted October 27, 2017 When using 32mm MDPE compression fittings, why do you need a pipe sleeve with some and not others? Cheers Vijay Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 28, 2017 Share Posted October 28, 2017 15 hours ago, Vijay said: When using 32mm MDPE compression fittings, why do you need a pipe sleeve with some and not others? Cheers Vijay Easier if you post links / examples of the fittings so we can comment Link to comment Share on other sites More sharing options...
Vijay Posted October 28, 2017 Author Share Posted October 28, 2017 (edited) This one needs a pipe liner https://www.waterirrigation.co.uk/plasson-silverline-straight-compression-coupling-32mm-x-32mm.html where the likes of these have no mention of needing a pipe liner https://www.toolstation.com/shop/Plumbing/d20/MDPE+Pipe+%26+Fittings/sd2729/MDPE+Straight+Coupling/p59371 or https://www.screwfix.com/p/floplast-493012-mdpe-coupler-32mm-x-32mm/1532f Edited October 28, 2017 by Vijay Link to comment Share on other sites More sharing options...
PeterW Posted October 28, 2017 Share Posted October 28, 2017 Most need inserts - the Floplast ones definitely do. Dont use a catalogue description as the fitting instructions .... 1 Link to comment Share on other sites More sharing options...
Vijay Posted October 28, 2017 Author Share Posted October 28, 2017 I thought the purpose of inserts were to stop the fitting from crushing the pipe when using olives? Seeing as these rely on rubber O rings to form the seal, do they still compress that much that they would crush the pipe?? Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 28, 2017 Share Posted October 28, 2017 https://www.screwfix.com/p/floplast-mdpe-pipe-inserts-25mm-10-pack/14371 On this link click more info then q's & a's ? https://www.screwfix.com/p/floplast-mdpe-pipe-inserts-25mm-10-pack/14371#product_additional_details_container Inserts are required, as said, an item description is just that . Link to comment Share on other sites More sharing options...
Vijay Posted October 28, 2017 Author Share Posted October 28, 2017 It's 32mm I'm using, but is it standard practice to use pipe inserts with all MDPE pipe/fittings then?? Link to comment Share on other sites More sharing options...
jamiehamy Posted October 28, 2017 Share Posted October 28, 2017 I would say so. When you tighten the connection there is a form of clamping occurs I to the pipe which is most likely why the insert is still needed. The rubber ring seals but there is a 'thing' that clamps onto the pipe and bites i. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 28, 2017 Share Posted October 28, 2017 32 minutes ago, jamiehamy said: I would say so. When you tighten the connection there is a form of clamping occurs I to the pipe which is most likely why the insert is still needed. The rubber ring seals but there is a 'thing' that clamps onto the pipe and bites i. +1 Link to comment Share on other sites More sharing options...
Dyfed Posted October 28, 2017 Share Posted October 28, 2017 Hi, i am a plumbing and heating engineer by trade, and on here as I am hoping to do a self build next year! as like all the other comments you deffinetley need to use inserts with all types of fittings! The manufacturer will no warranty any potential failiours if they find that you have fitted them without inserts and you also need to ensure you use an appropriate plastic cutter and not a hacksaw! Link to comment Share on other sites More sharing options...
Jeremy Harris Posted October 28, 2017 Share Posted October 28, 2017 (edited) 9 hours ago, Vijay said: I thought the purpose of inserts were to stop the fitting from crushing the pipe when using olives? Seeing as these rely on rubber O rings to form the seal, do they still compress that much that they would crush the pipe?? The inserts have two functions, and are, as mentioned above, essential. They do provide a bit of additional stiffening, not for the area where the O ring or lip seal bears, but the bit further up where the grip ring bites into the pipe to hold it in place. The other reason they are essential is that they provide a smooth entry when pushing the pipe in, because there is a chamfer on the flange part of the insert, preventing the sharp cut edge of the pipe from damaging the O ring or lip seal. Edited October 28, 2017 by JSHarris Link to comment Share on other sites More sharing options...
Bitpipe Posted October 29, 2017 Share Posted October 29, 2017 Hmm, I omitted these when building my rainwater tanks - doesn't seem to leaking but I'll retro fit none the less - do I need to scrap the 32mm MPDE pipe I've already used and start again? I've plenty of it so no hardship... Link to comment Share on other sites More sharing options...
Jeremy Harris Posted October 29, 2017 Share Posted October 29, 2017 1 minute ago, Bitpipe said: Hmm, I omitted these when building my rainwater tanks - doesn't seem to leaking but I'll retro fit none the less - do I need to scrap the 32mm MPDE pipe I've already used and start again? I've plenty of it so no hardship... The pipe's probably fine, the most likely issue when not using the inserts on low pressure pipe work, where the fitting hasn't been over-tightened, is that the seals can be damaged, as the insert has a smooth chamfer on the flange that covers the cut end of the pipe, to help ease the pipe into either the O ring or lip seal (some MDPE fitting use O rings, some use lip seals). My experience is that it's quite hard to damage these seals, unless the cut end of the pipe is rough (which is why you shouldn't just hack through it with a saw, but use a proper pipe cutter, which has a very sharp blade). Link to comment Share on other sites More sharing options...
PeterW Posted October 29, 2017 Share Posted October 29, 2017 Nope the pipe should be fine - slack off and pull the joint apart, put the insert into the pipe and do it all back up. Be aware though that some of the joints won’t come apart easily unless you remove the outer nut and take it completely apart. As you have very little pressure as it’s just the static pressure of 1m of water. . Link to comment Share on other sites More sharing options...
Vijay Posted October 29, 2017 Author Share Posted October 29, 2017 Thank everyone for the explanations, will definitely get inserts then Or are the pushfit fittings any good? https://www.toolstation.com/shop/p96079?table=no Link to comment Share on other sites More sharing options...
PeterW Posted October 29, 2017 Share Posted October 29, 2017 I may be old fashioned but for stuff buried in the ground I only use decent brands - I use Plasson for all that stuff. Pipestock do it all at decent prices. https://www.pipestock.com/plasson/mechanical-fittings/coupling 1 Link to comment Share on other sites More sharing options...
Vijay Posted October 29, 2017 Author Share Posted October 29, 2017 (edited) that's probably a very wise move Edited October 29, 2017 by Vijay Link to comment Share on other sites More sharing options...
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