Cold and Hot water pipe sizing to BS EN 806 Part 3 'Pipe Sizing Simplified method'
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- čas přidán 4. 08. 2024
- Cold and Hot water pipe sizing to BS EN 806 Part 3 'Pipe Sizing Simplified method'
Objectives
At the end of this session you will gain an understanding of;
Pipe sizing to BS EN 806 part 3,
Key terms, symbols and units,
Maximum flow velocities,
What are Loading units,
Pipe sizing for internal Copper pipes and Plastic pressure pipe,
Pipe sizing for external MDPE pipe.
Scope
This European Standard is in conjunction with EN 806-1 and EN 806-2 for drinking water systems within premises.
This European Standard describes a calculation method for the dimensioning of pipes for the type of drinking water standard installations as defined in 4.2.
It contains no pipe sizing for fire fighting systems.
Very educative, useful and simplified. Thank you.
Sorry was on holiday, Thank you very much.
Very educational video for the basic residential water supply piping system. I hope there will be another video showing the calculation of LU vs the flow and how to adopt it. Thanks for this nice video.
Thank you for your feedback, at this time I am working on the science of plumbing part of this course but I have made a note of this and will get to it for you as soon as I can.
Please do more of these videos! This one is very helpful..Many Thanks
More are coming, I just have to finish teaching my groups. I have just finished an updated gas pipe sizing presentation and will be recording it soon. Thank you for your support.
Thanks for the shared Knowledge :)
Thank you for your support
this is brilliant, thank you
Thank for your support 🙏
please do more we apricate the efforts
I am just fighting with the new 8202 level 3 course at the moment, I have to finish the whole group I am teaching soon. All go to plan I will have more time to make more videos. Thank you for your support.
Very useful. can you do another video considering the friction losses and pipe lengths for selecting water supply pipes? Thanks a lot. nice work though !!!!!!
Hi Eranda,
Yes, I can do that. I am working on one at the moment which should cover what you are asking for. This one is covering the older BS 6700 which BS EN 806 replaced.
HI great video, just a curiosity in 10:57 you have the chart of pipes - isnt push fit pipe polybutylene, shouldn't that chart be used when working out pressure pipe rather than the copper one or does it give the same results? thanks
Hi,
Good question, and yes you are correct but after a number of times working out pipe sizing using them both I came up with the same answer, so now I just use the copper one for both. Plus I didn't want to risk being hit with a copyright showing more of the BS EN 806 part 3, so left it out. If you would like me to, I will be happy once I get time to make another one for polybutylene (PB) and (PEX) I will and I will use the same plans.
Thank you for your question and your support.
Thank you for this, really helpful! If i'm limited by a 15mm cold main coming in. With a similar setup to your video, I'm assuming there wouldn't be any need to go from 15mm to 22mm even if the design recommends it?
Thank you for the feed back.
Sorry for not answers right away. Very busy with exams and assessments.
I would say yes, if this is a completely new install and there is no pipework around the home. It is still good to install it as the design goes, even if you have 15mm coming in. It will still help with all the outlets and an sure you have no problems in the future. I would also see about increasing the incoming main at the same time. But if this is already all installed then I would say leave it as is until you are upgrading the home and fix it all then.
Hope this answers your question.
Hi that’s great thank you for the reply! How does mains pressure, flow rate and pipe length between sections come into this? Is there an assumptions made for these calculations? Thanks again.
Thank you!!
Is there a formula to represent the Loading Unit to Flow Rate relation (Conversion Chart on BRITISH STANDARD BS 6700 : 1997 page - 72) please?
Hi and thank you for your question,
Sorry, I didn’t answer right away, I have been away and not near any of the paperwork.
First off your British is out of date and we are now on BS 6700:2006+A1:2009 but I have an old copy and have found the page you are talking about. In the new Standards, this is on pages 120 and 121. A lot more pages have been added but in this case, the information is the same so all ok.
The loading units used in BS6700 are different from BS EN 806 part 3 as they use different formulas to work out the sizing of the pipework. So sorry there is no formula to represent in relation to loading units and flow rates. They both work and we still use BS 6700 when we are wanting a more precise answer but is very long-winded to complete and you have to use the chart to take the loading units you have worked out for the dwelling. Then mark it onto the chart which then shows you the flow rates that you need for the next part of the equation. With BS EN 806 part 3, they have already done this and cut the formula down, this is why the title is ‘Pipe Sizing Simplified’ on the front of the document.
Hope this answered your question, anything else please feel free to ask.
Very useful. How can we find out required main incoming pressure using this method? Thank you.
To find out the mains pressure you will need a Mains water pressure gauge. The one I use is this www.screwfix.com/p/monument-tools-mains-water-pressure-test-gauge-11bar/82412?kpid=82412&ds_kid=92700055262507126&ds_rl=1244066&gclid=CjwKCAjwiJqWBhBdEiwAtESPaIzIFoDGvFz1LVMSzuvfwublWCskYfwt8kKMrQRmW0fyM5kLxo9tNBoCH5IQAvD_BwE&gclsrc=aw.ds
You fit it to an outside tap and turn it on, the pressure will go up giving you the standing pressure, then open another tap inside and check the gauge again and this will give you the working pressure.
Hope this answers your question.
Hi,
Hope you are well ! Amazing video !!!
Just a quick one. If the draw off for a sink is 2 LU. Then should it not be 4 LU in total. Because a sink has a hot and a cold tap. So am assuming the cold TAP will have a flow-rate of 0.2l/s and the hot TAP will have a flow rate of 0.2 l/s. So the CW pipe coming into the house should be sized to supply cold water to the boiler or water heater for hot domestic water and cold water directly to the taps.
Therefore, 0.2l/s of cold water going directly to the taps and 0.2l/s going into the boiler and into the taps (I know these values are not diversified but just for explaining reasons I ignored it).
Or am I overthinking it haha
Thanks !
Hi, and thanks for your support. I am well and getting ready for my new students to start soon ;) Hope you are well too.
Thank you for the very good question. No you are not over thinking, you are thinking in the correct way. ;)
To answer your question, yes true, it would be 4LU, and yes it is 2LU on the cold and 2LU on the hot but we do not add them together as they are 2 different pipe runs and completely different. But if we are using a Combination boiler, I would have to add all the outlets of hot water together (bath 4LU, basin 1LU and sink 2LU) equaling 7LU and show the boiler on the drawing for the cold water. Yes, then all this would change the size of the incoming main and the pipework going to the boiler. I would then have to draw another plan for the hot pipe runs and size them too but this time from the boiler to the outlets.
Again thank you for your great question and I hope my answer help.
@@mglplumbingtraining4067
Hi, thanks for replying ! Crystal clear ! You’ve explained it well ! Hot and cold LU’s are added before going into the combination boiler. But hot water is sized separately when leaving the combi-boiler to serve outlets !
Thanks ! Amazing channel !! Keep up the hard work ! Hopefully it will pay off !!
Thanks again !! And best of luck with your new students ! Am sure they’ll learn a lot from you !! 👌👌👌
Can you have a video on pump selection and tank selection? And the assumptions that we have to make
Sizing hot water return pipe and pump
I will be make them soon, just got to finish the sciences first. 🙂
Hello, is there a limit for max diameter? For ex i want to use same pipe in whole house pex D25. Is there any cons an pros by doing this? Besides the price?
Hi Julijus Buivydas, this is a great question and even got me thinking. Hope this answers your question.
The max we normally work to for inside a domestic dwelling is 76mm in copper and 63mm PEX, for underground pipework to the dwelling the max is 63mm for MDPE but this is very rare, the biggest I have worked within a domestic dwelling was 35mm copper and 32mm PEX When it comes to multi-storey (Flats, apartment and hotels) or industrial this size of pipework is common and have been known to go bigger. I have worked with 110mm copper and steel in these types of installations.
Yes, you could use 25mm PEX for it all but it should not be left anywhere the sun can hit it, as it will degrade it over time. It would work but you will still need to reduce it's size to make the final connections to the outlets. 15mm to Kitchen sinks, toilet and basins and 22mm to baths are the standard sizes of pipework to them. The cost would be greater but you would have the best flow ever to all outlets as long as your incoming main is larger than the pipework inside and you have good pressure.
@@mglplumbingtraining4067 yes the main question was if i can make the pipe work to every single draw off points D25 (we are talking about pex pipes) because as i heard too big pipe will reduces pressure in the house, especially in the shower and sinks. Plus if there is too big pipe in the shover, we will have to wait for a very long to get hot water, esspecialy over 15/20m distances. Planning to put in recirculating pump, but still does thos pump line should be the same D25 or it can be smaller? Likr D16 or something like that.
P.s. main pipe is D32 PE. In the house is 6 sinks, 2 showers, 2 WC, a bath tub, washing machine, boiler, dishwasher. 4 persons 150m2 farest ends 14m flat distance (~20m of pipe work)
As long as the mains pipework coming in is bigger and has the pressure it will not effect the pressure you should get. When you go from small pipe to large then it will have an effect and reduce the pressure. But when you design the system correctly the pipework will go from large to smaller which will keep the pressures you require. PEX pipework is for inside use and not for under the ground, your mains coming in would more likely MDPE.
If your pipework is 15 to 20 away from the heat sources, you already have a dead leg in the system, meaning the water would take to long to get hot at the outlet and would be a waste of water. It should have never been designed that way. No plumber would have fitted it like that. A secondary circulation (Bronze pump) would solve the problem of the dead leg but it would need to be design and installed correctly for it to work.
Very informative but would like to know how to convert LU to flowrate as the chart on page 13 doesn't make sense. Also, the sizes using BS EN806 are much smaller than those using the IOP guide. Why such a difference.
Thank you for your support and question.
Well, 1 LU is equal to 0.1 Litres per second (l/s) or (0.1 x 60) 6 Litres per minute (l/m), so if the whole installation in this video is 10 LU that would equal 1 l/s or 60 l/m. This is the best way of converting them. As the chart on page 13 is very confusing but from what I have worked out is, you get a ruler and use column 1 first using the l/s you have worked. then when you reach the bold line you go down and you can get the LU you need. But if you use my conversion you do get the same answer as the chart. Just reverse it. Say you worked out the bathroom needs 36 l/m divide by 60 seconds to get 0.6l/s and that is equal too 6LU.
The Institute of Plumbing Plumbing Engineering Service Design Guide was written in 2002 and is based on the old British Standard of BS 6700. This is now been replaced by BS EN 806: 2006. Yes, we do still BS 6700 for design and if you do read it at the start it does say as my dwelling are on mains water pressure 15mm pipe will do. I have found this incorrect on a number of faulty systems I have had to fix and Combi's are just not working to the requirements of the customers with 15mm all around. For me I always found the BS 6700 very hard for people to learn how to use and once the BS EN 806 come out, it just made it so much easier to do. I have tested both ways and I found BS EN 806 to be more accurate and came out with the same type of answer every time. As BS 6700, it seem to be more of how you follow the line and read the results. Everyone comes out with answer, ever to big, to small but sometimes just right. It can be very frustrating.
Hope this answered your question and has helped. 😊
@@mglplumbingtraining4067 Thanks you for your response.
I am working on a large commercial building with a number of showers, WCs and wash hand basins having a total LU of 126 and giving a pipe size of 35 copper. The equivalent using the IOP gives a total LU of 203 giving a pipe size of 54 copper which is a huge difference. Also, using your assumption that 1 LU is equivalent to 0.1 l/s, the 126 LU would be equivalent to 12.6 l/s with is huge for a 35 dia pipe. The graph doesn't make sense as between 15 LU and 300 LU there is very little difference in flow rate if you use the top line.
Now I know you are talking commercial. Yes, the BS EN 806 will not work for it. This is for domestic, if you read page 14, it informs you of this. I would be using BS 6700 to work out the size of pipework, which is what IOP is based on. So, 54mm for the mains in, sounds about right.
As for the chart showing the Design flow rate (QD) in l/s for standard-installations in relation to the total flow rate (QT) in LU. It is just showing us how they get the LU using the requires of the domestic system design. As I didn't design this chart, your guess is as good as mine. In table 2, it tells you the requirements for all appliance's, as shown in this video.
Sounds like it's going to be a fun job. good luck and enjoy 😀
@@ivanrebello3834 because the larger your total flow rate, the more diversity that can be applied to the system
How do you get access to British standards ?
Here is the link to get one but I will warn you now they are not cheap to buy...
knowledge.bsigroup.com/products/specifications-for-installations-inside-buildings-conveying-water-for-human-consumption-pipe-sizing-simplified-method?version=standard
Hope this helps
hello how much combi boiler loading unit ? my cold water in combi boiler and out for hot water. i dont know how pipe size. Please help thanx
6.3 KW boiler
You work it out the same way you would for the cold water, what appliances are using the hot water? So if you had 1 basin, 1 kitchen sink and a bath. you would add up their loading units and that would be your combi's units. Bath is 4, plus 2 for sink and 1 for basin equals 7 loading units. You then add your combi to the cold water drawing where it should be and size from there.
I am getting asked this one a lot so I am working on a video for both when you have combi's or an unvented cylinder on your cold water system. Plus adding the hot water sizing too.
Hope this has helped and answered your question. Any other questions please feel free to ask.
Boiler size does not matter as much, the important bit is how many appliances it is suppling as that will be the total loading units you would use.
@@mglplumbingtraining4067 Hello, thank you for your answer. Cold water is taken out of the tank and distributed to the equipment, and finally enters the boiler. It is distributed to the equipment as hot water. I can calculate of hot water coming out of the boiler, I can calculate of cold water coming out of the tank. But I don't know the cold water calculate that enters the boiler. in short, cold water is distributed from the tank and finally enters the boiler. I calculate from the combi to the tank. By giving the combi approximately 4 loading units. Is that true?
@@mglplumbingtraining4067 And how much loading units for per radiator?
Now why did youtube recommend this to me?
Your guess is as good as mine? 😆