Browse Forums General Discussion Re: DIY sediment trap on charged rainwater harvesting system 2Nov 06, 2021 11:55 pm 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: DIY sediment trap on charged rainwater harvesting system 4Nov 13, 2021 1:11 pm 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: DIY sediment trap on charged rainwater harvesting system 6Nov 14, 2021 2:21 pm 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: DIY sediment trap on charged rainwater harvesting system 8Nov 15, 2021 9:39 pm 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: DIY sediment trap on charged rainwater harvesting system 10Nov 19, 2021 7:34 pm stacey33 Your response has really helped my understanding. I always keep in mind that other interested homeowners also read these threads and I try to promote a wider understanding rather than simply instruct so they too are able to help others. Docendo discimus. stacey33 With the information you provided above is that provided on the assumpton I also use a vertical riser from the bottom feed inlet to meshed inlet on top of tank? I'll be relying on a 50mm inlet unfortunately, as I don't want to have to cut out a new section in the tank to make it a 65mm or 100mm. Combining the 100mm DWV pipe with a shortish 50mm flexible hose will allow you to eliminate the vertical riser. Read on to find out why. The 50mm low restriction inlet uses less pipe and elbows (less friction loss) plus gains head over a same size vertical riser by virtue of the water level in the tank always being lower that the level of the water discharging at a height above the riser’s top elbow's invert. You have an unusual situation that I haven't come across before in that you have a single high yield (but currently undersized) downpipe and a supply of 100mm (104mm ID) DWV pipe. Normally it would be unwise to plumb the 100mm pipe because of the lack of sediment flushing velocity even during a high intensity rain event. The saving grace of course is the sediment trap. The smaller 80mm and 65mm DWV pipes and fittings are also usually more expensive than the much more commonly used 100mm pipe and so it's a good result. Calculating required head when having a single downpipe even when there are two different pipe sizes is quite easy. We are able to get a good idea of friction losses generated by various hydraulic heads through different lengths and sizes of pipe by using the simple friction loss calculator below. https://www.nationalpump.com.au/calculators/friction-loss-calculator/ Let's design your system to cope with a 250 lpm inflow rate using a 13.5 m length of 100mm DWV pipe joining a 1.5 m long 50mm flexible and UV stabilised hose that connects to a 50mm low restriction inlet. By entering a 250 lpm design capacity flow rate and the 104mm diameter of the 100mm DWV pipe, we find that the pipe loses 0,24 m of head over a 100 m distance. In other words, this is the required head to generate this flow rate. There are variables such as a wet system's usual sediment build-up but this will not be applicable to your system. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ The two 100mm 90 degree elbows are each deemed to have an equivalent friction loss pipe length of 3.7 m. If you use a 13.5 m length of 100mm DWV pipe with two elbows, the total equivalent length of 100mm DWV pipe is 20.9 m. The friction loss is therefore 240 (mm) x 0.209 = 50.16 mm. Let’s say 50mm. To remove any doubt, we can also run the figures through a flow calculator BUT it must be one that is used for gravity pipe flow. A Hazen-Williams flow calculator satisfies this requirement. https://www.omnicalculator.com/physics/pipe-flow Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ 4.17 x 60 = 250.2 lpm. Now for the 1.5 m of 50mm flexible hose. This can be complicated because of the turbulence at the 100mm x 50mm reducing taper between the 100mm pipe and the 50mm hose but we won’t worry too much for now. You will see why later plus the flexible hose will I assume more likely be one meter or so in length.. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Friction loss is 84.8 mm per metre or 127.2mm for 1.5 m due to pipe friction losses increasing exponentially with increased velocity but we have to add the 50mm head loss for the 100mm pipe, bringing the total head loss to let’s say 180mm. We do however also have to factor the turbulence sapping friction loss at the taper but if you have measured the head from the bottom of the leaf diverter and not at the bottom of the mesh to arrive at 220mm head, the available head would be +300mm. I have to stress here that these simple calculations are for a single downpipe, not downpipes in unison that also serve as water tower pressure recharge stations along a carrier pipe. Pipes have friction losses all along their length even though the water flows along the pipe at the same velocity. This video demonstrates this. https://www.youtube.com/watch?v=_hSL9_eo4n8 stacey33 I was not provided any information about the tan koverflow capacity, however, I will check with the manufacturer. Tell me their response because they won't know. This is vital information and it is staggering that manufacturers don't provide the information or even (seemingly) realises it's importance and don't bother asking a plumber. Just crazy. stacey33 I plan to purchase one of those Rainharvesting air gap adapters to help matters. A great product. Minimises maintenance and increases the outlet's flow capacity. Brilliant. stacey33 The overlow outlet is 90mm. They did do the claculation of tank szie based on roof area and recommended a 20,000 litre. This demonstrates a common sub standard practice. Knowing the roof area to be harvested should have them also calculate the roof drainage rates at varying rain intensities. Your area's bare minimum qualifying rain intensity for a 1:20 ARI is most likely 2.1666 mm per minute (130 mm/hr) average intensity over a 5 minute duration. This equates to a total roof plan yield of 303 lpm. A 90mm PVC-u stormwater pipe is measured as an outside diameter, the inside diameter is 86.2mm. The mesh invariably has an impervious coating around the wire mesh outer edge which reduces the flow path to about 84mm. Meshed '90mm' outlets flow at about 190 lpm wirh minimal mitigation (maybe 15 mm) above the outlet while the unmeshed ones flow at about 235 lpm. Your tank's overflow capacity is less than your bare minimum 1:20 ARI inflow capacity. I would design the tank’s overflow capacity to be about 370 lpm. You can easily achieve and exceed this by having a second overflow pipe connecting to a 45 degree junction fitted to the outside vertical overflow pipe but above the air gap. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ A familiar high mounted overflow pipe with minimal mitigation. Mitigation provides a storage and higher discharge safety buffer during heavy rain. A horizontal drain pipe is very inefficient when compared to a vertical drain pipe. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Once you know the basics, the rest is easy. Read my post in the thread linked below. viewtopic.php?p=1919271#p1919271 2 19521 There is a whole lot more to know than just the answers you seek but they are a good start. Overflow outlets have a mosquito proof mesh. These… 3 8434 If you have a floor waste, turn on your sink and put your ear down to the central floor waste and listen. If you can hear water running then they all connect there. If you… 10 12140 |