Browse Forums General Discussion 1 Sep 13, 2022 10:56 pm Hi all, We are planning a small totally offgrid house in Yarra Valley (Vic) and after some advice on best practice to install a rainwater collection system. Have attached a house plan showing proposed location of downpipes and tank(s) We have not started or ordered anything yet, so welcome suggestions so we do it right. Current idea is to have a 15K house tank, 30K shed tank and 30K storage tank higher up the hill. The Shed tank will work in the same way as the House tank, just with bigger storage capacity. The 15K house tank is filled from house and verandah roof rainwater. The normal "top" level for the house tank will be 13Kl (15Kl max - 2Kl) When rainfall raises the level to near 15Kl (top of tank capacity), a submersible pump suspended near the top of the tank pumps the top 2Kl to the 30Kl storage tank higher up the property. As water is used in the house, a float valve in the house tank opens to supply water via gravity from the hill tank to keep it at the 13Kl level. House and Shed tank dual meshed air gap overflows would only be used if their submersible pump fails. Hill tank overflows into a garden area We want to use a wet charged downpipe system for the verandah downpipes, but not sure how to connect everything up and pipe sizes to use. Plan shows 100upvc for underground wet pipes, but not sure if this is best practice. We like the idea of the low tank inlet and floating (waterboy) pump outlet to maximise water quality. Is 50mm ok for the low inlet and does it need a valve? if so what type - a manual tap or something one-way or automatic? Planning on installing a DIY sediment trap just before the tank as per forums. Am thinking we would need a SupaDiverta and first flush on each downpipe? If using a SupaDiverta, how much water goes down the stormwater pipe with the debris? What is the best way to connect the 2 high house downpipes near the tank? Would we benefit from having a small settling tank, and if so, how would this be incorporated? Also plan on having 2 cistern valves, gravity fed as main inlet and pump inlet as a backup. Drawings show a high house tank, but with leaf diverters on downpipes, I think we will need to go with a squat house tank as follows: Measurements: House roof=96sqmt Verandah Roof=54sqmt House Tank (squat type): 15Kl 1570mm H x 3500mm W Ground level=184mt Height gap between house tank_top and verandah gutter_base=1080mm Hill Tank: 30Kl 3150mm H Ground level=187mt Shed Tank: 30Kl 3150mm H Ground level=185mt Melbourne 1:20 ARI 5 minute average rain intensity is 2 - 2.3 mm/min Thanks in advance for any help. Cheers, SustainableHouse Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Rainwater Harvesting and Wet charged System Design 2Sep 14, 2022 11:04 am You have good Best Practice knowledge and have posted good information. I hope to find time either tonight or tomorrow night to post advice. You mention being off grid but also mention having a storm water system. Where will this drain to? 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: Rainwater Harvesting and Wet charged System Design 3Sep 14, 2022 11:14 am No actual stormwater system but was just referring to the straight down path the debris/water takes after being deflected in the SupaDiverta which would probably be deflected down the slope towards the driveway drain which then disperses into the bushland. Cheers. Re: Rainwater Harvesting and Wet charged System Design 4Sep 15, 2022 9:50 am I'll start off by giving each downpipe an identifying number. DP1. House lower right. DP2. House top right. DP3. Veranda top right. DP4. Veranda lower right. DP5 Veranda lower left. DP6. House lower left. DP7. House top left. Where will DPs 1 & 2 discharge? 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: Rainwater Harvesting and Wet charged System Design 5Sep 15, 2022 10:10 am DP1 & DP2 - currently the drawings have them as downpipe spreaders discharging onto the verandah roof directly below them. Re: Rainwater Harvesting and Wet charged System Design 6Sep 15, 2022 10:30 am Does the porch have a roof? How does it drain? 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: Rainwater Harvesting and Wet charged System Design 7Sep 15, 2022 11:01 am The porch is open angled slats to provide sun/shade to windows for passive solar heating/cooling of concrete slab inside the house. So no roof or drainage. The porch slats adjacent to the verandah will provide shade to verandah slab in summer. Re: Rainwater Harvesting and Wet charged System Design 8Sep 15, 2022 1:58 pm SustainableHouse Current idea is to have a 15K house tank, 30K shed tank and 30K storage tank higher up the hill. The normal "top" level for the house tank will be 13Kl (15Kl max - 2Kl) There are a few things to discuss but I won't do them all at once so it is easier to follow. The first thing I noticed was the 15k house tank which is D 2.5 m, H 2.47 m. This actually calculates to be 12,125 L. A lot of tank manufacturers are now putting the overflow provision into a domed roof because people like myself started letting people know that the claimed storage capacity of their tank(s) was less than claimed once an overflow pipe was installed at the top of the side wall. If your tank has a flat roof and will also have an overflow pipe fitted at the top of the wall, then its storage capacity will be even less than 12,125 L. Having a very high overflow outlet on most tanks compromises the overflow pipe's discharge capacity because it reduces the height of the water above the overflow outlet's invert. The tank's mitigation capacity will also be compromised. It is a sad indictment on the industry that tank manufacturers are not required to state their tank' overflow capacities. The house and veranda will have about a 200 sq m roof area and so during a bare minimum qualifying 1:20 year rain event, the roof will produce about 435 lpm. The overflow mesh restricts the tank's overflow discharge rate and so you are wise to have already decide to install the twin mesh Air Gap made by Rainharvesting but a single tank even when fitted with an unmeshed 100mm horizontal overflow outlet able to have 175mm of water above the invert would only flow at 443 lpm (Source: AS/NZS 3500.1 Storage Tanks) which would be an insufficient safety margin in any case. The 15k tank will also be too high to drain the 3 veranda downpipes which also service 2 higher house downpipes. Have you considered having three 5,000 L tanks en-masse? They are made in large numbers and so three would be about the same cost as a 15,000 L tank. The added advantages would be their use as settling tanks, their lower height plus additional overflow capacity. You can also chase a poly tank in ground on a compacted sand base rather than site them on a slab. The ones in the photo are chased in about 80mm. You don't see vertical risers or overflow pipes because they use a Supadiverta system. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ If the bottom of the gutter is 2.4 m to the ground, then the tank's top inlet would need to be no more than 2.1 m above ground but fitting leaf diverters will need factoring. The best current leaf diverter is the ICON Leaf and Debris Controller but it is a larger unit than the others sold and will lose +100mm more head than the others...but they are well worth it. Leaf diverters have several advantages but one overlooked one is that if you have a tank with an overflow outlet high up on the tank's wall and not the roof, the vertical riser can divert water directly into the tank at the same level as the overflow outlet. This usually gains about 200mm head. Because the water is already filtered, you can also fit a 40/50mm low restriction inlet 100-150 mm above the bottom of the tank and this will supplement the inflow pipe's flow capacity along with other advantages. More later. You can buy the ICON unit by ordering at the Bunnings Special Orders desk (Bunnings sell other ICON products). Bunnings use to sell them for $38. I think that TradeLink and Reece also sell them but check their price. If you buy one, you will be able to calculate the tank's most suitable height without guessing. Re the Supadiverta, you will lose about 500-550 mm of head which includes the upper section of downpipe between the gutter and the Supadiverta's top inlet if there is an eave and the Supadiverta is fitted to the wall, Some of this loss will be reclaimed by not needing a vertical riser and eliminating buying a leaf diverter. Compared to the ICON unit, it would lose about an additional 50-60mm head if the two units were connected to the downpipe at the same location. The Supadiverta was designed more to facilitate rainwater harvesting best practice and increase yield in the urban situation but I generally advise people who are off the water grid not to use it because the annualised yield loss due to the internal 750 micron filter is about 3.5% to 4% (which is world's best for a diverter with an internal filter). Rural properties off the water grid invariably need to harvest every drop but many of our researched improvements can be incorporated into standard wet system designs which is what we are doing here. Plenty more coming after you digest this opening lot. 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: Rainwater Harvesting and Wet charged System Design 9Sep 15, 2022 8:58 pm Lots of good ideas and suggestions to work through. If we use a squat 15K house tank 3500W x 1570H the gap between tank top and gutter base is 1080 which should be plenty. House Slab (FL) FFL = 184.20mt Water tank slab FFL = 183.95mt (250mm lower than house slab) Water tank height = 1570 Water tank top above (FL) = 1570-250=1320 Gutter base above (FL) = 2400 Gap between tank_top and gutter_base = 2400-1320 = 1080 We used the ICON diverters at a previous house for vege garden water so agree they work very well. The overflow margin is small and we could install 2 overflows, but as we are pumping the top 2-3K up to the Hill tank, the overflow would only be used if the pump fails anyway. Being in a bushfire zone and drinking the water, we want to use stainless steel for all tanks. We probably prefer a single 15K house tank to keep it simple with less plumbing, pumps and cost. For stainless, 3x5K is almost double the cost of 1x15K. Having screened leaf diverters, sediment trap and floating waterboy pump outlet should provide pretty clean water. A low outlet with slotted hose sitting on the tank floor will also help. Re: Rainwater Harvesting and Wet charged System Design 10Sep 16, 2022 10:24 am SustainableHouse If we use a squat 15K house tank 3500W x 1570H the gap between tank top and gutter base is 1080 which should be plenty. Water tank height = 1570 The overflow margin is small and we could install 2 overflows, but as we are pumping the top 2-3K up to the Hill tank, the overflow would only be used if the pump fails anyway. When rainfall raises the level to near 15Kl (top of tank capacity), a submersible pump suspended near the top of the tank pumps the top 2Kl to the 30Kl storage tank higher up the property. Plenty of head to play around with but keep in mind for future consideration that increasing a tank's height but retaining the same storage volume decrease the % of bottom inactive storage. I noticed that I previously posted the overflow pipe calculations for your roof and veranda area as based on the combined roof areas being 200 sq m whereas it is 150 sq m. The revised yield during a minimum qualifying 1:20 ARI is therefore about 320 lpm, not 435 lpm. (Gutter surface area must be addded). It is best practice to pump decanted water to a higher storage tank rather than have a suspended submersible pump draw unstratified water from near the top when it is raining. You will also need a check valve. Another thing to consider is the pump's required actual flow rate after deducting pipe friction and elevation losses given that you plan to only have 2,000 L mitigation. If you want to deliver let's say 260 lpm, you will need a big expensive pump. If you will have a fire pump, could you use it instead? Have you considered having more mitigation and a smaller pump?. The other thing to consider is the suspended pump's required critical submergence, you don't want the pump to draw a free surface vortex. The pump's mesh screen should prevent that but it will be a big pump. Best to ask before you buy. Pumping water to an inlet a few hundred mm above the bottom of the higher storage tank is more efficient than pumping up a vertical riser to the top of the tank. https://www.youtube.com/watch?v=HlvHczb ... ex=21&t=9s Floating Intake Filter Our launch has been delayed but if buying commercially or making your own, have one with a collar that prevents the 'filter' cage from settling on the bottom when the water level is low. You also need to be aware that many sold use 1,200 and 1,400 micron holes in the (expensive) stainless steel filter which is useless when water has already passed through 955 micron tank filter mesh. Also make sure that the hose and buoy are potable water quality. WET SYSTEM PIPES are an area of nearly 100% failure caused by old, poor or non existent regulations and the lack of a basic understanding of fluid dynamics by industry professionals and regulators. I'll explain the issues and suggestions for your pipes in my next post, just really short of time today. 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: Rainwater Harvesting and Wet charged System Design 11Sep 16, 2022 4:12 pm More good info from the last post to absorb and get me thinking. I agree the squat tank increases inactive storage but the head is needed. re: It is best practice to pump decanted water to a higher storage tank rather than have a suspended submersible pump draw unstratified water from near the top when it is raining. mmm, this one got me thinking. I had not factored the float on the pump will only rise and trigger during a rain event. Current plan is to use the Davey D25A submersible pump (12mt max head) and the 300mm float travel will uplift about 3000lt to the hill tank. When the pump stops, our pre-rain level will be about 11KL. Am now thinking how we can delay after rain for sediment to settle, then pump even a small amount above this 11KL level uphill and not having to wait until the float reaches its maximum of 14KL (during a rain event). re: best practice to pump "decanted" water to a higher storage tank How could we do this? I calc 6mt head max if pumping to top of hill tank from bottom of house tank and Davey D25A flows 120lpm at 6mt head. The 30KL Hill tank has 10KL for CFA so we could have the inlet at this level with a check valve. However the D25A has no issues at 6mt head (top of hill tank) so no check valve needed (1 less part to cause issues) and any drop would aerate the tank water as well, for what that is worth? Rather than a collar on the floating intake, I was thinking of having a lightweight tether on top of the float that sets how far it can drop into the tank. Re: Rainwater Harvesting and Wet charged System Design 12Sep 18, 2022 5:54 pm SustainableHouse I agree the squat tank increases inactive storage but the head is needed. You can calculate the required head + a safety margin once I have commented on the pipe sizes. SustainableHouse Am now thinking how we can delay after rain for sediment to settle, then pump even a small amount above this 11KL level uphill and not having to wait until the float reaches its maximum of 14KL (during a rain event). re: best practice to pump "decanted" water to a higher storage tank How could we do this? Just fit a floating intake filter and manually transfer water when needed and/or before rain. UNDERSTANDING WET SYSTEM PIPE ISSUES AND CAUSES The biggest problems with wet systems are the build up of sludge and the accompanying anaerobic bacterial activity which adversely affects the quality of the water retained in the pipes between rain events. A combination of poorly defined archaic and conflicting regulations are the catalyst for bad practices that are the norm for nearly all wet system installations. Eaves gutter roof drainage regulations are based on a 1:20 year storm event whereas a stormwater pipe’s regulations are based on a 1:100 year storm event, a rain intensity that is about 50% greater than a 1:20 year event. The different regulations are necessary due to stormwater pipes being required to also service surface drainage and water from silt pits supplied by ag pipes etc. Stormwater pipes are sloped and stormwater drains along the curved bottom. The minimum required sediment flushing velocity is recognised as 0.7 metres per second which is easily exceeded during light to moderate rain or further downstream where other downpipes also connect to the stormwater pipe. A wet (charged) system however is flooded and consequently flows with much less velocity than water with the same flow rate will flow along a pipe’s curved bottom. Non turbulent water in a flooded pipe flows fastest through the core and is mostly stationary on the walls due to friction losses. Low velocity is what causes suspended sediments to settle and build up as bed load. Even during heavy rain, the downpipe at the head of a wet system’s annexed stormwater pipe (which may also slope uphill to the tank) will rarely generate the flow velocity needed to flush sediment through the horizontal pipe, resulting in a continual long term build up of sludge along this section of pipe. EXAMPLE: A 100mm pvc DWV pipe has an internal diameter of 104mm which gives a volume of 8.5 litres per metre. This equates to an upstream flow rate from one downpipe of 51 litres per minute @ a velocity of just 0.1 metre per second (8.5 L x 60 = 510 lpm). Low velocities through oversized flooded horizontal pipes is why wet systems accumulate sludge. YOUR WET SYSTEM DPs 2 & 3 will drain 24 sq m and 18.4 sq m of roof respectively, a total of 42.4 sq m. Using 2.2 mm/min average rainfall intensity over a 5 minute duration as the minimum qualifying intensity for a 1:20 Average Recurrence Interval (ARI), we arrive at 93.28 lpm draining via DP3 to the head of the wet system pipe. If we refer to my previous example of a flooded 100mm DWV pipe flowing at 51 lpm having a velocity of just 0.1 metres per second, you can understand that sludge will continually build up in the approximately 9.6 metre length of pipe between DPs 3 & 4. The sludge build up will be lessened by fitting leaf diverters but you may be surprised as to how much finer detritus still manages to wash through mosquito proof mesh. Just think of the mosquito proof mesh on a water tank’s top inlet and how much sludge still manages to build up in water tanks! Flushing is achieved in a flooded pipe by turbulence generated by either velocity or directional changes. You won’t have any turbulence until DP 4 but that will be short lived because the velocity will still be inadequate to generate turbulence due to DP 4 only draining about 18.4 sq m (38 lpm) during a 1:20 ARI plus 24 sq m draining from DP1 to DP 4 roof area, an additional total of 42.4 sq m or 93 lpm during a 1:20 ARI. 93L + 93L = 186 lpm which sounds a lot but the velocity through the 100mm (104mm ID) DWV pipe will still only be 0.365 metres per second...and what about the rest of the time when you have normal rainfall? I won’t go deep into the conflicting archaic plumbing regulations as the post would end up a tome but it can be strongly argued that standard systems do not meet the NCC Part 3 Performance Requirements that state: “Performance Requirements BP6.1 Stored rainwater (1)A rainwater harvesting system must be designed, constructed and installed in such a manner as to reduce the likelihood of stored rainwater becoming contaminated or otherwise posing a hazard to public health. BP6.2 Rainwater harvesting system installation (1)A rainwater harvesting system must be designed, constructed and installed in such a manner as to— (a)avoid the likelihood of contamination of water within the rainwater harvesting system, the water service, or the Network Utility Operator’s drinking water supply (if connected)” The National Construction Code is a performance based document and Performance Solutions can be used provided they meet the Performance Requirements within the NCC. Note that you need a leaf diverter fitted to the downpipe to be able to 'safely' reduce the wet system pipe size. You don't want a dead bird or something to get stuck. Let see how a 50mm (51.6mm ID) DWV pipe would perform draining the head (DP3 to DP4) of your wet system. I have used the friction loss calculator linked below. I have found the following to be the simplest way to explain head loss/requirement. https://www.engineeringtoolbox.com/hazen-williams-water-d_797.html PVC pipe roughness coefficient is 150 and I have entered 100 metres of pipe so I can divide by 100 to get a head loss per metre at the entered flow rate of 2 L/sec (120 lpm) which gives us a modest safety margin over the 93 L minimum qualifying figure for a 1:20 ARI. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ The head loss is 18.83 mm/metre, let’s say 19mm. With an added friction loss allowance as equivalent pipe length for the elbow, we will calculate the pipe run between DP3 and just before DP4 as being 12 metres. 12 metres x 19 mm = 220mm. You plan to have much more potential head than this. Apart from the huge advantage of the system regularly flushing, the 50mm pipe also retains less than ¼ the volume of the 100mm DWV pipe when it stops raining! Flow rates and friction loss calculations along a wet system pipe that is served by more than one downpipe is frequently misunderstood because each successive downpipe also restores friction losses, the same way that a water tower restores pressure losses in a main pipeline. To fully utilise this recharge, it is highly preferable for 45 degree junctions to be used instead of 88 degree junctions (tees) as connections. Will DP 1 service DP4 or DP 5...or both equally? The answer will affect the successive pipe sizes but a 65mm DWV pipe will be needed at DP4 regardless. The 65mm DWV pipe has an ID of 63.6mm and the 80mm DWV pipe has an ID of 76.2mm. DP6 will recharge the wet system which will be very good due to the longish run from DP5 and the closeness of DP6 to the tank. A sediment trap could be fitted near the tank. A low restriction inlet need not be large unless it needs to supplement a vertical riser’s discharge rate but a 40mm one has a good flow capacity even with small.head pressures. The low inlet's other advantage when used with a vertical riser is to equalise the downpipes and the vertical riser’s water level with the tank’s water level. This is also another reason why I would be keener to manually pump water to the storage tank and keep the water level maybe 1/3rd full rather than nearly full. I assume DP7 will be a dry 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. Re: Rainwater Harvesting and Wet charged System Design 13Sep 19, 2022 4:52 pm As always, SaveH2O has provided a wealth of great information to digest, thank you. re: Just fit a floating intake filter and manually transfer water when needed and/or before rain. A simple manual solution is often the best, perfect! Using the smaller 50mm DWV for DP3 to DP3 makes perfect sense. DP1: current drawings show it feeding equally to DP4 and DP5 via a spreader. Alternatively, we could pipe DP1 over the verandah roof to a spreader at DP5, or even avoid the gutter and bring it to LHS of the gutter end and plumb it directly into the DP5 downpipe just above the Leaf diverter. We have options, so which DP1 exit will give us the best outcome for wet pipe sizes after DP4? DP6: would have a Leaf diverter at the same height as the verandah to make it easily accessible to clean. As you mention, DP6 would recharge the wet system but only 3-4mt from the tank, so having a concrete slab might make placement of a sediment trap tight if the tank inlet was on the RHS. One option is to continue the wet pipe along the same straight path towards the bottom LHS of the slab to an inline sediment trap, then connect to the tank on the LHS via a 45Deg horizontal bend. DP7 could run down and across to connect into DP6 so all DP are wet system and provide extra charge. I think this is a better option than having DP7 as dry? Would it be better for DP7 to have its own leaf diverter or just connect to DP6 before the DP6 leaf diverter? What DP sizes would be required dor DP6 & DP7 FFD: below every leaf diverter to get the best quality water at the tank inlet. DP3,4,5 FFD's could have 1 combined drain downhill near DP3. DP6,7 FFD's could drain downdhill near DP7. Tank low restriction inlets: For corrugated stainless tanks, I can only find references to 25mm and 50mm. Would 25mm be ok? If all DP's feed the wet/charged system, is there any benefit to having a riser at the tank as well? What valve type is recommended for the low inlet on the house tank fed by the wet system? What valve type is recommended for the low inlet on the hill tank fed by the house tank pump? Re: Rainwater Harvesting and Wet charged System Design 14Sep 20, 2022 9:40 pm SustainableHouse DP1: current drawings show it feeding equally to DP4 and DP5 via a spreader. This is good. A 65mm (63.6mm ID) DWV pipe holds 3.18 L/m which equates to a flow rate of 190.8 lpm @ a velocity of 1 metre per second. We will use the 1:20 ARI minimum as our control. DP4 pipe will already receive 93 lpm from DP3 during a minimal 1:20 ARI plus the drainage from an additional 30.4 sq m (18.4 sq m + 12 sq m) or 66.9 lpm = a total of 159.9 lpm. This equates to a velocity of 0.84 metres per second through a 65mm DWV pipe. Melbourne region has a long term average of 5 days of heavy rain per annum but there has been an increased frequency in recent times due to there now being more fast moving, short duration storm cells. Anyway, you plan to have plenty of reserve head plus the pipe will have plenty of reserve flow capacity (I like to keep to a max velocity of about 1.3 – 1.4 mps) but most importantly, the wet system pipes will be regularly flushed during heavier rain with less intensity than a 1:20 ARI. DP5 pipe will receive 159.9 lpm from DP4 plus water from an additional 29..2 sq m (64.2 lpm), a total of 224.1 lpm during a minimum 1:20 ARI. This is a velocity of 1.17 mps through a 65mm DWV pipe which gives little safety reserve at desirable maximum velocities and so an 80mm (76.2mm ID) DWV pipe should be fitted just before DP5. The 80mm DWV pipe has a volume of 4.56 L per metre which gives a flow rate of 273.6 lpm at a velocity of 1 mps and our control 224.1 lpm = a velocity of 0.82 lpm. This pipe will provide regular flushing with an adequate lesser velocity during 'lesser' heavy rain events. Accepting additional flow from DPs 6 & 7 will require plumbing a 100mm DWV pipe just before DP6. You can easily calculate the lesser volume of water retained in the system between rain events once you know the pipe lengths and compare it to the volume that would otherwise have been retained by a 100mm (104mm ID) DWV pipe system that holds 8.5 L/metre. The far greater advantage however is having substantially cleaner wet system pipes that won't degrade retained water as would a standard but substandard wet system. SustainableHouse .....having a concrete slab might make placement of a sediment trap tight if the tank inlet was on the RHS. Agree. One of your opening post diagrams shows an oversized rectangular tank slab. Is there a reason for this? My main tank sits on a chased circular slab which replaced a rectangular sand box. The sediment trap diagram below shows a pipe reducer but we use a reducing invert taper now. The outlet/flush pipe is size reduced to increase flushing velocity and save water. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ SustainableHouse One option is to continue the wet pipe along the same straight path towards the bottom LHS of the slab to an inline sediment trap, then connect to the tank on the LHS via a 45Deg horizontal bend. Sounds good but I would never hard fit a non flexible pipe to a tank. A sediment trap should be fitted about 4 metres past the last area of turbulence. You can always plumb two, the first one being between DPs 5 & 6. SustainableHouse DP7 could run down and across to connect into DP6 so all DP are wet system and provide extra charge. I think this is a better option than having DP7 as dry? Aesthetics may decide the best way. Although not directly related to a wet system, the video below demonstrates how the height of water regardless of its volume is what exerts pressure. Wet systems however are further complicated by having increased flow rates at each DP junction and DPs servicing different roof areas at different intervals along the flow path. https://www.youtube.com/watch?v=933XNdC ... =81&t=342s SustainableHouse Would it be better for DP7 to have its own leaf diverter or just connect to DP6 before the DP6 leaf diverter? The ICON diverter is designed to also accept two pipes. Bunnings use to sell them for $38. Your decision on FFDs may affect your final design choice. SustainableHouse What DP sizes would be required dor DP6 & DP7 I have assumed all DPs would be 90mm round. SustainableHouse FFD: below every leaf diverter to get the best quality water at the tank inlet. DP3,4,5 FFD's could have 1 combined drain downhill near DP3. DP6,7 FFD's could drain downdhill near DP7. It would be best if you had a manual draining system as dripper FFDs have high yield losses. Manual systems also allow you to collect and use the water. I have been thinking of selling a simple 100 mm first flush kit for use with standard rainwater harvesting systems (non Supadiverta). It would use the Supadiverta's optional 100mm first flush bottom bracketed cap but that would mean that I would be left with odd top caps as the injection mold cannot be adjusted to mold just one cap. A H1 member who posted on another thread used the system, it is uncomplicated, uses far fewer fittings and would be substantially cheaper than other commercial 100mm first flush diverters if I did commercialise it. The bracketed cap slopes towards a 19mm outlet which means that a leaf diverter must be used at the DPs to remove larger objects. I can send some of the bottom bracketed caps to you free of charge if you are interested. You would need to fit a junction at the top of the flush pipe so that water overflowed down it to the wet system pipe once the flush pipe filled. A 100mm x 90mm pipe reducer allows use with an upper 90mm pvc pipe. A 100mm (104mm ID) DWV pipe has nearly 50% more volume than a pvc 90mm (86.2mm ID) stormwater pipe which is important when collecting the initial dirty roof wash. https://www.bunnings.com.au/holman-100- ... r_p4770344 Note that the Bunnings price is obscenely high. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ You can also connect the bottom outlet/drain pipes from all FFDs to a common subsurface pipe and connect it to a sealed tank fitted with an outlet valve and a meshed vent pipe that is a tad higher than the top of the FFDs. It wouldn't be exactly like the one in the photo below because that feed line also discharges to the storage tank which is unlike my description. The vent pipe will also exert pressure on the holding tank and it is best not to have it extend too high above the tank. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ SustainableHouse Tank low restriction inlets: For corrugated stainless tanks, I can only find references to 25mm and 50mm. Would 25mm be ok? Yes because you won’t need to supplement the wet system’s flow rate if you have a vertical riser. Just keep in mind that a low restriction inlet will always have priority flow because it operates with more head than a vertical riser does.. SustainableHouse If all DP's feed the wet/charged system, is there any benefit to having a riser at the tank as well? To eliminate the vertical riser, you would need a large bottom inlet. The flow rate off the 150 sq m roof during a minimum qualifying 1:20 ARI would be 330 lpm and so I would design for +400 lpm. This would require a 100mm inlet. A vertical riser fitted with a flap valve would be much cheaper. Fitting a 50mm low restriction inlet will slow the vertical riser's discharge velocity. Also a quick mention here that oxygen rich low density water entering a tank through a low restriction inlet quickly dissipates energy and flows upwards due to it entering a region of higher density water. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Vertical risers dropping water from a height into a tank cause issues with sediment re-suspension and bubbles being sucked into pumps when water levels are low but you intend to maintain a good water level which will nullify these issues unless the submersible pump is suspended near the water surface.. I have assumed that you will be using the storage tank to supply head pressure to the house but after just having another look at the contours, I am feeling that I might be wrong. Am I? SustainableHouse What valve type is recommended for the low inlet on the house tank fed by the wet system? Ball valve. It is always best to be able to isolate the tank. SustainableHouse What valve type is recommended for the low inlet on the hill tank fed by the house tank pump? Ball valve. You will also need a check valve, check to see if the pump you choose has one. 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: Rainwater Harvesting and Wet charged System Design 15Apr 26, 2023 8:25 pm If I have a 150mm subsurface pipe going to my tank at around 858lpm is there any flexible potable water pipe I can buy to connect into the tank via a low restriction inlet? I can't seem to find anything but I love the idea of it! Once you know the basics, the rest is easy. Read my post in the thread linked below. viewtopic.php?p=1919271#p1919271 2 19548 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 8444 DIY, Home Maintenance & Repair But if it is a ground level open pit, then it is not a charged system. No surprises there. The pipes have obviously been altered and there would be a reason for this.… 3 31321 |