Browse Forums Eco Living Re: Need advice on our rainwater collection and storage syst 41Oct 31, 2012 12:42 pm Thanks for covering for me there SaveH20. I've been busy with the prepping the tank pad and the tanks arrived yesterday. Tanks are now in place with 4" of water in 2, 3 & 4 to weigh them down. Tank 1 is half full. I've only fitted valves to tank 1 at this stage so as to access water. I've made some minor corrections to the diagram in my last post. The tankvacs are now shown coming through the side wall of the tanks not the roof. I've also upgraded from the 3x 25mm outlets to 32mm. Balance lines are still 50mm. Link to larger image I've also drawn up SaveH20's sediment trap / first flush system for my plumber. I thought it would be of benefit to post on the forum for future reference. John Link to larger image Re: Need advice on our rainwater collection and storage syst 42Oct 31, 2012 2:39 pm I guess you said it there is more than one way to skin a cat. Bottom connecting tanks for balancing is fine but remember if all open one tank leaks all water lost. I have used it on many occasions but only leave the valve open to achieve equilibrium. Not uncommon for a tank to leak. 1 in 20 year event 235mm not sure how much makes it into the tank certainly not 100%. It would be good to know future use, what reference is used for 1:20 rain fall event. I hardly see the vertical risers into tank 2 ever been used. Yes you reduce costs on the waterboy and tankvac by making your own. Good luck Pulpo Re: Need advice on our rainwater collection and storage syst 43Oct 31, 2012 11:29 pm Pulpo It would be good to know future use, what reference is used for 1:20 rain fall event. Hi Pulpo, AS/NZS 3500.3:2003 Table E1 and figure E3, area 1. The hourly rainfall is based on a 5 minute intensity. For example, a Melbourne 1:20 ARI is given as 130 mm/hr or an average of 2.17 mm per minute for 5 minutes. In effect, it could experience a severe short lived storm that delivered over 11 mm in 5 minutes to qualify as a 1:20 ARI and yet it may have had less than 12-15 mm over one hour. The system shown in the diagram has been designed to allow the two Tankvacs to also replace four overflow pipes and factors hydraulic transfer rates, mitigation, the regions rainfall pattern and the Tankvac overflow frequency during the wet season as it is custom designed. Unfortunately the system and calculations will not relate to many other visitors systems that are either planned or need upgrading. I will give a summary of the most effective changes people can implement to improve their tank water quality once John's tanks are fully installed and tested. 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: Need advice on our rainwater collection and storage syst 44Nov 01, 2012 4:48 pm Hi John, For compliance, your house roof area requires three 100 mm downpipes (on each side) with gutters that have a cross sectional area of 8,000 sq mm. This is without factoring the multiplier to allow for the sloped roof area. Factoring the slope would make the required gutter cross sectional area about 9,500 sq mm. Good roof drainage design is dependent on proper downpipe positioning and this is something that is not regulated. You have posted that the company has agreed to fit three downpipes on both sides for compliance but for your house and situation, I now think that two well positioned downpipes on each side would actually be better even though the drainage would not be compliant! The reasons why are... Having three downpipes on each side would place those downpipes at the middle and two end posts. This would be good as the high points would be above the other two posts and the distance between would allow for a good slope and drainage. Readers should note that there are 5 posts on each side. The two downpipes as shown in the sketch (opening post) are badly positioned at both ends of the gutter as the greater roof area is between the downpipes and the high point would be 8 metres away from each one. Each downpipe is only drained to from one side by 8 metres of gutter. BUT... If the downpipes were positioned on the second and fourth posts, the downpipes would be drained to from both sides and the short four metre distance from the high points to the downpipes will allow for better slope and gutter flushing. Two 100 mm downpipes would be more than adequate to drain the roof in a 1:20 ARI if positioned as above. If they were positioned as originally drawn, I am absolutely positive that they would overflow (unless you had huge gutters) plus the gutters would carry a lot more weight. 1 litre of water = 1 kg. Compliance is a joke anyway as many rooves have poor drainage as a result of poor design (downpipe positioning) but the design will often still be compliant. Non compliant and poorly designed roof drainage is endemic on new houses in Australia. As written in an inquiry report to the NSW parliament last year, the Office of Fair Trading instructed inspectors to randomly inspect display homes for roof drainage compliance during the inquiry. Of the 35 display homes inspected, only one was found to be compliant. http://www.smh.com.au/nsw/hidden-report ... 1hx55.html So why would it be better to have two non compliant 100 mm downpipes positioned as suggested rather than having three downpipes? The reason is because you are harvesting the water through a wet system and instead of the end downpipe harvesting 25% of the roof area from 4 metres of gutter, the furthest downpipe would now harvest 50% of the roof area from 8 metres (4 m x 2) of gutter. This would substantially benefit the flushing of the top part of the wet system plus it will create greater turbulence that will keep detritus in suspension for longer. You will also save by only having 2 downpipes and leaf diverters plus 4 metres less 100 mm pipe. I would normally not suggest that someone fits non compliant roof drainage but in this instance if you follow my suggested design, you will have a short four metre slope to all downpipes, the 100 mm downpipes are more than adequate to cope with the volumes expected and the end downpipe supplying the wet system pipe will harvest 50% of the volume off the roof rather than between 25-33%. This will provide much better flushing and this is important for wet systems. NOTE: 90 mm (OD) round downpipes are rated at 4.2 lps. 100 mm (104 mm ID) round downpipes have over 40% more internal volume. 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: Need advice on our rainwater collection and storage syst 45Nov 01, 2012 7:42 pm Great post SaveH20! The advice just gets better and better. Makes complete sense to me. I think another drawing is on the cards so the plumber knows what I want. John Re: Need advice on our rainwater collection and storage syst 46Nov 01, 2012 11:35 pm Update: Tankvacs have now been deleted from the design. Camel tanks would not warranty if fitted as it would require cutting through the side wall of the tank. Link to full size image 100mm overflows will now be fitted to all 4 tanks and converged to a pair to waste. To balance inflow the 2x 50mm infeeds have been moved from tank 3 along to tank 4. Tank 4 would serve as a large first flush and wet-system-flush-collector every time it rains. Water for outside use will be drawn from tank 4. Vertical risers have been split into tanks 1 & 2 to further balance the system while the garage roof remains at tank 3. During rain the wet system pipes will purge retained water to tank 4 prior to discharging up the vertical risers. Therefore any water feeding in via the risers would be of good quality. The wet system can be drained if need be during long periods of no rain. The 2 x 50mm infeed valves would be closed temporarily while draining. The system has been simplified with the further benefit of reduced cost. John Re: Need advice on our rainwater collection and storage syst 47Nov 03, 2012 11:29 am There have been some PM's sent about experiences with PVC pipe leaking/cracking at the connections. The big mistake people make when connecting PVC pipe is not applying the glue correctly. The glue is actually not a glue, the pipes are solvent welded. The solvent must be applied with the correct amount as it melts the two pipes and when they are fitted together, they fuse together to become one. It is important that the process is allowed to take place as moving the pipes within the first 5 minutes or so can disrupt the process and the melding of the two surfaces may be compromised. One big mistake people make is applying the solvent to only one surface. The solvent MUST be applied to both surfaces. Another huge mistake is applying too much as this can leave a large concentrated amount sitting on one fitting when the two parts are pushed together and this solvent pool will eat into the pipe or fitting and considerably weaken it. Another big mistake is to not use priming fluid or to apply it incorrectly. The priming fluid not only cleans the two surfaces, it most importantly removes the surface coating or glaze and this allows the solvent to work better. The priming fluid must also be rubbed on with a cloth as this cleans the surface whereas putting it on with a brush does not and this is why containers of priming fluid are not supplied with a brush. 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: Need advice on our rainwater collection and storage syst 48Nov 04, 2012 8:33 am Update: Tankvacs have now been deleted from the design. Camel tanks would not warranty if fitted as it would require cutting through the side wall of the tank. Hmm good reason to avoid Camel tanks. Anyway cannot see how the overflow works on camel tanks as they show no diagrams. When I order poly tanks they ask where you would like the over flow and out let being placed. In fact in helping one being delivery the overflow was installed on site, hole saw made in tank. Anyway you can make your own tank vac. The new setup I think is slightly better. I concur regarding the solvent, I've had plumbers who do not use the primer, hmm I would not want to use it everyday either. It makes a big difference. This is probably the best threads on the web regarding tank water collection for rural property, and should be required reading for all those with tank water or about to install tank water. Its not for the text book model as that's dynamic but makes you think about your system. I would change a few things for my own application. Pulpo Re: Need advice on our rainwater collection and storage syst 49Nov 05, 2012 11:55 am Some further refinements & small adjustments to reduce connections & fittings. Deleted tank 3 from 32mm pump line. Pump will draw from tank 2, or 1 as a backup. I've shown 100-50mm reducers a little clearer and level with 100mm wet pipes. Will bring 50mm pipes to surface at tank 4. Have added Alko jet pump to supply garden water via a tap off tank 4. Tank 4 can be isolated at balance line. John Link to full size image Link to full size image Re: Need advice on our rainwater collection and storage syst 50Nov 05, 2012 12:58 pm jnk40. just curious how the first flush system works. Does it require manual purging at the time of first rains after a dry period? I can understand how it works as a sediment trap but I cannot fathom the first flush aspect. I would have thought a first flush system would require a dry pipe for the first volume of water to flow into. fireflies Re: Need advice on our rainwater collection and storage syst 52Nov 05, 2012 2:59 pm hi fireflies, sorry I should've explained. My system won't actually have the first flush component of the sediment trap in the diagram above. I decided to leave it in for future reference to SaveH20's design.
In my system, Tank 4 will effectively serve as a large first flush diversion and settling tank. My wet pipes will hold +600L so it would've been impractical to drain them regularly. The wet pipes should not go stagnant in the short term as they should be pretty well free of debris due to the rainheads, sediment traps and flush velocity achieved 'horizontally' via the 50mm DWV's into tank 4. The setup has allowed me to save water whilst also reducing maintenance & costs. Tank 4 also compensates for first flush diverters not being able to be fitted at the house due to the low head. Out of wet season between long periods of rain I could elect to drain the wet pipes via the sediment trap's 40mm pipe and flush valve. This would require temporarily closing the 50mm infeed valves on tank 4. SaveH2O's sediment trap can also serve as a first flush chamber provided the tank is sited down a slope and the trap is above the tank’s water level. This will allow that part of the pipe to drain (provided you also flush the trap). John Re: Need advice on our rainwater collection and storage syst 53Nov 05, 2012 3:18 pm Pulpo I guess you will turn off the valves (for the 50mm inlets) going into tank 4 before purging the first flush system? Excellent diagram. Pulpo John Re: Need advice on our rainwater collection and storage syst 54Nov 05, 2012 4:01 pm Thanks jnk40. that makes it clearer. I'm interested as we are just in the process of doing earthworks for our shed/house and tank so am looking into best options as we will be reliant on tank water as well. Re: Need advice on our rainwater collection and storage syst 55Nov 22, 2012 9:31 am Hi John, It would be handy if you also have an Inspection Opening (I.O.) at each sediment trap. You have two choices here, you can either fit a separate fitting that would place the I.O. at either end of the 45 degree junction or you can buy an I.O. junction that has the I.O. directly above the bottom opening as per the image below. The bottom opening along the horizontal length won't be as large as the one in a 45 degree junction but the opening does slope downwards rather than have a direct fall and so it will capture most of the bed load provided the flow is laminar. The connecting elbow and taper at the bottom will be lower though. The fitting costs about $35 but that includes a cap and a removable fitting inside that seals the opening below the cap along the top horizontal section. I think that it is worth the investment. Regulations in some States also require two I.O.s. Your sediment trap drain should qualify as the second. Having the I.O. there will allow you to have a quick look inside whenever you drain the system and it will be easy to give it a quick clean if ever needed. You will need to box it with a top cover for access. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ 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: Need advice on our rainwater collection and storage syst 56Nov 27, 2012 7:21 pm Agree, would be a smart idea for the long term. If I didn't have it I would always be curious as to what was going on in the trap. I had a look at the fittings at Reece. After adding a 90 degree bend on the bottom of the IO tee junction, the trap's 100mm pipe would run about 230mm below the top wet pipe. The trench would end up 500mm deep where the trap resides. I imagine I would then slowly bring the 40mm tail to the surface. I could run it in the same straight trench as the 50mm infeeds along to tank 4. It would then pop out the small bank at the end of the tanks with a valve to drain. The total 40mm run would be about 20mts. John Re: Need advice on our rainwater collection and storage syst 57Nov 28, 2012 12:27 am Hi John, Yeah, the bit of extra depth is a drawback but it will blast out at over 120 lpm with a 1 metre head over the pipe run you quote and so any slope is no big deal. The 20 metres will only hold 25 litres. 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: Need advice on our rainwater collection and storage syst 58Dec 08, 2012 12:19 am Hi John, I thought that I would give you a recommendation at this stage about plumbing your pump to the cistern. Cistern valves are designed to cope with high pressure mains water but you will be reliant on tank water and a household pressure pump. I suggest that you fit the cistern with a 400UK063 Fluidmaster cistern valve, see below. They cost about $20. http://www.haron.com.au/fluidmaster_products.html This valve has two optional seals, a low pressure seal and a very low pressure gravity fed seal - the red one near the bottom of the page I have linked. They cost about $2.50. I have my cistern valve that draws from the pump fitted with the red gravity fed seal as I gravity feed to the cistern for probably 9 months of the year. When the pump is used (switched on), there are no problems with using the low pressure seal and I have been doing so for about 8 years now. Many people don't realise that water will flow through a pump when it is turned off and the flow path is open. 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: Need advice on our rainwater collection and storage syst 59Dec 10, 2012 4:34 pm Re above post and recommendation for the Fluidmaster cistern valve fitted with the optional gravity fed seal... John will not be able to gravity feed to the cistern as he will need his pump turned on at all times. My recommendation was to use the Fluidmaster cistern valve and the optional gravity fed seal as pumps operate with lower pressure than mains water supply as I posted. The valve & seal combination was suggested so that the pump would operate with less restriction and the cistern would fill faster. The reference to my cistern operating with both gravity feed and mains pressure was to indicate that the gravity fed seal wasn't restricted to operating only with gravity feed. I have since recommended to John that he consider fitting a header tank in the roof space to supply the cistern, something that should be easy to do as he is building. If this was sized to automatically fill at a pre set low level perhaps once a day, nearly 4,000 pump start ups would be eliminated every year. Re using a rear access junction to make a sediment trap, while this is a good idea, buying it from REECE PLUMBING is not!!!!!!!!!!! Check out the price for the same fitting from this online store. REECE PLUMBING charge about $35. It pays to Google first. http://www.pipeonline.com.au/listProduc ... S+JUNCTION 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 19783 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 31528 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 8592 |