Browse Forums Building Standards; Getting It Right! Re: Storm water 43Jul 29, 2019 8:08 am 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: Storm water 45Jul 29, 2019 10:09 am 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: Storm water 47Jul 30, 2019 8:23 pm I misunderstood, sorry. Good idea. 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: Storm water 48Feb 19, 2020 8:37 am Hi H2O After the recent rain which the first initial rain fall filled the tank. Subsequent rain falls started to pour out through slots in front of gutters and all down pipe outlets I checked the tank and this was over flowing through the top as well. As previous discussion with only one outlet it’s not enough to cope with excess, Do I go to Certifier or builder , I have no faith with builder as they are clueless in regard to BCA and As Thanks Tim Re: Storm water 49Feb 19, 2020 11:49 am Hi Tim. First a backtrack. Re the thread's previous discussions about AS 2870 and flexible joints, I had discussions with a senior person in the VBA plumbing department and was told that AS 2870 was not applicable because the pipes exiting the slab come under the BCA, not the PCA and as AS 2870 was not referenced in the BCA, it did not apply! I also argued the case for downpipes but got nowhere. The discussion became very convoluted and the twisting and turning explanations frazzled my brain but it seems that there are problems with the intended application of AS 2870 compliance that no one appears to be in a position to fix. My brain is still frazzled from the discussion and I can't explain further in detail. Maybe someone else can but there does appear to be widespread belief in a required use of some AS 2870 Standards that have no legislated mandate. Tim65 After the recent rain which the first initial rain fall filled the tank. Subsequent rain falls started to pour out through slots in front of gutters and all down pipe outlets I checked the tank and this was over flowing through the top as well. As previous discussion with only one outlet it’s not enough to cope with excess, A recap: Because the water tank is part of the 'loop' that connects the roof drainage to the stormwater system, the pipework is subject to the same mandated compliance. This is black and white. The severe non adherence to compliance has also made the roof drainage non compliant. Your situation also highlights the folly of building surveyors signing off on things they know nothing about by accepting a plumber's certificate of compliance as proof of compliance. Have you formally lodged a complaint with the (unfortunately useless) Department of Fair Trading (DFT) about the severity of the non compliant plumbing? Tim65 Do I go to Certifier or builder , I have no faith with builder as they are clueless in regard to BCA and As You haven't got anywhere with the builder or plumber in the past and the certifier will just say it is to do with the plumber but the DFT should (if competent) make the plumber rectify the plumbing disaster although I would insist on having another plumber do the work. A huge problem is that you have an archaic standard wet (charged) rainwater harvesting system and these have many inherent problems, mainly because the people who install them don't know what they are doing. Your biggest problem is that such systems divert downpipes to the tank which means that none of your downpipes are connected to a stormwater system and so if a number of the downpipes are taken out of the system, a 150mm stormwater pipe also needs to be laid for the decommissioned downpipes to connect to. Would the laying of this pipe cause disruption to established paths, garden beds, other structures etc? Unfortunately, there is no other fix. The single 90mm overflow pipe will almost certainly be the same size all the way which is just extreme high level incompetence by all parties involved. The two 90mm (86.2mm ID) pipes currently diverted to the tank are hopelessly undersized and there is no way that hydraulic calculations could possibly have been done. The plumber has to be grossly incompetent to have plumbed them and issued a certificate of compliance and he should be reported, what other grossly incompetent work has he done? Heaps I'll bet. Are you able to post photos (not close up) of the tank's overflow pipe and wet systems supply pipes where they 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: Storm water 50Feb 19, 2020 9:16 pm SaveH2O Hi Tim. First a backtrack. Re the thread's previous discussions about AS 2870 and flexible joints, I had discussions with a senior person in the VBA plumbing department and was told that AS 2870 was not applicable because the pipes exiting the slab come under the BCA, not the PCA and as AS 2870 was not referenced in the BCA, it did not apply! I also argued the case for downpipes but got nowhere. The discussion became very convoluted and the twisting and turning explanations frazzled my brain but it seems that there are problems with the intended application of AS 2870 compliance that no one appears to be in a position to fix. My brain is still frazzled from the discussion and I can't explain further in detail. Maybe someone else can but there does appear to be widespread belief in a required use of some AS 2870 Standards that have no legislated mandate. Tim65 After the recent rain which the first initial rain fall filled the tank. Subsequent rain falls started to pour out through slots in front of gutters and all down pipe outlets I checked the tank and this was over flowing through the top as well. As previous discussion with only one outlet it’s not enough to cope with excess, A recap: Because the water tank is part of the 'loop' that connects the roof drainage to the stormwater system, the pipework is subject to the same mandated compliance. This is black and white. The severe non adherence to compliance has also made the roof drainage non compliant. Your situation also highlights the folly of building surveyors signing off on things they know nothing about by accepting a plumber's certificate of compliance as proof of compliance. Have you formally lodged a complaint with the (unfortunately useless) Department of Fair Trading (DFT) about the severity of the non compliant plumbing? Tim65 Do I go to Certifier or builder , I have no faith with builder as they are clueless in regard to BCA and As You haven't got anywhere with the builder or plumber in the past and the certifier will just say it is to do with the plumber but the DFT should (if competent) make the plumber rectify the plumbing disaster although I would insist on having another plumber do the work. A huge problem is that you have an archaic standard wet (charged) rainwater harvesting system and these have many inherent problems, mainly because the people who install them don't know what they are doing. Your biggest problem is that such systems divert downpipes to the tank which means that none of your downpipes are connected to a stormwater system and so if a number of the downpipes are taken out of the system, a 150mm stormwater pipe also needs to be laid for the decommissioned downpipes to connect to. Would the laying of this pipe cause disruption to established paths, garden beds, other structures etc? Unfortunately, there is no other fix. The single 90mm overflow pipe will almost certainly be the same size all the way which is just extreme high level incompetence by all parties involved. The two 90mm (86.2mm ID) pipes currently diverted to the tank are hopelessly undersized and there is no way that hydraulic calculations could possibly have been done. The plumber has to be grossly incompetent to have plumbed them and issued a certificate of compliance and he should be reported, what other grossly incompetent work has he done? Heaps I'll bet. Are you able to post photos (not close up) of the tank's overflow pipe and wet systems supply pipes where they discharge? Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Storm water 51Feb 19, 2020 9:16 pm Tim65 SaveH2O Hi Tim. First a backtrack. Re the thread's previous discussions about AS 2870 and flexible joints, I had discussions with a senior person in the VBA plumbing department and was told that AS 2870 was not applicable because the pipes exiting the slab come under the BCA, not the PCA and as AS 2870 was not referenced in the BCA, it did not apply! I also argued the case for downpipes but got nowhere. The discussion became very convoluted and the twisting and turning explanations frazzled my brain but it seems that there are problems with the intended application of AS 2870 compliance that no one appears to be in a position to fix. My brain is still frazzled from the discussion and I can't explain further in detail. Maybe someone else can but there does appear to be widespread belief in a required use of some AS 2870 Standards that have no legislated mandate. Tim65 After the recent rain which the first initial rain fall filled the tank. Subsequent rain falls started to pour out through slots in front of gutters and all down pipe outlets I checked the tank and this was over flowing through the top as well. As previous discussion with only one outlet it’s not enough to cope with excess, A recap: Because the water tank is part of the 'loop' that connects the roof drainage to the stormwater system, the pipework is subject to the same mandated compliance. This is black and white. The severe non adherence to compliance has also made the roof drainage non compliant. Your situation also highlights the folly of building surveyors signing off on things they know nothing about by accepting a plumber's certificate of compliance as proof of compliance. Have you formally lodged a complaint with the (unfortunately useless) Department of Fair Trading (DFT) about the severity of the non compliant plumbing? Tim65 Do I go to Certifier or builder , I have no faith with builder as they are clueless in regard to BCA and As You haven't got anywhere with the builder or plumber in the past and the certifier will just say it is to do with the plumber but the DFT should (if competent) make the plumber rectify the plumbing disaster although I would insist on having another plumber do the work. A huge problem is that you have an archaic standard wet (charged) rainwater harvesting system and these have many inherent problems, mainly because the people who install them don't know what they are doing. Your biggest problem is that such systems divert downpipes to the tank which means that none of your downpipes are connected to a stormwater system and so if a number of the downpipes are taken out of the system, a 150mm stormwater pipe also needs to be laid for the decommissioned downpipes to connect to. Would the laying of this pipe cause disruption to established paths, garden beds, other structures etc? Unfortunately, there is no other fix. The single 90mm overflow pipe will almost certainly be the same size all the way which is just extreme high level incompetence by all parties involved. The two 90mm (86.2mm ID) pipes currently diverted to the tank are hopelessly undersized and there is no way that hydraulic calculations could possibly have been done. The plumber has to be grossly incompetent to have plumbed them and issued a certificate of compliance and he should be reported, what other grossly incompetent work has he done? Heaps I'll bet. Are you able to post photos (not close up) of the tank's overflow pipe and wet systems supply pipes where they discharge? Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Storm water 52Feb 19, 2020 9:33 pm AS2870 does have a legislative mandate as seen in the decision with Metricon v softley. The decision was based on non compliance including quoted sections 5.5.3a, 6.6c, 5.2.1 of AS2870 which relates to site drainage. Re: Storm water 53Feb 19, 2020 10:27 pm Hi insider, I have edited what I posted last night as I have found my notes of the discussion with the VBA. The senior VBA person I spoke to said that because sewer pipes come from the slab, they are included in the NCC building section (BCA) where it states that the footing or slab is constructed in accordance with AS 2870 whereas stormwater is in plumbing and AS 2870 is not referenced. He also quoted Clause 5.6 and said that it was up to the plumber to decide what was needed to meet the performance requirements in the NCC but there is no requirement for AS 2870 to be used. He also read the AS 5.6 Clause and it didn’t reference AS 2870. He did say however that AS/NZS 3500.2 Clause 5.6 could cover the proper installation of plumbing or drainage installations and that the Building Surveyor would check their work but when I said that Building Surveyors don’t check plumbing work because they consider the compliance certificate as proof, he agreed with me. AS/NZS 3500.2 Clause 5.6-“Drains in other than stable ground” Clause 5.6 Prior to the commencement of work, ground conditions shall be assessed by a suitably qualified expert. Where ground conditions may affect the performance of any plumbing or drainage installation, the method to protect the installation shall be determined by a suitably qualified expert. Note however that “drains” is taken to refer to sewer, not stormwater. Unless an AS has been legislated or included in a contract, it has no legal standing. A problem has always been that when I ask the VBA for a ruling in writing, I have only ever had it given verbally except when dealing with one excellent senior technical advisor who I won't name here but I will PM you his name. You may know him. 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: Storm water 54Feb 20, 2020 5:42 am Thanks for your reply H2o 1st photo Top pipe is in Feed from down pipes 3No and lower is out let to Swale drain at front of house 2nd photo is in let from remaining 9 down pipes 1 down pipe at front was missed and they connected it to the out let pipe direct to Swale drain direct or more water would have been going to tank ( Apox 35m2 roof area ) Re: Storm water 55Feb 20, 2020 1:41 pm Hi Tim. Well, things are clearer now. The inflow wet system pipes are 100mm, not 90mm as originally thought. The overflow pipe is also 100mm. The tank almost certainly would NOT have been installed by the builder's contracted plumber as this would have been done by installers employed by the water tank supplier. Looking at the installation, I believe that the supplier would have been Kingspan, formerly Tankworks. The two 100mm pipes (I am assuming that there are 2 separate pipes) that drain the downpipes are sufficient to drain the roof area as normal roof drainage requirements provided they drain near equal roof areas but it's now my understanding that the pipe in the first photo connects to 3 downpipes and the pipe in the second photo connects to 9 downpipes! If so, it is extraordinary that the plumber has done this. For now I will assume the 3 DP and 9 DP scenario but can you confirm or otherwise thanks? Someone has designed the stormwater pipework but even if it wasn't the plumber, the plumber should not have plumbed the pipes the way he has and at the very least, he should have known that one pipe serving 9 downpipes would have inadequate hydraulic head to be able to drain to a water tank. I estimate the tank to be about 1.8 m high which probably gives a working head of 0.6 metre. The communication between 9 downpipes with the 100mm pipe generates a lot of friction loss and the maximum flow rate would be no more than 540 lpm assuming 100 metres of pipe (with the friction losses added as equivalent pipe length) and a 1 metre head. For the roof area that the 9 downpipes would drain to a single pipe, the wet system's flow capacity is clearly inadequate. The wet system inflow pipes have a meshed basket inside the tank. This holds larger debris flushed up from the wet system, you need to access this and clean it. See the link below. https://www.youtube.com/watch?v=U2NeOgH_bSY Rubbish should not enter the wet system, this method merely fills the requirement to have water entering a tank to first pass through a mosquito proof screen. It does nothing to divert bird droppings and organic matter, much of it remains in the wet system underground pipe, making the water anaerobic as it decomposes. The upper pipe continues downwards and exits as an overflow pipe, allowing the excess water in a full tank to pass through the upper mesh which also flushes out the mesh cylinder. See diagram in the brochure linked below. https://kingspanwater.com.au/wp-content/uploads/2015/10/High-flow_Specs-d6.pdf You will also see the guy in the video tap on a pipe, unfortunately this is a first flush diverter uselessly fitted to the top of a wet system vertical riser. When it next rains, the first flush diverter will fill with the settled water in the riser while the first flush is in the downpipe(s) at the other end of the wet system. This is how unknowledgeable water tank installers and many plumbers install first flush diverters...totally useless and a waste of money and water. Fortunately you don't have these. What you also don't have is a second overflow pipe as you have said and you can see the overflow pipe outlet capped behind the wet system's vertical riser. This is deliberate and words fail me! You need to contact the builder and tell him to get some knowledgeable plumbers out to rectify the roof drainage as well as the rainwater harvesting system. I would also be writing a formal complaint about severe non compliance to the DFT. One other thing you need to do is check whether the submersible pump (it will be a Davey) draws water from its base and if so, whether it is raised off the tank's floor so that it doesn't vacuum sediment. I also don't like pumps sitting directly under where the water falls in from a height as it can resuspend sediment and feed air bubbles to the pump, even at moderate water levels. https://www.youtube.com/watch?v=ULj6Ar2ncLE&t=207s Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ 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: Storm water 56Feb 20, 2020 5:44 pm SaveH2O Hi Tim. Well, things are clearer now. The inflow wet system pipes are 100mm, not 90mm as originally thought. The overflow pipe is also 100mm. The tank almost certainly would NOT have been installed by the builder's contracted plumber as this would have been done by installers employed by the water tank supplier. Looking at the installation, I believe that the supplier would have been Kingspan, formerly Tankworks. The two 100mm pipes (I am assuming that there are 2 separate pipes) that drain the downpipes are sufficient to drain the roof area as normal roof drainage requirements provided they drain near equal roof areas but it's now my understanding that the pipe in the first photo connects to 3 downpipes and the pipe in the second photo connects to 9 downpipes! If so, it is extraordinary that the plumber has done this. For now I will assume the 3 DP and 9 DP scenario but can you confirm or otherwise thanks? Someone has designed the stormwater pipework but even if it wasn't the plumber, the plumber should not have plumbed the pipes the way he has and at the very least, he should have known that one pipe serving 9 downpipes would have inadequate hydraulic head to be able to drain to a water tank. I estimate the tank to be about 1.8 m high which probably gives a working head of 0.6 metre. The communication between 9 downpipes with the 100mm pipe generates a lot of friction loss and the maximum flow rate would be no more than 540 lpm assuming 100 metres of pipe (with the friction losses added as equivalent pipe length) and a 1 metre head. For the roof area that the 9 downpipes would drain to a single pipe, the wet system's flow capacity is clearly inadequate. The wet system inflow pipes have a meshed basket inside the tank. This holds larger debris flushed up from the wet system, you need to access this and clean it. See the link below. https://www.youtube.com/watch?v=U2NeOgH_bSY Rubbish should not enter the wet system, this method merely fills the requirement to have water entering a tank to first pass through a mosquito proof screen. It does nothing to divert bird droppings and organic matter, much of it remains in the wet system underground pipe, making the water anaerobic as it decomposes. The upper pipe continues downwards and exits as an overflow pipe, allowing the excess water in a full tank to pass through the upper mesh which also flushes out the mesh cylinder. See diagram in the brochure linked below. https://kingspanwater.com.au/wp-content/uploads/2015/10/High-flow_Specs-d6.pdf You will also see the guy in the video tap on a pipe, unfortunately this is a first flush diverter uselessly fitted to the top of a wet system vertical riser. When it next rains, the first flush diverter will fill with the settled water in the riser while the first flush is in the downpipe(s) at the other end of the wet system. This is how unknowledgeable water tank installers and many plumbers install first flush diverters...totally useless and a waste of money and water. Fortunately you don't have these. What you also don't have is a second overflow pipe as you have said and you can see the overflow pipe outlet capped behind the wet system's vertical riser. This is deliberate and words fail me! You need to contact the builder and tell him to get some knowledgeable plumbers out to rectify the roof drainage as well as the rainwater harvesting system. I would also be writing a formal complaint about severe non compliance to the DFT. One other thing you need to do is check whether the submersible pump (it will be a Davey) draws water from its base and if so, whether it is raised off the tank's floor so that it doesn't vacuum sediment. I also don't like pumps sitting directly under where the water falls in from a height as it can resuspend sediment and feed air bubbles to the pump, even at moderate water levels. https://www.youtube.com/watch?v=ULj6Ar2ncLE&t=207s Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Just doubled checked drawings and actual as built We have 7 down pipes which connect to Wet system riser pipe covering the over flow pipe and 3 coming in via the other wet system riser I am 99.9% certain the builders plumber did all this work not kings span Total roof area is 420.1 as marked on DA plans With a 22.5 pitch We actually upgraded to a smooth line gutter from the standard ( larger) We were charged extra fir water tank as they said it needed to be 3586 ltr tank original was a 3000 ltr Re: Storm water 58Feb 20, 2020 7:22 pm Tim65 Just doubled checked drawings and actual as built We have 7 down pipes which connect to Wet system riser pipe covering the over flow pipe and 3 coming in via the other wet system riser I am 99.9% certain the builders plumber did all this work not kings span Total roof area is 420.1 as marked on DA plans. The figures below are obviously ball park. Minus the one downpipe the plumber missed (35 sq m) leaves 395.1 sq m of roof drained to the tank by 10 DPs, an average of 39.5 sq m per DP. If we use the average figure, 7 DPs will drain a total roof area of 276.5 sq m. During your area's 1:20 ARI, this will be a minimum 691 mm/min average over the minimum 5 minute rain intensity duration the pipe is required to drain but as we already know when the rain recently demonstrated, that is but a pipedream. This issue plus blocking off one overflow pipe just staggers me. What is your next move? 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: Storm water 59Feb 20, 2020 8:05 pm Tim65 Just reading link on tank It states that “ Overflow diameter should match inflow pipe diameter.” So if 2 inflow pipes fitted there should be 2 overflow pipes ? For this system, yes but the overflow capacity isn't stated in the brochure. Unfortunately, there isn't a tank manufacturer I know of that quotes overflow capacities and plumbers don't know. Your system absolutely needs both overflows connected as already demonstrated. 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: Storm water 60Feb 20, 2020 8:48 pm SaveH2O Tim65 Just doubled checked drawings and actual as built We have 7 down pipes which connect to Wet system riser pipe covering the over flow pipe and 3 coming in via the other wet system riser I am 99.9% certain the builders plumber did all this work not kings span Total roof area is 420.1 as marked on DA plans. The figures below are obviously ball park. Minus the one downpipe the plumber missed (35 sq m) leaves 395.1 sq m of roof drained to the tank by 10 DPs, an average of 39.5 sq m per DP. If we use the average figure, 7 DPs will drain a total roof area of 276.5 sq m. During your area's 1:20 ARI, this will be a minimum 691 mm/min average over the minimum 5 minute rain intensity duration the pipe is required to drain but as we already know when the rain recently demonstrated, that is but a pipedream. This issue plus blocking off one overflow pipe just staggers me. What is your next move? I am going to draft an email over weekend to builder, Certifier and also fair trades making formal complaint and see what comes back I have a feeling it’s going to be drawn out affair. Many thanks for your help much appreciated Hello I am developing 2 side by side units. Wish someone can help me on the following questions 1) Which stage should be the storm water pipe installed during the new… 0 8283 If you need to be able to access these then you may need to dig them out and cut them so you can add a socket and a riser to the required height. We normally add a… 1 7148 Thanks for that, the PVC pipe is still about 40cm below ground level and it sticks out of the sand with no end cap or anything on it just open pipe, is this the finished… 2 11013 |