Browse Forums General Discussion 1 Jun 22, 2021 9:23 pm Looking for advice please - and apologies, I don't know much about plumbing requirements. We have had an extension/renovation to our home and have had to install a charged system for the downpipes to connect to. We specified three months ago that we'd like all the downpipes black and the first ones that went on (on the street facade) were. I've noticed today that two big round WHITE pipes were installed down the back. I hate them. I asked my builder and he said that they can't be changed. Before I go a bit nuts - can someone help out by telling me if these pipes are the only type that can be used on a charged system (rather than the black colourbond rectangular ones used in the photo with the red arrow)? And how hard they would be to change? Many thanks in advance. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Downpipe requirements for a charged system - help please 2Jun 22, 2021 9:35 pm You need pvc downpipes for a charged system for very obvious reasons. Pvc stormwater pipes are white and 100mm pvc DWV pipes are grey. You can paint pvc any colour but black is not usual for a charged system if the downpipe are to retain water but you haven't said where the water is being diverted to and/or what the respective levels are. 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: Downpipe requirements for a charged system - help please 3Jun 22, 2021 10:28 pm Thanks. So am I right in guessing that the grey DWV pipes are more expensive than the white stormwater? You mention that black isn’t common for charged systems - is there a reason for this? (We just wanted them to blend in more). The water is being diverted to a tank with pump and all down pipes are doing to this tank under the ground. Re: Downpipe requirements for a charged system - help please 4Jun 22, 2021 11:00 pm 90mm stormwater pipe has a wall thickness of 2mm, an internal diameter of 86.2mm and holds 5.8 L/metre. The 100mm DWV pipe has a wall thickness of 4mm, an internal diameter of 104mm and holds 8.5 L/m. The DWV pipe is dearer but considering its strength and 46% greater volume, it really is a cheap pipe. Your downpipes won't retain water and so painting them with on outdoor dark paint won't be a problem. You also most probably don't need pvc downpipes if the Colorbond downpipes can be sealed to the sub surface PVC pipe. The plumber just needs to do some hydraulic calculations to determine the sub surface pvc pipe's required head. Someone with NZ experience can advise further. Underground tanks need special consideration as you don't want a build up of hard to remove sediment inside the tank. Fitting a sediment trap to a non turbulent section of pipe close to the tank should be a prerequisite. The one below is my design, is made from off the shelf parts and is very effective. We don't use the pipe reducer any more, an invert taper is smoother and there are no blank sections where sediment can accumulate. The discharge pipe is size reduced to increase the discharge velocity as well as save money and water. Because the tank is underground, the discharge pipe will need to discharge at a low point on the property to work. . Like ⋅ 5 comments ⋅ 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: Downpipe requirements for a charged system - help please 5Jun 23, 2021 7:11 am Sorry, I wrote the last post not particularly clear. The tank itself is above ground, but all the down pipes etc feed into it via pipes that are underground. I really appreciate your help - it’s hard to navigate the situation when you have no plumbing experience and the builder and plumber aren’t exactly forthcoming with options. Re: Downpipe requirements for a charged system - help please 6Jun 23, 2021 7:50 am You have to have pvc pipes to service the above ground tank because the downpipes will retain water. Black paint, when exposed to the sun, will heat the retained water in the downpipes which isn't a good idea but basically you can paint whatever colour you like. If the downpipes are white and not grey, they will be 90mm pvc stormwater pipes. PVC stormwater pipes MUST be painted or otherwise protected because they are not UV stabilised. I would only use DWV sub surface charged pipes but the selection only depends on the required (water) carrying capacity and flow rate rather than a common sense approach as to which of the two pipes is structurally most suitable. Many builders/plumbers cheap out and use flimsy 90mm PVC stormwater pipe but it is false economy. Are you on reactive soil? The sediment trap is still highly recommended for capturing bed load to substantially reduce tank sedimentation and it can be used very effectively with the above ground flush outlet due to head pressure being provided by the retained water in the downpipes and the vertical riser at the tank. I wrote in my last post that pvc stormwater pipe is not uv stabilised but DWV pipe is. I have since deleted it because while I know some manufacturers such as Marley in NZ make UV stabilised DWV pipe, other manufacturers may not and their websites don't provide much information. I have assumed because of your member's name that you are NZ based. 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: Downpipe requirements for a charged system - help please 8Jun 23, 2021 10:03 am LouNZ Thank you so much for answering these questions! I’m actually in Melbourne (but am a NZ’er at heart). I will try and get the plumber to chat today. Of interest... The Victorian Building Authority (VBA) Technical Solution Sheet 4:05 recommended the use of sub surface DWV pipes for charged rainwater systems but they never mandated it. I have just checked the list of VBA Technical Solution Sheets and 4:05 has been deleted.....(big breath) not corrected of its wrong information after many years but deleted!!! https://www.vba.vic.gov.au/plumbing/resources The 2015 thread linked below that discusses 4:05 and associated matters may interest you. viewtopic.php?f=3&t=89324 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 19473 Building Standards; Getting It Right! It's all good. You can get both wye piece and the coupling with or without thread. The cost difference is negligible and means the plumber only has to carry the single… 1 4853 |