Hi.
How much head room is needed for a wet system rain water tank.
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Thanks in advance
Kev
Browse Forums General Discussion Re: Wet charged systen 2Sep 27, 2020 11:13 pm It depends on the maximum flow of water through the pipe and the pipe's size and length. 3in1 Supadiverta. Rainwater Harvesting Best Practice using siphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost, siphonic, eaves gutter overflow solution. Re: Wet charged systen 3Sep 27, 2020 11:46 pm [quote="SaveH2O":20iiato4]It depends on the maximum flow of water through the pipe and the pipe's size and length.[/quote:20iiato4] Thanks for the quick reply, i appreciate it. I've got 10 down pipes in all. 7 on one run and 3 the front of the house. 80mm down pipe to 90mm and into the 2x 4000l tanks for detention, then up 400mm onto the street. No first flush or anyway to get the water out. It just doesnt seem right. [img:20iiato4]https://forum.homeone.com.au/u/75171_1601214921.png[/img:20iiato4] Re: Wet charged systen 4Sep 28, 2020 12:03 am They are all 80mm downpipes? Do the 7 x 80mm downpipes connect to a single charged 90mm pvc stormwater pipe that diverts to a vertical riser at the tank? If so, do you know the approximate total roof area harvested by those 7 downpipes? How many downpipes divert to the vertical riser shown in the photo? 3in1 Supadiverta. Rainwater Harvesting Best Practice using siphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost, siphonic, eaves gutter overflow solution. Re: Wet charged systen 5Sep 28, 2020 12:09 am ![]() They are all 80mm downpipes? Do the 7 x 80mm downpipes connect to a single charged 90mm pvc stormwater pipe that diverts to a vertical riser at the tank? If so, do you know the approximate total roof area harvested by those 7 downpipes? How many downpipes divert to the vertical riser shown in the photo? EMMERSON MOD CONSOLE SILVER CUP HOLDERS 10292 STA2 The 7 x 80mm all connect to a single charged 90mm which runs around the side and back of house which then picks up the 3 x 80mm down pipes running from the front of the house at the vertical riser and into the tank. Approx roof 250sqm. Hope this makes sense Re: Wet charged systen 6Sep 28, 2020 12:22 am ![]() They are all 80mm downpipes? Do the 7 x 80mm downpipes connect to a single charged 90mm pvc stormwater pipe that diverts to a vertical riser at the tank? If so, do you know the approximate total roof area harvested by those 7 downpipes? How many downpipes divert to the vertical riser shown in the photo? I'll take photos tomorrow and forward them if that's ok. Really appreciate your advice on this matter. It's a new build subdivision and I haven't signed off yet as I'm concerned about the wet system. Kind regards Kev Re: Wet charged systen 7Sep 28, 2020 1:02 am ![]() The 7 x 80mm all connect to a single charged 90mm which runs around the side and back of house which then picks up the 3 x 80mm down pipes running from the front of the house at the vertical riser and into the tank. Approx roof 250sqm. Hope this makes sense OMG!!! That is beyond incompetence. Eaves gutter roof drainage compliance factors your area's 1:20 Average Recurrence Interval (ARI) to determine your gutter and downpipe sizes. If you let me know your region, I can look up your ARI and work out the minimum flow rate that would be expected of the 90mm wet system pipe but it is waaaaay inadequate. 90mm pvc SN2 stormwater pipe is measured as an outside diameter, the inside diameter is 86.2mm which gives it a volume of 5.836 litres per metre. A velocity of 1 metre per second = 351.8 litres per minute. Perth's 1:20 ARI is 140 mm/h which is based on an average rain intensity of 2.33 mm/minute over a 5 minute duration. If you are in Perth, the minimum flow rate through that 90mm pvc stormwater pipe would be 2.33 x 250 = 583 lpm. This also equates to a flow velocity of 1.65 metres per second. Crazy! It is obvious that the system was designed by someone who lacked knowledge in the art and who also neglected to do hydraulic calculations. I can see your stormwater plan in your profile's photo list but it is difficult to read. I can however see that there are two outlets but no mention of the council's PSD or the lower discharge orifice size. Looking at the photo, you probably have little more than 200mm hydraulic head which is totally inadequate! To post a quote, you click the upper reply above the Facebook and Twitter icons to bring up the full editor. This will show the full quote that you are replying to and you can edit out what you don't need to repeat. Your reply is then typed below the quote box. To post a photo, just click Upload Photos. Pressing the orange Reply box doesn't bring up full editor. 3in1 Supadiverta. Rainwater Harvesting Best Practice using siphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost, siphonic, eaves gutter overflow solution. Re: Wet charged systen 8Sep 28, 2020 8:41 am I have just done a quick calculation. Let's imagine that the downpipe in the photo is a larger 90mm pvc stormwater pipe, the pipe length which includes the 90 degree elbows as equivalent pipe lengths is a total pipe length of 17 metres, there is 220mm head and all of the roof water is miraculously diverted to that one downpipe, the maximum discharge rate into the tank will be approximately 380 lpm. Friction losses (high turbulence at the 90 degree interface) through a tee's branch at the majority of other downpipes are about 50% greater than those at a 90 degree elbow. 3in1 Supadiverta. Rainwater Harvesting Best Practice using siphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost, siphonic, eaves gutter overflow solution. Re: Wet charged systen 9Sep 28, 2020 8:51 am Blimey, Lucky i posted on this forum and you replied. Thanks so much. The discharge from the tanks up to the road is a 150mm pipe. Ill try and get as much detail forwarded once i get the hang of this. Can we post pdf file on here Re: Wet charged systen 10Sep 28, 2020 9:01 am I just tried to post a pdf file as a trial run but they didn't show in my documents list. Maybe someone else knows. Make sure you delete any private information. 3in1 Supadiverta. Rainwater Harvesting Best Practice using siphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost, siphonic, eaves gutter overflow solution. Re: Wet charged systen 18Sep 28, 2020 2:49 pm ![]() I have just done a quick calculation. Let's imagine that the downpipe in the photo is a larger 90mm pvc stormwater pipe, the pipe length which includes the 90 degree elbows as equivalent pipe lengths is a total pipe length of 17 metres, there is 220mm head and all of the roof water is miraculously diverted to that one downpipe, the maximum discharge rate into the tank will be approximately 380 lpm. Friction losses (high turbulence at the 90 degree interface) through a tee's branch at the majority of other downpipes are about 50% greater than those at a 90 degree elbow. From the rear of the property 6 x 80mm down pipes connect to the 90mm then to the tank.Approx 40m run At the front there are 4 x 80mm downpipes that connect to the 90mm then joins the 90mm at the tank. Approx 25m run I live in Greenmount WA I've measured the head room at 145mm. From the bottom of the gutter to the top of the intent pipe. Hope this helps... Re: Wet charged systen 19Sep 28, 2020 3:07 pm ![]() ![]() I have just done a quick calculation. Let's imagine that the downpipe in the photo is a larger 90mm pvc stormwater pipe, the pipe length which includes the 90 degree elbows as equivalent pipe lengths is a total pipe length of 17 metres, there is 220mm head and all of the roof water is miraculously diverted to that one downpipe, the maximum discharge rate into the tank will be approximately 380 lpm. Friction losses (high turbulence at the 90 degree interface) through a tee's branch at the majority of other downpipes are about 50% greater than those at a 90 degree elbow. From the rear of the property 6 x 80mm down pipes connect to the 90mm then to the tank.Approx 40m run At the front there are 4 x 80mm downpipes that connect to the 90mm then joins the 90mm at the tank. Approx 25m run I live in Greenmount WA I've measured the head room at 145mm. From the bottom of the gutter to the top of the intent pipe. Hope this helps... Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Hi all Long time reader here, first time poster. My Mum bought a house a few years back and the downpipes off the bullnose verandah basically just went about a meter… 0 8482 DIY, Home Maintenance & Repair Thanks again. Yes they both share the same run and I get what you mean. Will involve a bit of digging but that’s ok. I’ll be cutting the tank up because it would… 4 9731 |