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About iSelfBuild

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    Dumfries & Lancashire

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  1. That makes 100% logic 😊 But how do you calculate the volume or should I say displacement of gravel? The chap at the top (screen print) had Aggregate void at 30%... So 1.32 m3 x 3.33333* = 4.39 m3 I would say that is a very suitable sized soakaway???
  2. Thank you, I'm still a bit confused. This calculation seems to suggest 1.32m3 is big enough but it doesn't say if this is for crate systems where there is a big void or if it's for granular rock infilled soakaways.
  3. Any ideas how I take the m3 area and convert that into a real life sized drainage pit? I can't get my head round why the one I posted initially was specified at 1m x 10m
  4. Can anyone confirm I am working out the area correctly? 1m x 3m - 50% depth would be 0.5m, the base is excluded so it is 0.5 x 1+1+3+3 = 4m2 f = (1/VP) / 1000 or 0.00003367 = (1/29.7) / 1000 For 100m2 area to be drained: The soakaways may be sized using the following simplified formulae derived from BRE Digest 365: (A x 0.0145) – (a x f x 900) = S (100m2 x 0.0145) - (4 x 0.00003367 x 900) = 1.328m3 So how do I then take this 1.328m3 area and size the soak away considering it will be filled with clean rock.
  5. Thanks. So a - is the internal surface area of the soakaway to 50% effective depth, excluding the base in m2. So say 1m x 3m is... 0.5 x 1+1+3+3. So 4m2? Assuming the top isn't considered as well as the base of the pit.
  6. Yes there is a long winded way for f value, then there is thankfully the method of doing a VP value and converting it. I just don't get the whole a = assumed bit as that completely changes the final outcome so is open to manipulation?
  7. Thanks is this the simplified formula? I'm assuming I calculate VP the same way as in drainage fields? The soakaways may be sized using the following simplified formulae derived from BRE Digest 365: (A x 0.0145) – (a x f x 900) = S Where - A is the area to be drained in m2. a - is the internal surface area of the soakaway to 50% effective depth, excluding the base in m2. This has to be assumed for initial calculation purposes. f - is the soil infiltration rate, in m/s, determined in accordance with clause 3.9.1. This calculation produces Vp in secs/mm [conversion = (1/Vp) /1000]. S - is the required storage in m3. I know the VP was 29.7 for the drainage field, so I do a test like that and convert it into a f value? = (1/Vp) /1000]. a is the internal surface area of the soak away? I'm a bit confused by it being assumed?
  8. I'm a little confused on this one. I have done a fair few percolation tests in the past in order to design drainage fields for treatment plants. Area = Population x Percolation Value (Time from 75% down to 25%) X 0.2 (secondary treatment) / A = P x Vp x 0.2 Calculating the VP is a dead easy process. I have attached the results of one of my rainwater soakaways on a site, I never did the calculations for this or the soil infiltration test for them. How is the soil infiltration (f) derived/performed? Once I have the figure how do I replicate this sheet I have too?
  9. I quite liked living in a touring caravan for 16 months haha. The saving grace was ripping out the gas fire and fitting a micro log burner.
  10. I'm interested to see them. Especially the timber ring beam construction. What dimensions where the outer timber for that?
  11. To be honest John, I don't think anyone up there knows what's going on and that includes SW and me! The supply comes from the farm so that could be why it's 90mm? No the Hydrants at the lower part are directly off the 90mm. Aditional hydrants at the top of the site... I'm guessing that's coming off a 50mm from the header tank.
  12. Nope. 90mm comes into the site, no meters what so ever. This stops in 90mm as soon as it comes into the site. It then comes off in 32mm supply pipes (from memory) One comes off into a break tank for the pumped supply to the header, one just comes off for the mains supply to the header - which it also tees off at my parents plot for their supply. Absolutely no meters on any of that. Not sure what the pressure is rated at on the header tank system, I have stayed in my neighbours chalet once and it was not terrible but not high pressured for sure. My parents 700 litre tank and pump - we can set that all the way up to 9 bar pressure so works pretty great in my opinion. I'm likely going to fit a dab e sybox mini in my log cabin if the pressure is not great when I test it. (My log cabin is served off the header tank system) there is no issue with flow and the pressure seems OK, but haven't tested it with a gauge yet. The only place SW are putting meters are where it feeds into each plot boundary.
  13. Scottish Water. There is 7 chalets on the pumped header scheme. Then 1 chalet (my parents on just the mains flow pipework) So 300mm from the 90mm mains, all the way up to the header tank. 25m head. Then each plot is at varied distance from the header tank with at least 10m of head of pressure from the header tank.
  14. There is fire hydrants at the bottom branching off the 90mm mains. Then there is fire hydrants branching off the downward supply pipe off the header tank opposite our plots. Never liked the whole set up to be honest and I had no involvement in it's design. It would be about 300m, but it's pointless to do anything else now. It works well both on the pumped header tank system and on our mains flow (sporadic flow and low pressure - but then held in tank in the lodge and pressurised system)
  15. I think it's about 300m from the 90mm Scotish water mains to our sites - there is no meter down there though. They are just metering it at each property where they take it out of the header tank.