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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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Required drop for toilet outflow
Hi group...
My Dad currently has an en-suite bathroom powered by a macerator. However he wishes to convert this to a normal flush only, but is concerned about the required fall for the waste pipe. Does anybody know what the required angle of elevation is for the waste pipe of a flush toilet? thanks to anyone who takes the trouble to respond. regards paul |
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Required drop for toilet outflow
The Natural Philosopher wrote:
grimmy wrote: Hi group... My Dad currently has an en-suite bathroom powered by a macerator. However he wishes to convert this to a normal flush only, but is concerned about the required fall for the waste pipe. Does anybody know what the required angle of elevation is for the waste pipe of a flush toilet? 1:100 minuimum 1:60 ideal from memory. There's other issues as well- best consult an architect or decent builder, or look up the building regs...you need biogger pipes than the macerator as well, and where they join the downpipe is subject to issues to avoid blowback into the bath etc :-) thanks to anyone who takes the trouble to respond. regards paul Standard fittings, (branches, bends etc) all have 92.5 or 87.5 degree angles so I assume the fall should be 2.5 degrees. Bob |
#3
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Required drop for toilet outflow
Bob Minchin wrote:
The Natural Philosopher wrote: grimmy wrote: Hi group... My Dad currently has an en-suite bathroom powered by a macerator. However he wishes to convert this to a normal flush only, but is concerned about the required fall for the waste pipe. Does anybody know what the required angle of elevation is for the waste pipe of a flush toilet? 1:100 minuimum 1:60 ideal from memory. There's other issues as well- best consult an architect or decent builder, or look up the building regs...you need biogger pipes than the macerator as well, and where they join the downpipe is subject to issues to avoid blowback into the bath etc :-) thanks to anyone who takes the trouble to respond. regards paul Standard fittings, (branches, bends etc) all have 92.5 or 87.5 degree angles so I assume the fall should be 2.5 degrees. Bob which is 1:22 That is way more than is required. |
#4
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Required drop for toilet outflow
The Natural Philosopher wrote:
Bob Minchin wrote: The Natural Philosopher wrote: grimmy wrote: Hi group... My Dad currently has an en-suite bathroom powered by a macerator. However he wishes to convert this to a normal flush only, but is concerned about the required fall for the waste pipe. Does anybody know what the required angle of elevation is for the waste pipe of a flush toilet? 1:100 minuimum 1:60 ideal from memory. There's other issues as well- best consult an architect or decent builder, or look up the building regs...you need biogger pipes than the macerator as well, and where they join the downpipe is subject to issues to avoid blowback into the bath etc :-) thanks to anyone who takes the trouble to respond. regards paul Standard fittings, (branches, bends etc) all have 92.5 or 87.5 degree angles so I assume the fall should be 2.5 degrees. Bob which is 1:22 That is way more than is required. Maybe this is too steep but how do you avoid using 2.5 degrees when the fitting all come like this? Maybe you know of a source of other fittings Bob |
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Required drop for toilet outflow
"grimmy" wrote in message m... Hi group... My Dad currently has an en-suite bathroom powered by a macerator. However he wishes to convert this to a normal flush only, but is concerned about the required fall for the waste pipe. Does anybody know what the required angle of elevation is for the waste pipe of a flush toilet? thanks to anyone who takes the trouble to respond. regards paul A good rule of thumb Paul, is a 10 mm drop for every 1 mtr of pipe length. Remember also that bends will have to follow this same requirement, so if the bend popping through the wall is part of a 1 mtr measurement, then it needs to follow the rule of 10 mm drop per 1 mtr of length. --- www.basecuritysystems.no-ip.com Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.505 / Virus Database: 302 - Release Date: 30/07/03 |
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Required drop for toilet outflow
From the chaotic regions of the Cryptosphere, Bob Minchin
wrote on Thu, 31 Jul 2003 22:13:02 +0100: The Natural Philosopher wrote: which is 1:22 Maybe this is too steep but how do you avoid using 2.5 degrees when the fitting all come like this? The gradient for _above-ground_ WC branches are between 18mm-90mm per metre, which works out to 1:55 to 1:11, which works out to between 1.03° - 5.14°. So 2.5° is pretty much slap-bang in the middle. Rest of the world 1, Natural Philosopher 0. -- Hugo Nebula "You know, I'd rather see this on TV, Tones it down" - Laurie Anderson |
#8
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Required drop for toilet outflow
Hugo Nebula wrote:
From the chaotic regions of the Cryptosphere, (grimmy) wrote on 31 Jul 2003 12:23:19 -0700: Does anybody know what the required angle of elevation is for the waste pipe of a flush toilet? The above-ground branch needs to have a fall between 18mm and 90mm per metre run. The below ground drain needs to be no shallower than 1:40. Not so. Below ground its advised to be between 1:60 and 1:100 and IIRC not STEEPER than 1:40 |
#9
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Required drop for toilet outflow
Hugo Nebula wrote:
From the chaotic regions of the Cryptosphere, Bob Minchin wrote on Thu, 31 Jul 2003 22:13:02 +0100: The Natural Philosopher wrote: which is 1:22 Maybe this is too steep but how do you avoid using 2.5 degrees when the fitting all come like this? The gradient for _above-ground_ WC branches are between 18mm-90mm per metre, which works out to 1:55 to 1:11, which works out to between 1.03° - 5.14°. So 2.5° is pretty much slap-bang in the middle. Rest of the world 1, Natural Philosopher 0. "A minimum size 100mm branch pipe may be used for a maximum of 8 WC's or a length not exceeding 15m, gradient should be between 9mm and 90mm per meter run" Building regs 2000 edition. From building regs. So min fall is 1:100 roughly. Since this is a macerator replacement, he will want to work as near flat as possible. The steeper gradients you quote are for washbasins and urinals and baths on smaller diameter pipes. External falls depend on anticipated flow rate - i.e. number of bogs connected, and may be in large diamter pipe as low as 1:180. though 1:40- 1:80 is optimum. 1:60 is a good working figure. |
#10
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Required drop for toilet outflow
From the chaotic regions of the Cryptosphere, The Natural Philosopher
wrote on Fri, 01 Aug 2003 09:36:23 +0100: Hugo Nebula wrote: Rest of the world 1, Natural Philosopher 0. "A minimum size 100mm branch pipe may be used for a maximum of 8 WC's or a length not exceeding 15m, gradient should be between 9mm and 90mm per meter run" Building regs 2000 edition. The Building Regulations don't give guidance, the Approved Documents do. (2-0) Perhaps you should download the 2002 edition of AD 'H' (Drainage). (3-0) Table 2 Common branch discharge pipes (unventilated) gives the gradient limits as: Appliance |Max no. to |Gradient limits |be connected|mm fall per metre) __________________________________________________ __ WC outlet 80mm |8 |18(2) to 90 WC outlet 80mm |1 |18 to 90 The footnote (2) to this table reads "May be reduced to 9mm on long drain runs where space is restricted, but only if more than 1 WC is connected". So for the OP's question relating to a single WC, then the minimum fall is 1:55 (4-0) So min fall is 1:100 roughly. Very roughly. (Poor defending nearly let another in) The steeper gradients you quote are for washbasins and urinals and baths on smaller diameter pipes. The lower end of the gradient range is uniform at 18mm/metre(1) across the whole range of appliances. (5-0) External falls depend on anticipated flow rate - i.e. number of bogs connected, and may be in large diamter pipe as low as 1:180. though 1:40- 1:80 is optimum. 1:60 is a good working figure. The OP was about sanitary (above-ground) drainage. It sounds like you're getting this confused with the drains below ground. I don't know of any unpumped drainage serving normal domestic foul drainage that can be installed at 1:180! (6-0) (1) In the UK we use the "metre" spelling for the measure of distance. 7-0 in injury time) -- Hugo Nebula "You know, I'd rather see this on TV, Tones it down" - Laurie Anderson |
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