If 40mm diameter pipe is used, max length is 3m..
Building regs state between 18 -90mm per metre for a 40mm waste pipe which shouldn't exceed 3m but these figs are no doubt flouted every day. See diagram 3 Building Regs approved Doc H. I just checked the building regs as mentioned above.
The most important bit of obvious advice ever: soil and waste pipes need to be on a downhill gradient! The “fall” or “drop” should be between 1/40 (1cm down for every 40cm across) and 1/110.
By increasing the size of the pipe, you can place the fitting further away – typically between 3 and 4m away for a 50mm pipe.
Running waste pipes through joists should be avoided where possible, as any drilling of joists (also known as notching joists) may weaken them and compromise the structural integrity. When you do need to notch a joist, you should use the following rules: Only insert a notch into the top edge of the joist.
40 mm waste pipes are used in areas where higher volumes of water will be entering the system such as baths, showers and kitchen sinks.
Clips should be fixed at 1.2m centres vertically and 0.5m centres horizontally for 32 and 40mm systems. For 50mm systems, the vertical centres are the same but the horizontal clip spacing can be increased to 0.6m.
The typical rule of thumb according to code requires you to run a horizontal pipe for no more than one-third of the total length.
If a 32mm waste pipe is longer than 1.5 mtrs, a 40mm pipe 3 mtrs, and a 50mm pipe 4 mtrs, then the options are to increase the pipe size to the next size, and/or install an air admittance valve.
It's recommended to avoid having a 90-degree bend as this will lead to blockages and unwanted damage.
The maximum fall for a waste pipe is 1 in 40. The minimum fall is 1 in 110 (apart from vertical pipes, but that's a different story). So pipes with a gradient between 1 in 40 and 1 in 110 should have adequate flow to prevent blockages from occurring.
Polypipe 40mm solvent weld waste pipe actual external diameter is 43mm.
When builders look only at the table without reading the text, they find that a 2-inch-diameter drain can run a maximum distance of 8 feet to the vent.
Six metres is the maximum run according to Building Regualtions, but as you have realised yourself, a good fall on the branch pipe is essential. 2.5º, or 44mm fall for every metre run, is the usual standard. IIRC it is permissible (but inadvisable) to go as low as 18mm per metre, the maximum is 90mm per metre.
Since these pipes shouldn't be carrying contaminated water (stop peeing in the sink when the toilet is occupied!), the waste system doesn't need to be vented the way a soil system does, as no harmful gasses are produced.
If 40mm diameter pipe is used, max length is 3m..
A 32mm waste pipe is typically used for appliances that present low volumes of water to the system (e.g. small hand basins), while 40mm is normally used for kitchen sinks, showers and baths. 50mm, on the other hand, is large to suit commercial applications or connect multiple waste pipes to a single flowing system.
What we can advise is that according to Part H1 Foul Water Drainage, based on a 40mm waste pipe diameter, a 3.0m maximum length from the shower trap to the discharge stack is allowed before venting of the waste pipe is required.
Common Toilet Drain Pipe Sizes
The standard drain line size for a toilet is typically 3 inches in diameter. This size is recommended to ensure proper drainage and to help prevent the inconvenience of clogging. For households with multiple toilets, it is possible to have up to three toilets on a 3-inch common drain.
In general, the maximum distance of the toilet from the main drain should not exceed 4 meters, with a 2% minimum slope. Within these limits, the plumbing system can guarantee an effective draining, avoiding bad smells and the problem of emptying the siphons.
For pipes that have a diameter of 3 inches the distance is 6 feet and for a 4-inch pipe the most it should be away from the vent is 10 feet. Keep in mind that toilets have their own traps so there is no need to have one on the drain line, but it still must have a vent.
The Waste Pipe 3m – 40mm is a common plumbing part used to safely and hygienically carry waste from the house to an external drainage system.
40 mm (1.1/2") BS EN 1451-1 plastic pipe. Do not solvent weld. The actual pipe size is approximately 41 mm o.d. x 36 mm i.d..
How far should the toilet waste pipe be from the wall? This is called your 'toilet rough-in' distance, meaning the distance from the wall to the centre of the waste pipe. Most toilets have a rough-in of 12 inches, although older homes can have 10 or 14 inches.