soil pipe connection quandary..

[jim]

I have to connect a new vertical soil stack serving a new bathroom to an existing run from another bathroom.

The section of the existing run that offers itself immediately is "horizontal" (i.e. has a slight correct fall but essentially horizontal) and is also above ground and in 110mm plastic pipe with solvent joints.

A short distance from the seemingly nearest connection point the horizontal turns 90 deg and drops vertically for abt 6 ft then underground etc.

I had initially planned to join my new stack into the horizon. run with a 45 deg branch "on it's back" then a short 2-3 ft of new soil pipe "on the angle" and then a 45deg bend to vertical and up to the bathroom - my thinking was and still is to keep the wastes moving in the right direction rather than just landing vertically in the horizontal run.

Looking again there is another feasible (and possible better) option to change the said 90deg bend to a 90deg branch and then plumb into the top of that for the new stack (this would still involve 45 deg bends and a slightly longer run of pipe at 45deg). Doing it this way would also mean hacking out the solvent weld 90deg bend and then presumably fiddling with the remains of the pipes and a pushfit branch....MMMM....

Given the first arrangement will be easiest to do, and that I have the bits to do either, which would be actually be best to do and why? NB the BCO will be "admiring" it so if there are any applicable legalities that I have overlooked/should be aware of - I'd be grateful for advice

cheers Jim

[Phil L]

I can't understand where or how the pipes are situated at the moment....you say there's a 90d bend and then the pipe drops 6ft, then disappears underground? - why?

Starting from the point where the pipe enters the ground, where does it go?

[jim]

Assuming you mean how does the "above ground" pipe run:- backwards from entering ground:- vertically up 6ft, then 90deg bend (house is partially set into hillside) to take "horizontally" along house side wall (towards hillside), past point I want to join to, carries on another 12 ft to another 90deg bend then up vertically 10ft to an existing showeroom &WC.

Part of problem for previous installer was I guess the sunken window light well under most of the horizontal part....

I knew I'd be doing well to describe unambiguously!!

Hope that's clearer? ta Jim

[Phil L]

Yes. Your OP suggested using two 45d bends? - this is not needed - a 90d branch is perfectly acceptable, because the waste is already going through a 90d bend where the existing bathroom joins onto the horizontal, why would your new one be any different? - they are 90d, but they are angled so that the waste goes in one direction, personally I wouldn't have all those 45d bends and pieces on show outside the house

[jim]

because there are the two sections (upstream and downstream) of the "horizontal" pipe run for debris to build up in? (not just one "corner" to go round @ full force)

it would be used on it's back remember...

when placed on it's back and viewed vertically from the branch end, the 90deg branch I have here has almost no shaping *that would be in contact with the soil* (and so influence it's direction) as it drops vertically in partway along the existing horizontal run.

hence my concern with using a 90deg branch as you suggest is with soil "landing" in the horizontal, losing inertia and possibly going the "wrong way" along the horizontal (until gravity stops it) then running out of flushing water and momentum to adequately and reliably clear the horizontal run the "right way" (before dropping down the vertical and recovering momentum etc to main sewer run...)

that's how I arrived at 45deg branch and short 45deg pipe run and 45 deg bend to vertical again idea

So, what would others consider doing in this situation and has anyone had experience/issues/problems with waste blockages, BCOs etc etc in similar situations....

thanks so far jim

[Phil L]

Takle a look at the 90d bends on this page:

190 about a third of the way down is the bend I'm thinking of - it has a gentle slope one way.

Yes, turds may go in any direction once they hit the bottom, but underground drainage is exactly the same - most stacks join into a pipe @ 90D underground which extends 30 yards in either direction, maybe towards next door on each side, they very rarely block up.

[jim]

page:

> D 190 about a third of the way down is the bend I'm thinking of - it has a

that's what I have here i.e.87.5 deg branch

So yes indeed when used vertically on the main axis i.e. "normally" that radiused bend would absolutely ease the turds down with little obstruction

*however* imagine that image of D190 turned 90deg to the right so that it is "on it's back" and the turds are coming *down* into the branch - the radiused bend is now not really any use is it? as the turds would fly past and hit the "back" of the branch before being affected at all by the radiused bit (that would by now be above the turds) - you with me?

maybe - but do they join *vertically* into those horizontal runs to next doors etc? or more likely from horizontal into 90deg horizontal? isn't that why Bregs want to see swept bends at base of stacks? presumably to take verticals into horizontals BEFORE they join into other pipes to/from other stacks/households?

cheers jim

[Phil L]

not really.

I've done quite a bit of work in pubs, hotels and such likes and often the 3 or 4 toilets in cubicles have their stacks all coming down into a horizontal, which then heads downwards via one stack, yours is no different.

[jim]

I expect in those situations one could expect that the "end stall" will always get used regularly and help to keep things clear.. In my situation the "end stall" will be a guest showerroom/wc so may not get used as regualrly as the boys new bathroom I have to connect in.

So if i can live with the aesthetics of the 45deg branch & bend (mostly hidden behind honeysuckle) that would be OK from BCO and/or commmon sense approach then do you think?

cheers jim