Appliance Waste Fed Directly Into Soil Pipe Below Floor Level

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I am in the process of building a new utility room and am looking to minimise the drainage requirements for a dishwasher, sink and washing machine. The utility room will be adjacent to an existing outside toilet (to be retained) and I noticed today that the sink next to this toilet drains directly into the soil pipe just below floor level as shown in the photo (sink waste pipe is the grey pipe on the right). Is it acceptable to adopt this setup for my new plumbing i.e. could I have the appliances feed into a trap which then drains directly into the soil pipe below floor level?
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Provided the existing waste pipe is a 40mm diameter, then yes. If it's 32mm then it's unlikely to be able to handle the flow when the appliances pump out.
 
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Apologies, I wasn't clear in my original post, the pipe on the right serves the existing sink and the new waste (if I am allowed to do it this way) would enter from the left. From the responses I have received, it seems that from a building control perspective this method (waste pipes entering the soil pipe below floor level) may be acceptable- am I correct in that assumption?
 
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Thanks everyone for the replies so far - so, presumably then I could just use two 50mm strap on boss connectors below floor level - correct?
 
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Firstly, why do you want to make 2 connections? Secondly, the existing waste goes into a boss pipe, you could open up the unused boss opposite the current sink connection.
 
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The reason for two connections is that I would like to retain the sink on the right hand side of the toilet whereas the utility room will be on the left hand side so to me it seemed to make sense to have two separate connections.
With regards to the existing connection, it's difficult to see exactly how they have done this as it is covered over at this point but I had assumed it went into a boss pipe but I have found quite a few DIY bodges so far in the house (you should have seen the state of the wiring and the brickwork on the porch!) so it wouldn't surprise me if they just cut a hole in the soil pipe. That said, I'm not concerned if the existing setup is incorrect as I will correct this. At this stage, I just wanted to know if I could make the necessary connections in the way I intended (which you have confirmed) so if necessary, I will just change the soil pipe connector for one with two boss entries. Thanks for your help
 
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I was working on the assumption there is one of these FloPlast Solvent Weld 3-Boss Double Socket Short Boss Pipe Grey 110mm | Soil Pipe Fittings | Screwfix.com just under the floor into which the existing waste in connected, but as you say, without further investigation, you wont know. Assuming that is the case, the existing connection should be ok, just leaving you to make a new entry for your appliances.

Boss pipe would probably be the easier option to be fair, trying to get a pair of strap bosses in will require a bit of digging out, and thats assuming you find enough plastic under the floor to connect to!

Best of luck with this, if you need any more help, just come back.
 

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