Please see attached photo. Building is 3 stories high and has an internal cast iron 2.5inch/65mm pipe that runs the entire height. It serves as the grey water outlet for 2 small kitchens. My flat being the ground floor also serves as the exit point into the drain outside. There is a separate cast iron pipe that deals with the rainwater on the exterior. My kitchen is no longer connected to this pipe and instead exits via a standard PVC pipe. My problem is that the disused junction (see photo) is fouling an area where we plan to install a new kitchen. The downpipe in itself isn't a problem but the 'join rings' are getting in the way. The pipe is fixed to the wall but I'm concerned cutting it could result in the entire thing coming down. I would like to either remove the chunky section and replace OR fit some kind of boss that allows me to at least feed into it and lose the separate PVC drain pipe. What's my best solution?
Encounter identical problem some years ago,cut off the collar on branch, leaving a short pipe stub, this was blanked of with a Fernco Flexible End Cap,which is held in place with a jubilee clip. There varous sizes, 2", 3",4" & larger. https://www.plastics-express.co.uk/flexible-couplings/fernco?product_id=2384
Can cut with grinder on red or blue blue, which ever works best & provides enough pipe for end cap to fit & be secured.