The naming of pipes

Jon Fairbairn · 2012-07-24T09:10:57+00:00

We have a Victorian flat, and the grey waste exits through someiron pipework under the floor. There are two pipes runningnearly parallel, one above the other (about 5.5m long). Ipresume the upper one serves as a vacuum breaker and as a bufferto reduce the risk of ingress of waste from the flat above.I need to send a message to the plumber¹, and I?d like to be ableto refer to this upper pipe without writing a whole paragraph,so I?m hoping that someone in the group can provide theappropriate term.[1] as in email, rather than horse?s head left on mattress; wewon?t be seeing him before he starts work on the bathroom, so Ineed to send him some details of the work. There?s too much ofit for me to do, but I want to make sure I can maintain itmyself.