On 19/04/2020 21:20, Brian Gaff (Sofa 2) wrote:
Do you mean a hopper with the pipe going into it? I still have one on my
upstairs sink. Two possible reasons, Somewhere for noxious fumes to come
out, and a simple way to allow for blockages as you suggest.
My drainpipe has a cranked piece of pipe going up above the gutter to take
the fumes away, but it only takes stuff from the toilet and one would not
want an open hopper on that near a window, but for drains from baths and
sinks its ok usually.
Incidentally, I live in a terrace of four houses, but only the end two have
drains from the gutter, resulting in, when it rains heavily it cascading
down on right angled bends near my inset porch. I put in an extra drain pipe
here into a soak away, however the shrub loved the water so much, a
camellia, its now taken over the soak away and we get a nice little flood by
the front wall.
Brian

in the olden days where connections were made from sinks to cast iron
down pipes in lead and were not very well sealed it was very important
not to have pressure in a foul or waste pipe and have plenty of
venting.....sometimes with a hopper collecting waste and rainwater
.....very true