On all the old sinks we have, what I am presuming, external ventilation through the wall.

It looks like the waste pipe extends above the bottle trap before exiting horizontally through the wall.

 

My questions,

Is this still required for modern waste? 

What was the purpose, house is 1936, is it just a smell ventilation method?

 

https://ibb.co/27q6k1P

https://ibb.co/487MQP8

Edited July 3, 20215 yr by ash_scotland88

That’s an early example of air admittance, and we’d need to see the whole foul system to say that provision doesn’t need to be retained / observed downstream eg after a modern refurbishment of the bathroom(s). 
If the small bore waste pipes fall vertically for anything more than a metre or so, air admittance ( anti-vacuum ) traps would need to be installed to allow this function to ‘live on’. 

Example of basin trap

It could be borderline for a metre.

I've not seen under the flooring for this sink but going to presume the sink waste falls vertically for about a metre then "90" angle that then enters the drain outside with a lift away cover. The pipe that enters this drain is maybe 30cm max below ground level and can easily be seen.

 

When you say you need to see it what do you need to see/know?

 

I remember from a previous thread of mine some thought my downstairs toilet was siphonic. I'm sure we came to the conclusion it wasn't. If going by the name is any link.

 

Edit:

Done some quick reading.

This is in place of an "open top" waste pipe, correct?

If so I will need to take a wander around the outside tomorrow and have a look.

I know the upstairs toilet has been replaced with a more modern unit and I sometimes feel the smells can linger longer or travel more than in our old (newer) house. But this may also be due to lack of ventilation (eg trickle vent or fan)

Edited July 3, 20215 yr by ash_scotland88