3m limit on washing machine waste

[Vladimir]

Hi all,

There is a 3m limit on the length of a waste-pipe from washing machine for an UNVENTILATED branch.

If the waste runs to a gully and not a stack can this length be exceeded i.e is the branch effectively ventilated because it goes to a gully and therefore air can get in at the bottom where the pipe enters the gully grate?

Cheers
V

 

[Bahco]

You are risking trap seal loss with longer runs.
Fit an AAV or an anti vac trap and you will be fine.

 

[ChrisR]

You will find in-line anti syphon valves designed for the purpose, they just shove inside the 3/4" crinkly hose. (ie not a trap)