Does a washing machine waste pipe need a U-bend?

[Rocksteadyeddie]

In a second floor flat. The outlet from the machine forms a good seal with the waste.. Seems unlikely that any wafty odours are going to come up the pipe. Or am I missing the point?

[netherfield]

Don't know if you need to,but ours is connected just above the U bend for the sink.

[Condi]

Never bothered with one on mine, and its been fine.

[Ferg]

There MUST be a trap between the waste pipe and the soil and vent system. This is either by a spigot on the trap upstream of the trap OR with a standpipe on a trap. Sealing the hose to a wastepipe isn't good for the machine nor is it legal as far as water byelaws are concerned I believe.

[redeye]

you must have a trap/ubend without a trat of water in the bend you will allow the stink and gasses in the soil pipe to enter your home .
not good and its part of building regulations to have them