Shallow bath trap OK with single stack?

[Simonxx]

My bath drains very slowly, so I want to replace the standard P trap with a shallow bath trap. However, the waste pipes from the bath drain into a single stack soil pipe and I thouht I'd read somewhere that by law you have to use full-size traps on these. Is this right, or can I go ahead with the shallow trap?
Any help much appreciated
Simon

 

[Bahco]

Shouldn't be a problem if you fit an anti vac trap.

 

[doitall]

Shouldn't be a problem if you fit an anti vac trap.

Didn't think they made such things

 

[Simonxx]

Many thanks for your help, Bacho. will now try to source a suitable anti-vac trap

 

[kevplumb]

failling that try an anti syphon trap and unless the regs have been relaxed you need a 3"" seal

 

[doitall]

failling that try an anti syphon trap and unless the regs have been relaxed you need a 3"" seal

Thats where we came in Kev, I don't think you can buy shallow anti-vac.

And changing the trap won't cure the problem anyway.

Pipe is blocking up or requires an air admittance valve, to which a deepseal anti-vac trap would do

 

[Bahco]

I must admit I was presuming they made shallow anti vac traps for such a purpose, however if there are non on the market then as Doitall says you can fit an air admittance valve. THis allows air in and stops loss of trap seal.
It must be fitted within 150 mm of the appliance.