BS 1212 Part 2 Air gap

[Readingplumber]

Hi
Am unable to find a clear answer to this -

But the water in the cistern with BS 1212 part 2 float valve what is the highest water category that it can be?

Im thinking category 3 has in F and E tank not been able to find anything written in WRAS guidebook.

Can anyone clarify this?
Thanks!

 

[ShaunCorbs]

Cat 5 if you drill the holes to spec

 

[sammathias]

Cat 4 I think. Sorry Shaun

 

[ShaunCorbs]

Cat 4 I think. Sorry Shaun

Ab air gap (standard tank spec / layout) if you drill the holes correctly are fine for cat 5 risks

 

[Readingplumber]

Hi thanks so far but just normal tank with 1212 part 2 valve With out adding extra weir holes into it.

 

[ShaunCorbs]

Hi thanks so far but just normal tank with 1212 part 2 valve With out adding extra weir holes into it.

Correct only thing overflow must be sized correctly and terminate to outside

If into stack / waste pipe needs to have an air gap

Weir holes is an AA air gap

 

[ShaunCorbs]

What you planning on doing that's cat 5 risk ?

 

[Ric2013]

Rainwater, perhaps? I think that can be cat 5 due to bird faeces?

 

[copperman111]

The rainwater harvesting set ups are generally cat 5 due to potential for bacteria etc so yes you would be correct to assume the pigeon faeces would be a cat 5 risk, therefore a suitable back flow prevention set up would be required to provide the appropriate backflow protection against the risk described suirable AB. AA air gaps etc pipe id

 

[chris watkins]

Top one is an AG air gap which is only good for Cat 3.
Bottom is an AF air gap and good for up to Cat 4

 

[chris watkins]

The use of a BS1212 part 2 float valve does in its self guarantee the air gap it just helps with the amount of water that can be stored & still maintain the air gap.
It always down to the Plumber to drill the holes in the right places to achieve this, air gaps are dependant on the size of the inlet & overflow.

 

[chris watkins]

Correct only thing overflow must be sized correctly and terminate to outside

If into stack / waste pipe needs to have an air gap

Weir holes is an AA air gap

View attachment 33924

Sorry Shaun but a weir overflow is an AB.
AA is where inlet is above the cistern overspill & free falls into the cistern. Both however are good for Cat 5 & are the only ones that should be used for a rainwater storage if that is what the OP is doing.
ref - WRAS book 6.13

 

[Ric2013]

The OP hasn't been on this thread since the 4th July, so we do not know what the OP is doing.