Leach field pipes - options?

[BotusBuild]

I think my research has confused me. What type of pipes can I use in a STP leach field? Stiff or flexible pipe (see examples below), or will either do?

 

Slotted 3m single socket stuff like this? - https://www.plastics-express.co.uk/underground-drainage/Underground-Drainage-110mm?product_id=1795

or

Perforated Twinwall Drainage like this? https://www.drainagesuperstore.co.uk/product/perforated-land-drain-coil-pipe-100mm-x-100m.html

 

[Oxbow16]

Hi there

 

I don't have an answer for you, well - at least not a full one.  But it is a very good question and one I have been looking into as well.  

 

What I do know is that the black corrugated stuff in your second link is against building regs.  It even says so on the product page:  "Not suitable as a dispersal drain for septic tanks".  Note also that the second link stuff says it is single wall, not twin.

 

Why this is the case I'm not sure.  I can see that the black corrugated isn't kite marked.  And maybe that's all there is to it?  If there's more to it, then I would love to know why it is not considered suitable.  In terms of durability, I cannot see it being a problem seeing as this is what farmers use as land drainage.  A farmer's field sees a lot more "action" than the average garden!  

 

So if anyone knows of other reasons why it isn't suitable, please enlighten us both :)  

 

Cheers

[Oxbow16]

What I can add is that I spoke to a few suppliers about it and their answers varied as to why black corrugated cannot be used.  For example:

 

-  Because if there is a problem with the tank and more solids were getting through to the drainage field, the pipe would clog more easily.

-  Smooth pipe is better for even distribution across the whole drainage field.  It ensures a smooth flow.

-  You can use black corrugated land drainage pipe.  But you should also follow building reg (!).  

 

 

[Oxbow16]

@BotusBuild  Curios as to what you decided in the end?

[BotusBuild]

@Oxbow16 - the slotted 3m stuff