Long Kitchen waster run (12metres)

[I wonder]

Hi,

I wonder if anyone can tell me the maximum length i can run a 40mm kitchen waste?

This kitchen waste is only for rinsing the odd cup or that based in a pound-shop.

The kitchen sink is 12 metres away from an open drain at the back of the shop and cannot run out the front because it is a main shopping street.

Plus there is only a maximum 8 inch fall between the sink and gully.

Note this is an open gully and this shop has been built for 30 years it is just a new tennent.

SO the question is;

Would i be able to run this kitchen waste 12 metres in length with an overall fall of 7 inches, clipped to a concrete wall and there being no issues with enviromental health, building control?

Please help, thanks

 

[JCplumb]

Waste gradients need to be a 2.5 degree fall. That's about 40mm/metre. So your overall fall needs to be 480mm which is a lot more than 7 inches. That's to comply with regs and good practice.
However I have seen wastes that run for metres along a bathroom floor with no drop at all and apparently with years of good performance behind them.
If you absolutely can't get a better drop than 7 inches over that run you may have problems with it.
Maybe look into a pumped waste system, will be a bit pricey though to rinse the odd cup.

 

[chris watkins]

http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_H_2010.pdf
The above provides some good guidance but the lengths on page 9 (3M max for 40mm & 4M for 50mm) are for branch connections to soil stacks & are design to ensure that the water trap seal is not lost. As you are discharging over a gully which itself is trapped this will not be so much of a problem.
Recommended fall are 18mm min per Metre run. but if installing smooth bore plastic which has been de-burred you can get away with less without to much increase in the rate of blockages.
I would use a waterless trap (HepVO) on the appliance & I don't think you will have to many problems with it so long as it is just waste water & not half a ton of grease / tea leafs.

 

[JCplumb]

18mm/metre ? Woohoo! I can make future boxing ins smaller
I've always gone by the 40mm/metre rule regardless of pipe diameter, you learn something new every day..
I've still got my Treloar book from college, will have a look to see if I once knew this...