Primary Vented Stack System

• previously known as the single stack system

• Installed in most new buildings and domestic premises

• NO separate ventilation pipe required

  • The discharge stack and branch pipes are sized to avoid the need for separate ventilating pipes

• There are limits on length, diameters, gradients and branch waste pipes

  • ​ this system saves space and costs 

  • The distances of sanitary fittings can be exceeded if using resealing (or antisiphon) traps and branch pipe air admittance valves

• Appliances SHOULD be grouped closely together

• BS EN 12056-2 allows external pipework on buildings up to three storeys

• To minimise noise transmission it's recommended 25 mm of insulation around soil pipes passing through a bedroom or living room.

Secondary Ventilated Stack System

• The venting stack is usually half diameter of the discharge stuck

• Appliances SHOULD be grouped closely together

• Separate ventilating overcomes pressure fluctuations that could cause trap seals to be lost

Stub Stack System

• preferred where the numbers of sanitary appliances and their distance to a discharge stack are large

• NO WC connected above 1.3m from the invert of the drain

  • On the stub stuck system the MAX height above the invert to the centre of WC bunch is 1.5m

• MAX 2m from the invert to the highest brunch connection

• Stub Waste connection – direct waste pipe connection to the drainage system

• The top of the Stub Stack SHOULD be finished with End Cup (Screwed Access Plug) or Air Admittance Valve (CAN terminate inside a building)

• Stub stacks may also be used on upper floors where the discharge from the stack is to a ventilated soil stack.

A macerator is a pump that is attached to a toilet that grinds up, or slices, solid waste using a high speed rotational blade which then pumps the waste into the drainage system. Macerators are great for domestic use, but can struggle if anything other than conventional waste is being flushed. If you have commercial premises, then opting for a grinder means your system will handle any kind of waste. That's going to save you having problems with blocked toilets, further down the line. Macerator pumps can be installed behind the toilet pan or in a different location as needed. They can be used with both close-coupled and wall-hung toilets.

Approved Document H offers guidance on drainage including foul and surface water and rainwater, and sanitary waste disposal, including sewage structures and their upkeep.   

The document provides advice on refuse storage of solid waste materials for dwellings, waste disposal, treating waste water, pollution prevention, and the use of appropriate, separate drainage systems. Furthermore, guidance covers the building of hygienic pipework, discharges and cesspools, and the guidelines for building over and around sewers. 

waste water lifters used in domestic dwellings

Waste water lifters are used for pumping waste water and sewage from a low level to a higher level. They are used when it is not possible to remove waste and sewage from a normal gravity system. They are usually factory manufactured units. Key components of waste water lifters include a waste water treatment receiving well called a 'wet well', equipped with lift pumps and piping with valves, a junction box, and an equipment control panel with an alarm system.