How do building contractors comply with the Sewers for Adoption guidance when planning below ground drainage?
For companies involved in new build housing, most of the accompanying drainage will be adopted by water companies, but the drainage has to be installed to the correct requirements. That means ensuring compliance across design and regulations, approvals and installation.
The most recent, major change to such requirements came in 2012, stipulating that drainage may be adopted if there are two or more houses connected. This means water companies become responsible for defects in the pipes; consequently, there are specific requirements placed on the manufacture of pipes, fittings and inspection chambers.
Manufacturers such as Polypipe are therefore developing new products and educating both installers and specifiers on what is available to help them meet the standards.
So, adoptable pipes today are produced to a higher stiffness class to ensure they offer the right performance level. This means pipes achieve strength class SN8 as opposed to the previous requirement of SN4. Inspection chambers now need to meet more onerous standards of material and performance as the adopting authorities are keen on the structural integrity of these products.
That means the testing requirements that manufacturers have to comply with are also a lot more stringent. For example, chamber standards are based on an impact test with a 1kg weight dropped from 2.5 metres.
Installers and specifiers need to be more aware of the specifications. For example, Building Regulations Part H pose one set of requirements while Sewers for Adoption 7 poses another. And while there may be some level of awareness in the market, contractors don’t necessarily understand the detail, especially those in the industry that aren’t working with these issues regularly.
Installing covers and gullies in paved areas
Installing inspection chamber covers and gullies in paved areas can be complicated as paving often uses tessellating shapes. So, installing a cover which is shallow or round is going to make it difficult to pave and having additional concrete around it doesn’t look good!
Since March this year, Polypipe has introduced products that allow installers to work with block paving: having square top gullies means there’s no need to shape the bricks (as is necessary with a round top gully) as the square top design has two pieces that can be rotated to align with any block paving.
Polypipe has also created a cover which can be rotated to suit the pattern of the paved area, leaving a professional looking finish. Look out for further changes designed to increase the usability of covers when installing them in block paving.
In addition, Polypipe has designed additional features including two inlets for pipes. This is a more versatile solution, allowing water to run through the gully body via the back inlet into the main drain.
In light of today’s requirements for Sewers for Adoption 7 – and for a more installer-friendly approach – it’s even more necessary for contractors to work with manufacturers that are creating fit for purpose materials along with comprehensive installation guidance.