Polypipe,
the UK’s leading manufacturer of sustainable drainage and water management
solutions, has helped to protect a new £2.7 million medical centre from flash
floods.
The
Loughborough-based company supplied its Polystorm and Permavoid geocellular
water management systems to the 1,191sqm Churchdown Surgery in Churchdown,
Gloucestershire.
Building
on the initial design by the contract engineer Rutter Johnson, Polypipe worked
with consultant engineering firm EPG, and civil engineer and installer NGB
Cheltenham, to review and value-engineer a solution capable of negotiating
various onsite challenges, including an extremely high water table.
Using
the combined design and installation experience of the team, a mixed product
solution was supplied by Polypipe that included a Permavoid system for use
beneath a large permeable paving car park and two Polystorm tanks utilising
anti-floatation measures in soft landscape areas.
Due
to the high water table, a 150mm deep system using 2,614 Permavoid cells
delivered 138m3 of stormwater storage
beneath the hard landscaping surface. Permavoid was also selected due to its
high structural load capacity. Polypipe, EPG and NGB had to tend with a water
table that left only 130mm of cover in large hard landscaped areas, which meant
a shallow attenuation system was required.
In
addition, 200 Polystorm PSM1a crates were used in soft landscaped areas, which
provided a further 40m3 of water
storage. Due to the high water table, both Polystorm attenuation tanks
installed beneath the landscaped areas surrounding the car park were wrapped in
a fully welded impermeable geomembrane. Both systems are designed to cope with
and manage sudden heavy rainfall, which has affected the region in the past
decade.
To
treat oil and capture silt, 35m of Permachannel, Permavoid Biomat and four
Permaceptor separators were used to channel the collected stormwater away from
the site and into local water networks.
Following
consultation with EPG and NGB, Polypipe delivered a customised Permaceptor much
larger than the standard model to manage greater amounts of stormwater
collected from the overall water management system.
Each
modified Permaceptor can treat a larger catchment area over 150sqm and was
installed to reduce the amount of Permachannel and Permavoid Biomat cells
needed within two isolated permeable car park areas separated from the
Permavoid tank.
As
well as this the main Permavoid tank beneath the car park area had a fully
welded membrane to the base and sides.
Phil
Williams, consultant engineer at EPG, said: “This project provided objectives
that we knew Polypipe could deliver upon. With only 130mm cover on the car park
we chose to use Permavoid beneath the car parking bays because of its load
bearing capability, and the ability of the system to negotiate the high water
table on the site.
“By
working with Polypipe’s technical experts, we were able to design a system that
could be considered ‘good practice’ by the SuDS manual, local and national
planning documents.”
Rosie
Cheetham, marketing manager, Polypipe, added: “This is a great example of a
collaborative approach delivering a system that will serve a community for
years to come.
“Our
water management experts worked closely with all parties from the early stages
of the design process to develop and deliver a modern, intelligently engineered
SuDS solution that was easy to install.”
Neil
Bermingham, managing director at NGB (Cheltenham) Ltd, said: “Having been
awarded the full civil engineering and groundworks package, this project
provided a perfect opportunity to continue our collaborative relationship with
Polypipe.
“Using
our installation experience and knowledge of the site, we were able to work
with Polypipe and EPG to provide a value-engineered solution to the client that
offered cost and construction phase benefits in addition to increased
flexibility in future use.
“Having
utilised our own in-house CSWIP-qualified geomembrane welding team, we look
forward to collaborating with Polypipe and EPG on future contracts.”
The
practice, which opened in March 2018 and can serve 20,000 patients, features
consulting rooms, nurse treatment areas, a lift, training rooms and a large car
park.
