THREE-QUARTERS of all clay pipe drainage installations are over-engineered because of poor use of geotechnical survey data, producers have claimed.
Supplier and producer Hepworth Drainage said the greater use of data from pre-project geotechnical surveys could help shave millions of pounds from contracts.
Paul Wydell, Hepworth's Drainage product manager, said the details of these surveys are not taken into consideration when drainage systems are designed, leading to over-engineering of the final drainage layout.
He added: 'In a range of ground conditions there are no product-based requirements for a full granular surround.
'But there has been a historical tendency for specifiers to request full surrounds in the incorrect perception that this is best practice.'