MENDIP CARDIFF NEWPORT CAERPHILLY PURBECK SALISBURY PORTLAND EAST DEVON WEST DORSET THE VALE OF GLAMORGAN SEDGEMOOR NORTH WILTSHIRE NORTH DORSET MID DEVON WEST SOMERSET SOUTH SOMERSET RHONDDA, CYNON, TAFF BATH AND NORTH EAST SOMERSET WILTSHIRE EAST DORSET NORTH SOMERSET BRIDGEND POOLE WEYMOUTH AND PORTLAND CITY OF BRISTOL Bath Poole Exeter Swindon Newport Cardiff Bristol Bournemouth Weston-Super-Mare Risca Frome Calne Barry Yeovil Taunton Penarth Nailsea Exmouth Dursley Devizes Dawlish Cwmbran Corsham Bargoed Weymouth Tiverton Sidmouth Ringwood Radstock Minehead Melksham Keynsham Ferndown Clevedon Caldicot Bridport Bridgend Salisbury Pontypool Wellington Warminster Trowbridge Teignmouth Portishead Pontypridd Highbridge Dorchester Chippenham Caerphilly Bridgwater Burnham-on-Sea Chipping Sodbury Chard Watchet Cheddar Wincanton Llanharan Malmesbury Lyme Regis Blandford Forum Pitt Beer Beer Wales Luton Luton Kenny Wookey Stroat Semley Petton Newton Maendy Bagber Weycroft St Athan Batcombe Batcombe Tockington The shading indicates the maximum requirements for radon protective measures in any location within each 1-km grid square to satisfy the guidance in Building Regulations Approved Document C. The requirement for an existing building with a valid postal address can be obtained for a small charge from www.ukradon.org . The requirement for a site without a postal address is available through the British Geological Survey GeoReports service, http://shop.bgs.ac.uk/GeoReports/ . Map 3 Dorset, Somerset, Wiltshire and the Bristol Channel, 100-km grid squares ST and SY (axis numbers are the coordinates of the National Grid) Level of protection required None Basic Full Settlements Bath Weymouth Watchet Semley National Grid 100-km 10-km Other Features LOCAL ADMINISTRATIVE DISTRICT Water features Roads Motorways Primary Roads A Roads B Roads 380 340 360 400 100 320 300 © Crown copyright. All rights reserved [Health Protection Agency][100016969][2007] 80 120 140 160 180 200 Radon potential classification © Health Protection Agency and British Geological Survey copyright [2007]