Drainage Areas & Flow Rates for Vertical Spigot Outlets

BS EN 12056-3:2000 (Gravity drainage systems inside buildings – Part 3: Roof drainage, layout and calculation) now specifically limits the drainage capacity that can be used to calculate areas to be drained, so as to prevent siphonic action that may damage internal pipework.
Previous physical testing of all our outlets has shown that the rates and areas (see adjacent table) are lower than results that have been seen from this actual testing.
All rates are assuming that the outlet grate is free and clear of any debris/blockages
Results are based on a rainfall intensity of 75mm per hour and a 35mm head of water adjacent to the outlet (45mm head for 160mm outlets as per EN 1253-2:2015).
The flow rates shown should be used as a guide only. Each drainage area will have individual features that may influence overall flow characteristics.

For further advice, please contact us on (01763) 244446 or email us at info@caro.co.uk.
Vertical Spigot Outlets