BS 8490:2007 Guide to siphonic roof drainage systems
BS 8490 is the British Standard applies to roof drainage systems using circular-section pipes that operate under siphonic action. It does not apply to siphonic drainage systems using rectangular or trapezoidal section conduits for water conveyance.
It gives information and provides guidance on design parameters, installation, verification and maintenance needs of siphonic roof drainage systems. Guidance is also given on carrying out checks of designs, for the use of specifiers and regulatory authorities. Particular issues for site drainage systems that receive flows from siphonic roof drainage systems are also covered.
BS 8490 should be read in conjunction with BS EN 12056-3 which deals with the layout and calculation of roof drainage. BS8490 gives information facilitating the use of BS EN 12056-3 in the United Kingdom with regard to siphonic roof drainage systems; it does not alter any of the provisions of that standard.
It is based upon work carried out under a separate study part-funded by the Department of Trade and Industry as part of its Partners in Innovation scheme