Drainage criteria for siphonic roof drainage systems

Siphonic systems were originally developed in Finland and the first major installation in the UK was in 1985/6. The systems are now widely used for large shed-type buildings and also for buildings with unusual structures such as airport terminals and sports stadia. Several proprietary siphonic systems are now available, having different designs of roof outlet and individual computer design packages for sizing the pipework components.
To help identify best practice and provide specifiers with increased confidence about the characteristics and design procedures for siphonic systems, it was decided after consultation with the UK siphonics industry to prepare a draft guidance document that would be proposed for publication as a British Standard.