Siphonic Roof Drainage Evaluation

CRM are acknowleged as one of the leading authorities in the UK on siphonic drainage, with wide experience of physical testing of siphonic systems, and have sat as invited expert members of the panel for both the US and British Standards on siphonic roof drainage.

Siphonic roof drainage installations are quite complex in function, but can offer dramatic performance improvements over conventional systems. These systems are still bound by the same overall conditions as conventional systems, in that the level of rainfall to be used for any gutter which may spill water into the building when its capacity is reached should be designed using BSEN12056. CRM carries out pre-tender designs on buildings for a limited cost, commenting on:

  • The suitability of the building for a siphonic system.
  • Suggested gutter sizes if these have not already been decided upon.
  • Designing a suitable rainfall intensity, based on building use and area in the country.
  • Putting together a specification and technical data pack to accompany the legal tender documentation.
Siphonic drainage contracts are mostly let on a system design and install basis, but CRM have been instructed to check the installer's calculations before work commences, and perform a follow up installation checks for some of the UK's leading distribution facility developers. This service offers peice of mind, as spots potentail issue when they can be resolved easliy and cheaplky, before thousands of pounds of dameage may have been caused.

CRM own a full size siphonic gutter test and demonstration rig , which has been used to test systems, and also demonstrate the fundamental principals of siphonic drainage to architects and Engineers.

CRM have sat as members of both the UK and American Society of Mechanical Engineers steering groups on siphonic roof drainage standards, and long term researchers into the workings of siphonic systems, and thus we can offer a level of expertise only possessed by a limited number of people in the country. CRM's lead consulatant in this area, Dr Malcolm Wearing, was responsible for the formation of the Siphonic Roof Drainage Association, and sits as secretary and technical consultant.