System components


We supplies a patented product that allows a RAINPLUS® siphonic outlet to be transformed into an emergency siphonic outlet by simply adding an Overflow Kit that is adjustable in height and capable of maintaining the same drainage performance.


Entire siphonic system is made up of special patented roof outlets, pipe clamps and other clamping accessories, HDPE pipes and fittings, a software for 3D Design and extremely professional computations.

One of the key elements of the system is the RAINPLUS® outlet that has been designed and manufactured to meet the requirements and testing criteria set by the international standards EN 1253 and ASME A112.6.9. The main components of the outlets are made of stainless steel or molded aluminum alloy, protected by a special resin making them long-lasting.



  • Wide range of drainage flows (Up to 65 ℓ/s with RAINPLUS 110 and up to 14 ℓ/s with RAINPLUS 56
  • Low roof water levels is allowed to trigger the siphonic action.
  • No swirls thanks to the special profile of the anti-votex disk and reduced pressure losses at the inlet.
  • Low Noise levels and maximum operation stability.
  • Easy Installation thanks to the reduced number of components and compact size.
  • Connection with the HDPE system is extremely reliable.
  • Suitable for installation in gutters, even of small dimensions, or not roofs covered with any type of waterproofing material.

Bracketing System

BESSFLOW – RAINPLUS offers a wide range of bracketing systems composed of support rails and relative accessories for installing the entire drainage network, and is available in diameter 50 mm up to diameter 315 mm. The siphonic bracketing system also includes clips with expansion anchors, threaded rods for mounting on support rails



  • Easy pre-fabrication
  • Rapid and simple ceiling mounting of long stretches of collector pipes.
  • Mounting of entire drainage network using a reduced number of bracketing pieces.
  • Alignment of clips and BESSFLOW – RAINPLUS HDPE pipes with the support rail.
  • Capacity of absorbing heat expansion and contraction of the drainage network.
  • Installation without the use of special tools.
  • The clips are anchored to the pipes and support rail using high resistance bolts.

HDPE Pipes and Fittings

BESSFLOW – RAINPLUS HDPE product line has been developed siphonic drainage systems and it is characterized by a wide range of fittings such as access pipes, elbows, reducers and reduced branches.



  • Possibility of pre-fabricating system parts and mounting them on site.
  • Savings in labor costs.
  • Possibility of choosing from the different connection types.
  • No material wastage makes it more economical.
  • Increased safety of the systems.