Simco External Framing Solutions - Manufacturers of Powder Coated Roof and Cladding Trims

Rainwater Goods

Downpipes, square and round, swannecks, shoes, collars or connectors, rodding eyes, brackets and specials make up this section. We offer a wide product range to suit your individual design requirements and site conditions.
Design assistance is on offer if required.

Outlet and Downpipe Capacity

The outlet point in a gutter will usually have a far lower capacity then that of the rainwater pipe it connects into. This is due to water being unable to turn corners and so at the outlet, water tends to form a narrow neck of flow. Once into the Downpipe, this tends to spread out to the inside surface of the pipe and, pulled by gravity, the water accelerates away.

If the outlet has rounded shoulders or tapers from a larger diameter, this can improve capacity considerably. Hoppers and sumps can be introduced to create a head of water that will improve the performance of a system where the designer is restricted in choice. To assist with free flow, it is recommended that outlets are factory welded.

Leaf guards can restrict outlet capacity up to 50%. this takes into account that most leaf guards quickly become blocked with a covering of leaves.

If the percentage of water in Downpipes becomes too great, there is a risk that siphonic action will occur. In the right decision, siphonic action can be very useful, allowing huge volumes of water to be moved by relatively small pipes.

However in areas where siphonic action is not expected, it can cause a number of problems for example, excessive vibration and pipe wear, noise and pipe implosions.

To avoid these risks, these following filling limits in pipes have been set :-

Pipe Diameter (mm)	Maximum Flow (l/s)
50 75 100 150 200	1.7 5.0 10.7 31.6 68.0

Downpipes

To suit the application there is a variety of aluminum down pipe sizes available from 50mm to 200mm in square and round. Aluminum is corrosion resistant, light and can be polyester powder coated to provide an attractive finish. Mild steel is readily available in 100mm diameter but needs to be galvanised after manufacture to provide corrosion resistance. The galvanised coating can be further treated with a polyester powder coating for appearance. This mild steel alternative, while being robust is an expensive option compared to aluminum. Double-sided plastisol coated steel can be lock formed to produce a 100mm square Downpipe to suit the colour of the external cladding of a building. Secret fix and anti climb solutions are also available upon request.

Swannecks and Shoes

Swannecks or offsets and shoes can be produced in any angle and length combination to suit site conditions. Where the offset dimension is not known it is possible to manufacture the horizontal connecting leg over length which can be cut on site and slotted into a standard connector.

Collars/Connectors

There is a range of collars and connectors available, the male and female connector tends to be the most effective in terms of providing a waterproof seal. On aluminum, welded internal connectors are available if smooth clean lines are required.

Brackets

One piece and two piece designs are available to suit site requirements.

Rodding Eyes

Access for Rodding can be fabricated into down pipe with a removable cover plate.