UNIFOLD Gutter Lining System - Gutter Systems Utilising Siphonic Drainage

Gutter Systems Utilising Siphonic Drainage - Back To Top

Siphonic outlets fitted to gutter lining systems, which also require to be lined, are integrated into the Unifold Gutter Lining System installation using a Siphonic outlet gutter unit which is a fabricated section of Unifold Gutter Lining System specifically designed to seal Unifold to the siphonic outlet.

Siphonic Drainage systems are very maintenance sensitive. They must be kept clean in order to operate efficiently.

1) Poor Roof And Gutter Maintenance

Quite often siphonic systems are not maintained and as a result the leaf guards and strainers become clogged with debris and in these conditions the siphonic outlets can easily cease to operate.

2) Under-Capacity Or Poorly Maintained Below Ground Drainage

The main flow of water from siphonic drainage needs to be un-interrupted in any way as disturbances to flow rate within below ground pipes will slow the main volume of water and affect roof drainage to the extent where the performance of siphonic outlets could be impaired.

These disturbances could be collapsed or debris filled drains or other pipes entering the drains too close to the siphonic connection.

3) Siphonic Drainage Design

It is quite possible for an early siphonic system to be under-designed, particularly as the changes to our weather systems in recent years has brought different rainfall patterns and increases in rainfall intensity. Such a system could become overwhelmed in the severe storm conditions of today.

Unifold Is Able To Help Solve These Problems - Back To Top

Unifold is able to help solve these problems in the following ways...

1. To introduce "Snorkel" overflows into the system as close as practically possible to each existing siphonic outlet with each snorkel overflow set at an effective design height so that as the siphonic system becomes overwhelmed the overflow system becomes operational and removes the excess water.
   
   
2. Where practical, to increase the "holding" capacity of the gutter, by utilising the construction depth of the roof to extend the height of the Unifold installation, thereby increasing the overall depth of the gutter.
   
   
3. The inclusion of sumps: where conditions allow, can be of great advantage, including improvement of the performance of the siphonic system to helping to minimise maintenance.

The design rainfall event in the UK is 2 minutes (the most intense period of a storm), and so a siphonic system must be designed to function in half of this time.

If the sole of the existing gutter can be insulated to provide a depth of, say 50mm, this depth could be used to introduce Unifold sumps at the outlet positions.

The siphonic outlets at the bottom of the sump fill more quickly and become "fully operational" with only relatively light rainfall.

This also helps if the siphonic outlet is positioned at the side of the gutter or in a side box, a common situation when the sole of the gutter is directly above the eaves beam. The sump will help to concentrate water at the outlet and so improve performance.

These sumps can be fitted with large leaf guards/strainers covering the entire sump area. They provide a much greater surface area than the siphonic outlets and are less liable to blockage, reducing the maintenance sensitivity of the system.