Any drainage system should have sufficient capacity to carry the expected flows of water at any point in the system. The actual flow in the system depends upon the area to be drained, the rainfall intensity and the position of the outlets.

Gutter Installation

BS EN 12056-3:2000 states that gutters should be normally level (with a gradient of between 1mm/m and 3mm/m where practicable).

This standard also states that "where snow is likely to lie on roofs, the front edge of the gutter should not be higher than the projected line of the roof, unless snow guards or other precautions are used."

Gutter Capacity

The profile and dimensions of a gutter determines the maximum flow rate (capacity), currently given in litres/second. The height of gutter profile determines the maximum length of gutter run before resultant overflow at the 'high point' (i.e. stop-end or mid-way between outlets) calculated per BS EN 12056-3:2000 as 50 x height.

It is most important to consider the position and number of outlets as well as the size of gutter.

Rainfall Intensity

Rainfall and storm intensities vary between differing locations within the UK and a number of pages are devoted in BS EN 12056-3:2000 to variations and safety factors, relating to various types of buildings and gutter locations. Eaves gutters should be designed using a one year storm event, and the intensity found from maps in BS EN 12056-3:2000.

Catchment Area

In accordance with BS EN 12056-3:2000 the drainable catchment area of a pitched roof is calculated by adding half the height to the plan width and multiplying by the length as follows:

Flow rate for Ogee Notched Gutter

Flow rate for Half Round Gutter

Properties

Co-efficient of

Vicat Softening Temperature

Chemical resistance

The material is virtually unaffected by solutions of inorganic acids, alkalis and salts and is resistant to many organic chemicals. It may be softened by some organic materials such as ketones and aromatic compounds. It will not corrode.

Standards

Rainwater systems are manufactured to comply with the requirements of BS EN 607:1996; BS EN 1462-1997; EN 12200-1:2000; BS 4576-1:1989 where applicable.

Installation Guide

Installation instructions for all Polypipe systems are available on request, just call 01709 770 000 and choose Option 2. When fitting our products, the Building Regulations should be followed.

Although rainwater gutter, downpipe and the associated fittings are strong and lightweight, care must be taken when handling. Extra precaution should be taken in cold conditions due to the reduction in impact strength of plastic products.

All gutter and downpipe extrusions should be stored away from direct sunlight and preferably under cover. When stored in any form of racking all extrusions should be supported at no more than two metre intervals.

Fittings should be kept under cover in their respective packaging until such time as required for installation.

Solvent cement should be kept out of direct sunlight or away from any other heat source.

Preparing gutters & pipes

All rainwater gutters and pipes must be squarely cut and allburrs must be removed. It is recommended that a fine toothed handsaw is used. Care must be taken when cutting gutters and pipes in cold or damp conditions due to the slippery nature of the pipe surface.

Ring Soil and Vent System

Push-Fit (Ring Seal) Jointing

1. Where plain end pipe is being used, ensure that the pipe is cut square to its axis and that all burrs are removed.
2. Chamfer the end of the pipe to prevent the ring seal being damaged or displaced when the pipe is inserted into the socket. Fittings with spigot ends are moulded with a chamfer during manufacture.
3. Lubricate the spigot or ring seal with silicone grease or aerosol lubricant.
4. Insert the pipe or fitting into the socket and then withdraw it by approximately 10mm to allow for expansion of the pipework

The following table indicates the approximate number of joints that can be made for each pipe diameter with cleaning fluid and silicone grease.

Support

The following table shows recommended pipe support centres for horizontal and vertical pipework.