Oxford Method Research Programme

Internal rainwater pipes are laid as follows to the same principle as soil drains. Zones are used for both systems.
Roof outlets within the trough gutters were usually in polypropylene and positioned before the roof covering.
Once the pipework was clear of the building traditional drainage procedures were followed.
By 1988 guidance notes and specifications had been produced for all sections of the 6M Oxford Method system as already shown in this manual on specifications for sanitary appliances.
The following extract from the guidance notes on rainwater gives a clear indication of the procedure to be taken.

 Rainwater Pipework/Gutters

SCOPE
This section deals with external and internal rainwater disposal systems above ground level.

TYPES OF PIPEWORK/GUTTER
There are separate type items for

• Internal rainwater pipework
• External rainwater pipework
• Gutters

In each of the principal materials in current use, namely

• Cast iron
• Galvanised steel
• Aluminium
• UPVC

Asbestos cement has been excluded. It is being replaced by other fibre cement materials.
Rainwater pipes and gutters are also available in copper, zinc, stainless steel and lead.

ALUMINIUM PIPEWORK FOR EXTERNAL USE
Aluminium pipes should not be used for rainwater run-off from copper roofing, valley gutters or pipes.

Shape:
Insert 'round' or 'rectangular'.

Grade and size(s):
BS 2997 specifies two grades, heavy (18 swg) and light (22 swg), and the following range of internal diameters (imperial):
· Light grate: 2, 2.5, 3 in.
· Heavy grade: 2, 2.5, 3, 4 in.

Accessories:
Insert details of, e.g. rainwater heads, shoes, access pipes and leaf guards.

Method of fixing:

Fastenings may be expanding bolts or wood screws of aluminium or stainless steel. Copper based alloys must not be used. Check with manufacturer for fixing centres.

ALUMINIUM GUTTERS
BS 2997 specifies cast, extruded and wrought (pressed or cold rolled) aluminium gutters. The latter have become popular, particularly for replacement work, because they can be formed on site from coiled strip. Transport costs are kept to a minimum and length is limited only by the form of the building and the positions of outlets. Aluminium does not need painting except in aggressive atmospheres or for decorative purposes.

Aluminium gutters should not be used for rainwater run-off from copper roofing, valley gutters or pipes.

Profile
BS 2997 specifies minimum thicknesses:

• Cast: 1/2 in
• Extruded: 1/6 in
• Sheet and strip:
       Light: 20 swg
       Heavy: 14swg

Sizes:
Sizes range from 3 to 6 in. depending on method of manufacture and gauge. Check availability with manufacturers.

Colour:
Polyester powder coated gutters in various colours are available which eliminate the need for on site painting.

Method of jointing:
Insert, e.g. 'Rivetted and sealed with Guttertite'.

Method of fixing:
Insert, e.g. 'Guttersnipe secret brackets at 600 mm centres fixed with aluminium screws'.

Some profiles are available pre-drilled for direct fixing.

UPVC PIPEWORK FOR INTERNAL AND EXTERNAL USE
UPVC pipes to BS 4514 are suitable for use internally, or externally where large pipe sizes are required. Insert 'internal', 'external' or 'internal and external'.

Sizes:
Nominal sizes are 82, 110 and 160 mm.

Colour
Grey, black and white are available. Check with manufacturer.

Accessories:
Insert details of, e.g. rainwater heads, shoes, access pipes and leaf guards.

Manufacturer and reference:
Because of the specified requirement for Kitemark certification, it is not strictly necessary to specify a manufacturer and this sub-item may be deleted. If one or more proprietary systems are to be named, they should be selected from those certified under the BSI Kitemarking Scheme. Check with manufacturers or the BSI Buyer's Guide. If products which are not Kitemarked are specified, delete the reference to Kitemarking.

Rainwater outlet(s):
Insert details of roof and balcony outlets stating manufacturer if different to pipework manufacturer.

Method of jointing:
Insert, e.g.
'Solvent welded'
'Push fit'
'Optional'.

Method(s) of fixing:
Insert, e.g. 'Galvanised steel clips for building into facing brickwork at 1800 mm centres'.

UPVC PIPEWORK FOR EXTERNAL USE
Bs 4576:Part 1 specifies only round pipe. The second type item is therefore intended for pipes of rectangular section or which fail to comply in other respects.

Size(s):
Nominal sizes are 63, 68 and 75 mm. For sizes larger than this, use the preceding type item.

Colour:
Grey, black, white and brown are available. Check with manufacturers.

Accessories:
Insert details of, e.g. rainwater heads, shoes, access pipes and leaf guards.

Manufacturer and reference:
(First type item only)
Because of the specified requirement for Kitemark certification it is not strictly necessary to specify a manufacturer and this sub-item may be deleted. If one or more proprietary systems are to be named, they should be elected from those certified under the BSI Kitemarking Scheme. Check with manufacturers or the BSI Buyers' Guide. If products which are not Kitemarked are specified, delete the reference to Kitemarking.

Method of fixing:
Insert, e.g. 'Black UPVC clips plugged and screwed to brickwork with corrosion resistant screws at 1800 mm centres'.

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