Glossary

Term	Description
Adoptable	Where a water or local authority 'adopts' a drainage/sewer installation. Taking responsibility for future maintenance and repair.
As dug material	Soil which is excavated from a trench where the pipe is to be laid.
Backfill	Material which surrounds the pipe when it is installed.
Bedding	Material upon which pipe is laid.
Combined sewer	A sewer designed to carry foul sewage and surface runoff in the same pipe.
Coupling	A fitting which connects two pipes.
Deformation	Where pipe is compressed by loading.
Equal branch	A fitting designed to connect two drainage runs with the two branches are the same size.
Extrudate	Pipe is manufactured by a process called extrusion
Fitting	An item which is injection moulded and is used for example to connect two pipes together, a junction with another pipe or a bracket to support the pipe
Gully	A type of fitting used to accept stormwater from above ground and feed it into the underground drainage system. Can be trapped or un-trapped.
Injection moulding	The process by which fittings are manufactured.
Inspection chamber	Normally located at the intersection of two or more drainage runs. A moulded chamber base acts as the connecting point for the drainage pipes flowing in and out. Chamber rising pieces are then connected from the base to ground level. A Manhole cover is installed at ground level. The installation provides access for inspection of a section of a drainage installation which is potentially vunerable to blockage.
Perforated pipe	A pipe with holes cut into it. Generally used in soakaways or land drainage. Pipes are available either half or fully slotted.
Slip coupling	A coupling which can be inserted into an existing installation
Solid wall	Pipe with a solid wall thickness.
Structured Wall	Pipe made with a twin-wall structure, a smooth inner bore and external ridged type structure. Twice as strong as standard solid wall pipe.
Unequal branch	A fitting designed to connect two drainage runs with where the two branches are not the same size.