Adapter
Fitting that provides for connections to
structures, to pipes of other materials,
or to valves.
Adjusting Units
Unit, normally reinforced, used in place
of engineering bricks to adjust the
cover and frame to the required level.
Also known as seating ring.
Backdrop manhole
Manhole with a connection, by means
of a vertical pipe, at or just above
invert, from a drain or sewer at a
higher level.
Backfill Material
Fill placed above the bedding and
surround material above a buried
pipeline.
Barrel
That portion of a pipe throughout
which the internal diameter and crosssection
remain substantially uniform.
Bedding Material
The construction material supporting a
buried pipeline, introduced under or
around the pipes so as to produce, in
combination with the pipes themselves,
a pipeline able to resist the design
loads.
Bedding Class
The design for the bedding of a
pipeline, designed to distribute the
external loads around the whole or
part of the periphery, allowing the use
of a specifi c bedding factor.
Bedding Factor
Ratio of the maximum design load
for the pipe, when installed with a
particular embedment, to the test load
which produces the same maximum
bending moment.
Benching
A surface at the base of the chamber
with the dual purpose of confining
the flow of sewage to avoid the
accumulation of deposits and of
providing a safe working surface.
Bend
Fitting that provides for a change of
alignment within a pipeline.
BSI
British Standards Institution
Butt Pipe
Small lengths of pipe, without a spigot
or socket protruding, built into a
manhole wall to provide a fl exible joint
as close as possible to the outside of
the manhole.
Caisson Method
A method for installing manholes
utilising a steel cutting shoe fitted
to the base section and a specially
developed joint system which enables
shafts to sink into the ground under
their own weight or with limited
downward force.
Chamber
Vertical hollow component of uniform
cross-section except at the joint profile.
Civil Engineering Specification for the
Water Industry (CESWI)
A standard specifi cation for civil
engineering contracts in the UK
water industry.Produced by UK Water
Industry Research Limited.
Concrete Cover
Actual thickness of concrete over any
reinforcement. Cover Slab (or biscuit)
Unit forming the horizontal roof of a
chamber or shaft and having an access
opening, immediately above which an
adjusting unit or frame and cover is
designed to fit. Sometimes known as a
`biscuit’.
Crown
The highest point of the external
surface of pipe barrel at any cross
section.
DN
See `Nominal Size’.
Double Step
A manhole step which is designed to
support two feet or two hands, and
is intended to be installed in a single
vertical alignment.Also known as a
rung.
Drain
Pipeline, usually underground,
designed to carry wastewater and/or
surface water from a source to a sewer.
Effective length
Length between the base of the socket
and the end of the spigot of a unit.
Exfiltration
Escape of sewage from a drain or sewer
system into surrounding ground.
External diameter
Mean external diameter of the pipe
barrel at any cross-section. |
|
Fitting
Adapter, bend, rocker pipe, junction or
butt pipe.
Flexible joint
A type of joint using an elastomeric
joint ring to provide a watertight seal
whilst permitting a specified amount of
movement between adjacent pipes.
Flexible pipe
Pipe, the load carrying capacity
of which is limited by diametral
deformation under load to the ultimate
design criteria without breaking or
overstressing.
Gradient
Ratio between the vertical and the
horizontal projections of a pipe length.
Gravity system
Drain or sewer system where flow is
caused by the force of gravity and
where the pipeline is designed
normally to operate partially full.
Gully cover slab
A frame or surround manufactured
from concrete, with or without a
drainage slot, to accommodate a road
gully grating and frame.
Gully - trapped
A hollow cylinder with base,
manufactured from concrete with an
outlet so designed as to form a water
seal and facilitate the connection of
pipelines, which acts as a rodding eye.
Gully - untrapped
A hollow cylinder with base,
manufactured from concrete with an
outlet to facilitate the connection of
pipelines, which acts as a rodding eye.
Infiltration
Ingress of ground water into a drain or
sewer system.
Inspection chamber
Structure as a manhole, but without
access for personnel.
Integrated seal
Seal incorporated into a unit during
manufacture.
Internal diameter
Mean internal diameter of the pipe
barrel at any cross-section.
In wall joint
A type of joint where the socket is
made within the wall of the pipe,
usually referred to as a rebated, ogee
or tongue and groove joint.
Invert
The lowest point of the internal surface
of a pipe barrel or chamber at any
cross-section.
Jacking pipe
Unreinforced or reinforced concrete
pipe, incorporating a fl exible joint
within the wall thickness, rebated or butt-ended with collar
and designed to be installed by the
pipejacking method.
Joint
Connection between the adjacent
ends of two components including the
means of sealing.
Junction
Fittings used to connect, at an angle,
two separate pipelines.
Kitemark
Third Party Certifi cation symbol which
confirms that the product has been
manufactured to the relevant Standard
and approved by BSI.
Landing slab
Unit forming an intermediate
horizontal platform within a manhole
and having an access opening.
Manhole
Vertical structure used to connect
pipelines, to change direction and/or
level, to permit access for personnel
and/or equipment for inspection and
maintenance and to allow aeration and
ventilation.
Microtunnelling
Method of steerable remote control
pipejacking to install pipes of internal
diameter less than that permissible for
man-entry.
Minimum crushing load
Load that a unit is required to
withstand.
Nominal size
Numerical designation of the size
of a unit or a component within
a structure, which is a convenient
integer approximately equal to
the manufacturing dimension in
millimetres for the internal diameter
(DN).
Ogee Joint
See `Rebated joint’.
|
|
Ogee Pipe
A pipe made with ogee joints.
Open cut
Traditional method of installation with
pipes laid in an open trench prior to
backfilling.
PC
Portland Cement.
Perforated pipe
A pipe with circular perforations.
PFA
Pulverised fuel ash.
Pipejacking
Method for directly installing pipes
be in a shield machine by hydraulic or
other jacking from a drive shaft such
that the pipes form a continuous string
in the ground.
Porous pipe
A hollow cylinder manufactured from
unreinforced porous concrete, of
uniform internal diameter and crosssection
throughout its length, except at
the joint profile.
Rebated joint
A joint made within the wall thickness
of a unit, including ogee and tongue
and groove joints.
Reducing slab
Reducing unit forming the horizontal
roof of a chamber and having a smaller
opening to accommodate a shaft unit
above it.
Reinforced concrete pipe
Pipe that is structurally reinforced
with one or more steel cages, suitable
positioned to resist tensile stresses in
the pipe wall.
Rocker Pipes
Short lengths of pipe jointed to butt
pipes to provide for differential
settlement at manholes.
Rung iron
See `Double step’.
Seating ring
See `Adjusting unit’.
Self-cleansing
Ability of the fl ow in a drain or sewer
to carry away solid particles, which
would otherwise be deposited in the
pipe.
Sewer
Pipeline or other construction, usually
underground, designed to carry
wastewater and/or surface water from
more than one source.
Sewers for Adoption
A design and construction guide for
developers produced by the Water
Service Authorisation for adoptable sewer systems.
Soakaway
Vertical chamber of circular crosssection,
perforated to allow the
passage of water and with or without
an access shaft.
Socket
End part of a pipe which is formed to
accept the insertion of a spigot.
Soffit
The highest point of the internal
surface of a pipe barrel or chamber at
any cross-section.
Specials
Non standard products available on request from manufacturers.
Spigot
End part of a pipe which is formed to
insert into a socket.
Steel banded joints - steel collar
Type of joint where the socket is made
within the wall thickness of the pipe by
means of an integral steel collar. Used
for jacking pipes.
Strength class
Minimum crushing load in kilonewtons
per
metre, divided by one thousandth of its
nominal size (DN).
Stringing out
The process of placing pipes from stack
or lorry alongside the line of the trench
ready for laying.
Surface water
Water from precipitation, which has
not seeped into the ground and which
is discharged to the drain or sewer
system directly from the ground or
from exterior building surfaces.
Tamping
The process of compaction, using
hand or mechanical means, applied to
bedding and backfi ll material around a
buried pipeline.
Unreinforced concrete pipe
Pipe that does not contain structural
steel reinforcement. |
