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Glossary

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

A

Adjustable flange

An adjustable flange consists of a ring, in one or several parts assembled together, which bears on an end joint hub and can be freely rotated around the pipe axis before jointing.

Air Valves

Air Valves allow the ingress/escape of air either when filling or draining a pipeline or whilst in operation under working pressure.

Allowable maximum operating pressure

Abbreviation: PMA
Maximum pressure occuring from time to time, including surge, that a component is capable of withstanding in service [EN 545]

Allowable operating pressure

Abbreviation: PFA
Maximum hydrostatic pressure that a component is capable of withstanding continuously in service [EN 545]

Allowable test pressure

Abbreviation: PEA.
Maximum hydrostatic pressure that a newly installed component is capbale of withstanding for a relatively short duration, in order to ensure the integrity and tightness of the pipeline[EN 545]

Anti-clockwise close

(valves) Spindle rotates in an anti-clockwise direction, when viewed from above, to the closed position

B

Backfill

Material used to refill an excavated trench, in particular the material between the embedment material and ground level

BS EN 545

British ratified European Standard for 'Ductile iron pipes, fittings, accessories and their joints for water pipelines - Requirement and test methods'

BS EN 598

British ratified European Standard for 'Ductile iron pipes, fittings, accessories and their joints for sewerage applications - Requirement and test methods'

Butterfly Valves

A butterfly valve is a valve used for flow regulation in which the flow control takes the form of disc. Operation is similar to that of a ball valve, which allows for quick shut off. Butterfly valves are favoured because they are lighter than ball valves.
A plate or disc is positioned in the center of the pipe. Passing through the disc is a rod connected to an gear box or actuator on the outside of the valve. Rotating the rod turns the disc either parallel or perpendicular to the flow.

C

Clockwise close

(valves) Spindle rotates in a clockwise direction, when viewed from above, to the closed position

D

Depth of cover

Vertical distance from the top of the pipe barrel to the surface

DN

Nominal diameter

Ductile iron

An iron/carbon/silicon alloy. When magnesium is added to the molten iron the graphite forms in spheres rather than flakes. This transformation virtually eliminates brittleness and produces a strong ductile material

DWI

Drinking Water Inspectorate - administers the compliance of materials to Regulation 31: all materials that can come into contact with potable water, including pipe linings, lining repair material, joints and jointing lubricants must comply with the requirements of Regulation 31 of The Water Supply Regulations, England and Wales (6), or The Water Supply Regulations for Scotland (7).

E

Embedment

Fill material around the pipe including bedding, sidefill and initial backfill

EPDM

A type of synthetic rubber(ethylene propylene diene monomer) widely used for gaskets in contact with potable water.
EPDM has a low compatibility with oils and aromatic hydrocarbons and is not generally recommended for use with effluents (use nitrile rubber gaskets)

External diameter [OD]

External dimension of the pipe barrel at any cross section.

F

Fabricated Pipe

Saint-Gobain PAM UK offers a range of fabricated pipe tailored to customer requirements. Flange spigot, flange socket and double flanged pipes are available in a variety of lengths in diameter range DN 80-DN 2000 for both water and sewer application.

Flange

Flat circular end of a pipe or fitting extending perpendicular to its axis, with bolt holes equally spaced on a circle.

Note: a flange can be fixed (e.g. integrally cast or welded) or adjustable; an adjustable flange consists of a ring, in one or several parts assembled together, which bears on an end joint hub and can be freely rotated around the pipe axis before jointing.

Flap Valves

The primary application of flap valves is for surface water drainage associated with rivers, estuaries and sea water outfalls to prevent reverse flow conditions. Flap valves can also be utilised on final effluent outfalls for sewage treatment plant to prevent flood damage within the works.

G

Gasket

The rubber sealing component of a joint

I

Initial backfill

Layer of backfill material immediately above the crown of the pipe

Internal diameter [ID]

Internal dimension/diameter of the pipe

Invert

Lowest point of the internal surface of the barrel of a pipe or channel at any cross section

J

Joint

Connection between the adjacent ends of two components including the means of sealing

K

Kameleo

Modular and variably angled, Kameleo offers contractors the real possibility of saving time, effort and money, even on challenging sites.
Normally, a combination of hard bends (45°, 22.5° and 11.25°) are used to connect pipes which do not make a specific angle. Kameleo is different - its continuously variable angle from 0 to 45° means that using two, three or more bends is a thing of the past. Kameleo is a variable angle bend with a variety of connection kits for the ultimate in flexibility and simplified logistics.

L

Length, effective

In practical terms, the effective length of a pipe or fitting is the increase in layed length of a pipeline from installation of the pipe or fitting.
For flanged pipes and fittings, the effective length L, is the same as the overall length.
For socketed pipes and fittings, the effective length Lu, is equal to the overall length minus the maximum spigot insertion depth.

N

Nitrile

Acrylonitrile Butadiene Rubber, usually shortened to Nitrile, was developed in 1941 as the first oil resistant rubber. It is the recommended gasket material for effluent applications because of its resistance to oils and aromatic hydrocarbons.

Nominal diameter [DN]

Nominal internal diameter (DN/ID) or external diameter (DN/OD)

Non-return valve

A non-return valve (also known as a check valve, or one-way valve) is designed to allow liquid to flow through it in only one direction.

P

PEA

see 'Allowable test pressure'

PFA

see 'Allowable operating pressure'

Pipe barrel

Cylindrical part of the pipe excluding socket and spigot

PMA

see 'Allowable maximum operating pressure'

Puddle flange

Where pipes pass through the wall of a building or chamber, a puddle flange may be required to reduce the risk of water passing through the wall. A puddle flange is a plain flange fitted to the barrel of the pipe, which is cast into the structure wall.

R

Resilient Seated Gate Valves

Resilient seated gate valves are designed to isolate one section of pipeline from another. The resilient seated gate valve wedge is fully rubberised with vulcanised rubber.

Repair Clamps

For the temporary repair of localised cracks and breakages in pipelines.

Resistivity, soil

Soil resistivity is a function of soil moisture and the concentrations of ionic soluble salts and is considered to be most comprehensive indicator of a soil’s corrosivity. Typically, the lower the resistivity, the higher will be the corrosivity.
We offer a soil resistivity survey service that is WRc approved and a range of proven external active and barrier coatings to suit all ground conditions.

S

Sewer

Pipeline or other construction, usually underground, designed to carry wastewater from more than one source

Sewerage Air Valve

The valve is suitable for the bulk release or ingress of air whilst filling or draining the line and the release of trapped air whilst the line is under operating pressure. Fouling of the orifice is eliminated by the use of a large float chamber which confines the liquid within the bottom, therefore preventing any leakage of solids into the atmosphere.

Sidefill

Material at the side of the pipe between bedding and initial backfill

Socket

Female end of a pipe or fitting to make the connection with the spigot of the next component

Spheroidal graphite iron

Alternative name for ductile iron. See entry for 'Ductile iron'

Spigot

Male end of a pipe or fitting

Swing Check Valve

see 'Non-return valve'

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