Module 2 Cold Water Systems Flashcards
What are trunk mains ?
They may be as much as 610mm (2ft) in diameter they carry the water in bulk and often over long distances to the built up areas,
What are street mains??
They are pipes off trunk mains, they can be mostly 100mm(4in) which run beneath the street and side streets
How is the plumber involved in connecting to a mains?
It’s usually done by trained main layers but a plumber must arrange for a suitable connection to be made to the main before he can connect a cold water supply to any building
What is the name of the tool used for tapping into a mains?
A ferrule
What will the plumber be responsible for at the ferrule?
For the services connected to the tapping ferrule, can be called to install smaller diameter mains for fire fighting services and extensions to mains within the bounds of a large new building
What way will water mains be laid out in a town in?
Laid out in the form of a grid, the grid provides a ring circuit and each section can be isolated bin the event of a burst mains or backwashed for cleaning as desired without the need to isolate the full town supply
How far below ground should water mains be?
900mm beneath roads and 750mm elsewhere in order to prevent damage owing to settlement or frost
What can water mains be made from??
Pvc , asbestos cement or cast iron
Asbestos cement mains what are they?
These have been used with safety for conveying water which could corrode iron pipes, in can come in various thickness and can withstand the same internal pressures as cast iron
Pvc explains out it?
It is widely used and has sufficient thickness and strength to enable connection to be made
Cast iron mains explain it?
Cast iron mains has proved to be very satisfactory the only problem is their susceptibility to deterioration in certain corrosive soils
What is a mains tapping machine?
A special machine designed to cut into large diameter cast iron distribution mains pipes while the water is still in the pipe and under pressure
What is the name of the pipework from the street water mains to the external local stop valve called??
It’s know as the communication pipe and is connected to the ferrule
What is the name give to the pipe connected to the ferrule that has a bend?
It’s called a goose neck bend and is purposely put into the communications pipe to allow for ground movement
What is the name of the pipe from the stop valve into the house called?
This is know as the service pipe and is usually 750mm underground
What should be done to underground pipe work?
It should be sleeved and both ends should be sealed with mastic to prevent the entry of vermin etc into the house
