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Level 2 NVQ Diploma inPlumbing and Domestic

HeatingUnit 010 No 6

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Materials and connections

Objectives

By the end of this session you will be able to:

Describe a range of sanitary materials.

Explain how they are connected.Identify below ground drainage system.

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Types of materials

The main materials used on above ground discharge are made

from plastic and are called PVC u, MuPVC and ABS which can

be either solvent welded or used as push fit fittings.

Polypropylene is push fit only. Some contract will demand that

solvent weld fittings are used.

The way we install installations is subject to a code of practice

BS 8000-13. with the title, Workmanship on building sites.

Code of Practice for above ground drainage and sanitary

appliances. 1989

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Push fit fittings

Type of waste pipe Advantages Disadvantages

Push fit water tight jointing

easy

Pipe is light

Easy to decommission

Allowance for thermal

movement

Immediate testing

after fitting

Pip can sag

Joints can

disengage

External

installation

degraded by UV

light

Advantages and disadvantages of push fit installations

Table 1

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Solvent weld fittings

Type of waste pipe Advantages Disadvantages

Solvent weld Rigid and resist sagging

Neater and more slim

line in appearance

Permanent reliable

jointing

Resistant to most acids.

Alkali or chemicals

Permanent joints

restrict

repositioning

Immediate testing

not permissible

Ventilated area

required because

of fumes while

jointing

UV light will

deterioratepipework

Advantages and disadvantages of solvent weld

Table 2

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Types of materials

Cast iron has been

used for many years

because it is a robust

and reliable material

but it is difficult to

work with. Thispicture shows

pipework connected

with timesaver

connections which

comprise of a rubber

sleeve and two iron

clamps which arebolted together to

make a water tight

seal.

Picture no 1

Access point

located above

flood level ofhighest appliances

Timesaver

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Types of materials

In the past jointing was made by either hot lead or lead wool and caulking.Sometimes this is specified on ancient monuments refurbishments or special job

requirements. You may still have to work on cast iron in refurbishment work but

nowadays it is mainly required for public building and hospitals.

Picture no 2

Horizontal

Cast iron

socket

caulked with

lead

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Waste connections to a soil stack

Boss pipe: this is a manufactured fitting with formed raised

circular profiles which have to be drilled out and an adapter it

then fitted into the newly made hole to receive a waste pipe.

Strap boss: once a hole has been drilled in a soil pipe this

fitting is then glued and strapped on over the hole and thewaste pipe is connected as above.

Waste pipe manifold: this is a manufactured fitting which

often sits on the floor in the corner of a bathroom ant the

purpose made holes accept 32mm and 40mm waste pipes via

the special designed grommet seals. This device also preventscross flow.

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Waste connections to a soil stack

Strap boss ready for installation (A) and one in situ (B)

A

B

Picture no 3

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Waste connections to a soil stack

Boss pipes in situ

B

Picture no 4

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Waste connections to a soil stack

Waste pipe manifold fitted at floor level

B

Picture no 5

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Access to pipework

The Building Regulations: require that there is access to above

ground drainage systems for maintenance, cleaning and

blockages.

This can be achieved by the installation of:

Purpose made access fittings

Access plugs in soil junctions

Access plugs in waste pipe

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Access to pipework

PVCu access at street level next to Cast Iron rainwater shoe. Cast Iron access at high level.

Picture no 6

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Access to pipework

Access points on PVCu and Cast Iron waste pipework

Picture no 7

Access points

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Soil stack connections to a drain

Drain connections are made from a range of materials. Older

properties tend to have either salt glazed earthenware or cast

iron which requires a strong 2:1 ratio to make a robust seal.

PVCu connections and hep sleeve for clay piping are bothmade with Push fit connections and silicone lubricant allows

ease of installation.

A multi-fit adapter can connect almost any combination of soil

pipe materials.

It is important to understand what type of below ground

drainage system exists before making a connection.

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Types of soil stack drain connections

Drain connectionsSalt glazed earthenwareCast iron

PVCu

Hep sleeve

Multi-fit adapter

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Types of soil stack drain connections

Salt glazed earthenware (exposed sections)

Picture no 8

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Types of soil stack drain connections

Multi fit adapter to

connection PVCu above

ground pipework to a spigot

leading to cast iron below

ground pipework. When

fitting a PVCu pipe to a cast

iron socket a different

adapter is required.

Picture no 9

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Quick questions

Which British Standard gives guidance on workmanship when

installing fittings on AGDS?

Name the three main plastic used in waste fittings and

pipework.List the advantages and disadvantages of push fit and solvent

weld fittings.

What are the options available for connection waste pipes to

soils stacks?

How can a connection be made with a cast iron below grounddrainage collar?

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Below ground drainage

The purpose of a below ground drainage system is to take soil

water aka black water and rainwater to a sewer which is

located in the road and then carry this effluent to a sewage

plant where it is processed.

There are three types of below ground drainage systems:

The Separate system

The Combined system

The Partially Separate

(Also Known as Partially Combined system)

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Separate system

With this system foul water and rainwater discharge

individually into separate drainage systems and then into

separate sewers in the street. The foul water is conveyed

directly to the sewage plant where it is processed and the

rainwater flows to the nearest water course.

This system is one most favoured by the local authorities.

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Separate system

Advantages Disadvantages

The sewage plant does not

become overwhelmed when

it rains heavily

Trapped gullies are not

required for the rainwater

pipework

Two drain means that it is

expensive to install

The foul drain does not benefit

from rainwater flushing

Risk of making wrong

connections to the rainwater

Greater number of inspection

chambers required

Advantages and disadvantages of a separate system

Table 3

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Separate system

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Combined system

With this system both foul water and rainwater discharge into

a common sewer making connections to the drains more

simple. This also makes it economic to install.

The Building Regulations no longer recognises that this is a

viable system on any new installations.

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Combined system

Advantages Disadvantages

Drain maintenance is easier

Cheaper to install

Make wrong connections

impossible

Flushing of drain achieved

when it rains

Expensive with regard to

sewage processing as excessive

rainfall in unwieldy to handle

with both types of discharge

passing through the process at

the same time

Advantages and disadvantages of a combined system

Table 4

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Combined system

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Partially separate system

This is a combination of the combined and then separate

system. Two drainage systems are used. One system carries

the foul water and part of the rainwater while the other carries

the rainwater only. Water which is not collected by the surface

water drain is collected in a soakaway.

A soakaway is a pit usually measuring 1m3 which is cut out of

the round 5 m away from the building. The hole is filled with

gravel to allow rainwater to evenly soak away into the water

table.This system is also known as the partially combined system.

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Partially separate system

Advantages Disadvantages

Isolated rainwater

connections to a foul drain

can reduce costs

Rodding eyes can used

instead of expensive

inspection chambers

When installing foul water

outlets care must be taken to

ensure the correct connection

is made

Advantages and disadvantages of a deparate system

Table 3

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Partially separate system

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Soakaway

Soakaway

Illustration no 4

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Connecting appliances to existing

below ground drainage systems

Any connection will depend on the material the below ground

drainage system is made from. Kitchen sinks and basins may

discharge into a back inlet gully providing the waste pipe

protrudes through the grille but above the water level in thegully to ensure that there is an air break and no ingress of foul

air can occur.

A WC can connect directly into a ground floor drain by using a

WC pan connecter. There are many adapters to choose from

ranging from 75-110mm which can allow the fitting of olderand more modern WC pans.

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Connecting appliances to existing

below ground drainage systems

WC can connect

directly into a

ground floor drain

by using a WC pan

connecter. There

are many adaptersto choose from

ranging from 75-

110mm which can

allow the fitting of

older and more

modern WC pans

An angled WC pan connector

WC pan spigot enters here

This spigot fits into the

socket connection on a stack

Picture no 12

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Quick questions

What are the 3 main below ground drainage systems?

Which one is preferred by the local authorities and why?

Which system is cheaper to install but more expensive to

process?What are the dimensions involved in installing a soakaway?

How would you install the waste of a sink into a bag inlet gully?

Stretchers If a foul smell was coming from a soakaway after a

new washing machine had been installed what do you thinkcould have happened?