Page 610 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

The City & Guilds Textbook: Plumbing Book 1

appropriately sized hole saw beforehand, and the correct insert for the waste
pipe size used.
2 By the use of a strap boss: these are solvent welded onto the soil pipe.
Both methods were featured in Chapter 2, Common processes and techniques.
Care should be taken to ensure we install them the right way up, as both boss
pipes and strap bosses have a slight gradient in the moulding to ensure the
correct fall for the waste pipe.

 Figure 9.96 Boss pipe adapter Installing a strap boss, step by step
1 Determine where the strap boss is to be installed and mark the centre of
KEY POINT the hole.
Not all strap bosses have 2 Using the correct size of hole saw and a cordless drill, drill the hole for the
nuts and bolts to keep strap boss, ensuring that the lip on the inside face of the strap boss fits
them in place. Some just snugly inside the hole. It is important not to have too much play in the hole
clip together to make a as this may result in leakage once the solvent cement has set.
watertight seal. All strap
bosses, however, must 3 Clean around the hole and the surface of the strap boss with cleaning fluid.
be solvent welded. 4 Apply solvent cement to the strap boss first and then around the hole on the
soil pipe.
5 Place the strap boss into position, insert the nut and bolt at the back of the
boss, and tighten gently.
6 Clean away any excess solvent cement with a clean, dry cloth.
7 The boss must be left for at least five minutes for the solvent cement to cure
enough for testing to be carried out.

Waste pipes that are to be installed on an internal soil stack can use a waste
pipe manifold. This is an adapter that allows multiple waste pipe connections
and avoids problems with cross-flow exclusion zones.

p Figure 9.97 A waste pipe Access to pipework
manifold Access to AGDS pipework for cleaning, clearing blockages and maintenance is
a requirement of the Building Regulations. There are various ways that we can
fulfil this requirement:

● by the use of access plugs inserted into soil pipe junctions and waste
pipe tees
● by the use of purpose-designed access covers and fittings.

p Figure 9.98 Access plug in soil p Figure 9.99 Purpose-made
junctions access fitting

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