Page 80 - 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

KEY TERM ● When erected outdoors, the height of the tower must not be greater than

Sheeting out: sheeting out three times its smallest base measurement.
a tower scaffold means ● Towers higher than 6.4 m must be tied to the building or have adequate
covering the outside of the outriggers fitted.
scaffold with tarpaulins. ● ALWAYS use towers on firm, even ground – NEVER on sloping ground.
This can be extremely ● NEVER place steps on the working platform.
dangerous as the tarpaulins ● NEVER ‘sheet out’ a tower.
act like the sails on a ship
and could easily blow the Mobile tower scaffolds and proprietary mobile scaffolds
scaffold over.
These scaffolds are useful for light work of a short duration, such as installing
boilers and flues. They are usually manufactured from aluminium for lightness.
This scaffold should be used only where the ground is sufficiently firm, level
and smooth to maintain stability. All wheels on mobile types must be the
lockable type and kept locked when the scaffold is in use. The scaffold should
only be moved by exerting force on the bottom of the tower and never pulled
from the top.

Tower scaffolds should never be moved with persons still on them.

ACTIVITY Outriggers
If the base of a scaffold If extra working height is required, then the base measurement can be
measures, say, 2 m × 1.5 m, increased by the use of outriggers. These are tubes or special units that
calculate the maximum connect to the bottom of the tower at the corners, giving a greater overall
height of the tower base measurement. Outriggers also help to stabilise a scaffold tower, as well as
scaffold.
giving extra working height.

IMPROVE YOUR MATHS

Working out the height of a tower scaffold
If the base of the scaffold measures, say,
3 m × 2 m, take the shortest measurement and
multiply by 3. So:

2 m × 3 = 6 m
This means the tower scaffold can be erected
safely to 6 m high.

Mobile tower scaffold requirements
The requirements for mobile tower scaffolds are
the same as for static tower scaffolds, but with
the following additions:
Outriggers
● castors must only be fitted to standards
(vertical uprights)

● castors must be of a swivel type fitted with a
locking device
Lockable wheels
● castors must fitted by a method that prevents

the wheel from falling out if not in contact
with ground.
p Figure 1.46 A correctly erected mobile tower scaffold

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