_THE PREVENTION OF ACCIDENTS_
The safety of workmen depends not altogether upon the stability and
strength of a scaffold, but also upon the use of certain precautions
which, while not requisite for the progress of the work, are most
necessary for the prevention of accidents.
[Illustration: FIG. 138]
Put briefly, the principal of these precautions are:
Ladders should rise at least 6 feet 6 inches above the top platform
they serve.
If the ladder is too short for this height to be allowed, a T piece as
fig. 138 should be fixed across the top of the ladder to give warning
to the workman that he has no higher hand hold.
Ladders above 25 feet in length between foot and rest should be stayed
in the centre to prevent sagging. The stay should be a wooden shaft
with an iron clip. By clipping the rung as shown in fig. 139 they do
not meet the workman’s hands and feet when climbing. The same effect is
gained when the top of the ladder rises considerably above the point of
rest, by staying as shown on fig. 140.
[Illustration: FIG. 139]
[Illustration: FIG. 140]
Ladders should have a level footing and be firmly tied to the point of
rest.
Working platforms should be fitted with guard rails along the outside
and at the ends, at a height of 3 feet 6 inches from the platform.
They may be temporarily removed for the landing of the workmen and
material, although it is not always necessary to do so in the latter
case.
[Illustration: FIG. 141]
If a well is left in the working platform through which to hoist
material, the opening should be guarded with rails as for the outside
and ends.
A well hole, if likely to be of permanent use, should be fitted with a
hinged flap door, that can be shut down as required.
Boards on edge should be fitted on the outside and ends of working
platforms, and should rise above the platform at least 7 inches. This
will allow of a 9-inch board being used standing on the putlogs. They
should not be fixed near ladders where the workmen land. Additional
boards should be placed at the back of any stack of bricks or other
material in order to prevent it falling off the scaffold.
[Illustration: FIG. 142]
Edge boards are usually nailed to the standards. On exposed situations
it is better to tie them, as the wind, continually acting on their
surface, will in time draw the nails.
Platform boards, when lapping, frequently lose their place, being
kicked by the workmen during their progress about the scaffold. When
this happens the boards assume the position shown on fig. 141, and what
is known as a trap is formed. The danger of a trap is shown on fig. 142.
[Illustration: FIG. 143]
Platform boards to be safe from tilting, should not project more than 6
inches beyond the putlogs. At this distance the weight of the workman
is most over the putlog, and even if he stood on the extreme edge,
experiments have shown that his weight is more than counterbalanced by
the weight and length of an ordinary board.
Where scaffold boards are used as a means of communication between
one part of the scaffold and another they should be laid in pairs, so
as to form 'runs’ at least 18 inches wide. To prevent unequal sagging
they should be strapped on the under side. It would be better to have
properly constructed gangways and most decidedly safer.
'Bridging runs’ for barrows are usually three boards wide. Five boards
wide is better, and, as previously shown, they should be joined to
prevent unequal sagging.
Centering should be carried on supports which rise from a solid
foundation (fig. 143). The practice of trusting the supports to keep
their position under pressure from the stay A (fig. 144), or
by being spiked to the new work, is to be regretted, as the only reason
for its use is to effect a very slight saving of timber.
[Illustration: FIG. 144]
[Illustration: FIG. 145]
The various knots, tyings, marryings, &c., should be carefully watched,
as, if used in a damp condition, the cordage relaxes considerably when
drying. The scaffolder should have instructions to examine carefully
all cordage in use and tighten the same as required.
The use of sound plant should be insisted upon. Defective plant should
be at once marked, so that its use cannot be unknowingly continued.
Only the scaffolder or his assistant should be allowed to erect, alter
or adapt the scaffolding for its different purposes. Many accidents,
again, occur owing to the scaffolding having been altered during a
temporary absence of the mechanic, and the reconstruction not having
been made safe by his return. This most frequently happens when the
scaffolding is not under the charge of one responsible person.
No working platform should be used by the mechanic until its
construction is complete. Sufficient plant should be on the job to
enable this to be done without disturbing the platform already in use.
Scaffolds should not be heavily loaded. Apart from the risk of the
timbers failing, the weight, in the case of the bricklayers’ scaffold,
has a bad effect upon the new work.
Fan guards, as shown on fig. 145, are usually erected in urban
districts to safeguard the public from falling material. There is no
reason why, for the safety of the workmen, they should not be always
fixed.
Due care should be exercised by the workmen themselves, and observance
made to the unwritten rules of experience.
The following instance is given as an illustration of what is meant.
[Illustration: FIG. 146]
A scaffolder requiring a pole carried it from point A on
fig. 146 to point B. He carelessly carried it upon his right
shoulder, and in turning the corner the pole hit against the standard
C, the recoil knocking him off the scaffold. If he had carried
the pole on his left shoulder he would have fallen inwardly on the
boards, and his life would not have been lost.