Swing scaffolds should be suspended by wire or
fiber line secured to the outrigger beams, A minimum
safety factor of 6 is required for suspension ropes,
The blocks for fiber ropes should be the standard
6-inch size consisting of at least one double block and
one single block. The sheaves of all blocks should fit
the size of rope used.
The outrigger beams should be spaced no more
than the hanger spacing and should be constructed of
no less than 2-by-10 lumber. The beam should not
extend more than 6 feet beyond the face of the
building. The inboard side should be 9 feet beyond
the edge of the building and should be securely
fastened to the building.
Figure 4-43 shows a swinging scaffold that can be
used for heavy work with block and tackle.
POLE SCAFFOLD CONSTRUCTION
The poles on a job-built pole scaffold should not
exceed 60 feet in height. If higher poles are required,
the scaffolding must be designed by an engineer.
All poles must be setup perfectly plumb.
The lower ends of poles must not bear directly
on a natural earth surface. If the surface is
earth, a board footing 2-inches thick and 6- to
12-inches wide (depending on the softness of
the earth) must be placed under the poles.
If poles must be spliced, splice plates must not
be less than 4-feet long, not less than the width
of the pole wide, and each pair of plates must
have a combined thickness not less than the
thickness of the pole. Adjacent poles must not
be spliced at the same level.
A ledger must be long enough to extend over
two pole spaces, and it must overlap the poles
at the ends by at least 4 inches. Ledgers must
be spliced by overlapping and nailing at
polesnever between poles. If platform
planks are raised as work progresses upward,
the ledgers and logs on which the planks
previously rested must be left in place to brace
and stiffen the poles. For a heavy-duty
scaffold, ledgers must be supported by cleats,
nailed or bolted to the poles, as well as by
being nailed themselves to the poles.
A single log must be set with the longer section
dimension vertical, and logs must be long
Figure 4-43.Swinging scaffold.
enough to overlap the poles by at least 3 inches.
They should be both face nailed to the poles
and toenailed to the ledgers. When the inner
end of the log butts against the wall (as it does
in a single-pole scaffold), it must be supported
by a 2-by-6-inch bearing block, not less than
12 inches long, notched out the width of the log
and securely nailed to the wall. The inner end
of the log should be nailed to both the bearing
block and the wall. If the inner end of a log is
located in a window opening, it must be
supported on a stout plank nailed across the
opening. If the inner end of a log is nailed to a
building stud, it must be supported on a cleat,
the same thickness as the log, and nailed to the
A platform plank must never be less than
2-inches thick. Edges of planks should be
close enough together to prevent tools or
materials from falling through the opening. A
plank must be long enough to extend over three
logs, with an overlap of at least 6 inches, but
not more than 12 inches.
PREFABRICATED SCAFFOLD ERECTION
Several types of scaffolding are available for
simple and rapid erection, one of which is shown in